Bull shark: Difference between revisions

Bull shark
Conservation status
	; Near Threatened (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Order:	Carcharhiniformes
Family:	Carcharhinidae
Genus:	Carcharhinus
Species:	C. leucas
Binomial name
	Carcharhinus leucas; (J. P. Müller and Henle, 1839)
	Range of bull shark

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The bull shark (Carcharhinus leucas), also known as the Zambezi shark or unofficially Zambi in Africa and Nicaragua shark in Nicaragua, is a shark commonly found worldwide in warm, shallow waters along coasts and in rivers. The bull shark is known for its aggressive nature, predilection for warm shallow water, and presence in brackish and freshwater systems including estuaries and rivers.

The bull shark can thrive in both saltwater and freshwater and can travel far up rivers. They have even been known to travel as far up the Mississippi River as Illinois, and in the Ohio River, ^[2] although there have been few recorded freshwater attacks. They are probably responsible for the majority of near-shore shark attacks, including many attacks attributed to other species.^[3]

Bull sharks are not actually true freshwater sharks, despite their ability to survive in freshwater habitats (unlike the river sharks of the genus Glyphis).

Etymology

The name, bull shark, comes from the shark's stocky shape, broad, flat snout, and aggressive, unpredictable behavior.^[4] In India, the bull shark may be confused with the Sundarbans or Ganges shark. In Africa, it is also commonly called the Zambezi River shark or just Zambi. Its wide range and diverse habitats result in many other local names, including Ganges River shark, Fitzroy Creek whaler, van Rooyen’s shark, Lake Nicaragua shark,^[5] river shark, freshwater whaler, estuary whaler, Swan River whaler,^[6] cub shark, and shovelnose shark.^[7]

Anatomy and appearance

A female Carcharhinus leucas at the Shark Reef Marine Reserve, Fiji

Bull sharks are large and stout, with females being larger than males. The bull shark can be up to 81 cm (2.66 ft) in length at birth.^[8] Adult female bull sharks average 2.4 m (7.9 ft) long and typically weigh 130 kg (290 lb), whereas the slightly smaller adult male averages 2.25 m (7.4 ft) and 95 kg (209 lb). While a maximum size of 3.5 m (11 ft) is commonly reported, there is a questionable record of a female specimen of exactly 4 m (13 ft). The maximum recorded weight of a bull shark was 315 kg (694 lb) but may be larger.^[3]^[9]^[10] Bull sharks are wider and heavier than other requiem sharks of comparable length, and are grey on top and white below. The second dorsal fin is smaller than the first. The bull shark's caudal fin is longer and lower than that of the larger sharks, it also has a small snout, and it lacks an interdorsal ridge.^[8]

Bull sharks have a bite force of up to 600 kilograms (1,300 lb), pound for pound the highest among all investigated cartilaginous fishes.^[11]

Distribution and habitat

The bull shark is commonly found worldwide in coastal areas of warm oceans, in rivers and lakes, and occasionally salt and freshwater streams if they are deep enough. It is found to a depth of 150 metres (490 ft), but does not usually swim deeper than 30 metres (98 ft).^[12] In the Atlantic, it is found from Massachusetts to southern Brazil, and from Morocco to Angola. In the Indian Ocean, it is found from South Africa to Kenya, India, and Vietnam to Australia.

Populations of bull sharks are also found in several major rivers, with more than 500 bull sharks thought to be living in the Brisbane River. One was reportedly seen swimming the flooded streets of Brisbane, Queensland, Australia, during the Queensland floods of late 2010/early 2011.^[13] Several were sighted in one of the main streets of Goodna, Queensland, Australia, shortly after the peak of the January 2011, floods.^[14] There are greater numbers still in the canals of the Gold Coast, also in Queensland, Australia. A large bull shark was caught in the canals of Scarborough, two hours north of the Gold Coast.^[15] In the Pacific Ocean, it can be found from Baja California to Ecuador. The shark has traveled 4,000 kilometres (2,500 mi) up the Amazon River to Iquitos in Peru.^[16] It also lives in fresh water Lake Nicaragua, in the Ganges and Brahmaputra rivers of West Bengal and Assam in eastern India and adjoining Bangladesh. It can live in water with a high salt content as in St. Lucia Estuary in South Africa. The bull shark is generally prolific in the warm coastal waters and estuarine systems of the Mozambique Channel and southward, including Kwa-Zulu Natal and Mozambique. The species has a distinct preference for warm currents.

After Hurricane Katrina, many bull sharks were sighted in Lake Pontchartrain.^[17] Bull sharks have occasionally gone up the Mississippi River as far upstream as Alton, Illinois.^[18] They have also been found in the Potomac River in Maryland.^[19]^[20]

Behavior

Freshwater tolerance

The bull shark is the best known of 43 species of elasmobranch in ten genera and four families to have been reported in fresh water.^[21] Other species that enter rivers include the stingrays (Dasyatidae, Potamotrygonidae and others) and sawfish (Pristidae). Some skates (Rajidae), smooth dogfishes (Triakidae), and sandbar sharks (Carcharhinus plumbeus) regularly enter estuaries. Elasmobranchs' ability to enter fresh water is limited because their blood is normally at least as salty (in terms of osmotic strength) as seawater through the accumulation of urea and trimethylamine oxide, but bull sharks living in fresh water show a significantly reduced concentration of urea within their blood.^[22] Despite this, the solute composition (i.e. osmolarity) of a bull shark in freshwater is still much higher than that of the external environment. This results in a large influx of water across the gills due to osmosis and loss of sodium and chloride from the shark's body. However, bull sharks in freshwater possess several organs with which to maintain appropriate salt and water balance; these are the rectal gland, kidneys, liver and gills. All elasmobranchs have a rectal gland which functions in the excretion of excess salts accumulated as a consequence of living in seawater. Bull sharks in freshwater environments decrease the salt-excretory activity of the rectal gland, thereby conserving sodium and chloride.^[23] The kidneys produce large amounts of dilute urine, but also play an important role in the active reabsorption of solutes into the blood.^[23] The gills of bull sharks are likely to be involved in the uptake of sodium and chloride from the surrounding freshwater,^[24] whereas urea is produced in the liver as required with changes in environmental salinity.^[25]

Initially, scientists thought the sharks in Lake Nicaragua belonged to an endemic species, the Lake Nicaragua shark (Carcharhinus nicaraguensis). In 1961, following specimens comparisons, taxonomists synonymized them.^[26] They can jump along the rapids of the San Juan River (which connects Lake Nicaragua and the Caribbean Sea), almost like salmon.^[12] Bull sharks tagged inside the lake have later been caught in the open ocean (and vice versa), with some taking as little as seven to eleven days to complete the journey.^[26]

Bull sharks are able to regulate themselves to live in either fresh water or salt water. It is possible for the bull shark to live in fresh water for its entire life, but it has been observed that this does not happen for certain reasons, mostly due to reproduction. Young bull sharks will leave the brackish water in which they are born and move out into the sea in order to breed with bull sharks of the other sex. While theoretically, it may be possible for bull sharks to live in purely freshwater, it was observed that the bull sharks that were being experimented on had died within four years. The stomach was opened and all that was found were 2 small fishes that were unidentifiable. The cause of death could have been starvation since the primary food source for bull sharks resides in salt water. ^[27]

The bull shark is known to be able to live in both saltwater and freshwater. It is one of the special abilities that the bull shark possesses that dictates how the bull shark is able to breed in safety. it was found in a research experiment that the majority of the time, the bull sharks were found to be at the mouth of an estuary.^[28] The water salinity was tested every month to test for if the difference in salinity is what drove bull sharks into the river or not. It was found that the bull shark stayed at the mouth of the river independent of the salinity of the water. ^[28] The driving factor for a bull shark to be in freshwater or saltwater depends on its age because as the bull shark ages, the tolerance for very low or high salinity increases.^[28] It was found that the majority of the newborn or very young bull sharks were found in the freshwater area, whereas the much older bull sharks were found to be in the saltwater as they had developed a much better tolerance for the salinity.^[28] This is one of the reasons why adult bull sharks will travel into the river in order to have the offspring. The newborns are not born with a high tolerance for high salinity, so they are born in freshwater and stay there until they are able to travel out.

Diet

Bull sharks are typically solitary hunters,^[12] but occasionally hunt in pairs.^[29] They often cruise through shallow waters, and can accelerate rapidly and be highly aggressive, even possibly attacking a racehorse in the Brisbane River in the Australian state of Queensland.^[30] They are extremely territorial and attack animals that enter their territory.

The bull shark's diet consists mainly of bony fish and sharks, including other bull sharks,^[3] but can also include turtles, birds, dolphins, terrestrial mammals, crustaceans, echinoderms, and stingrays. They hunt in murky waters because it is harder for the prey to see the shark coming.^[1]^[31] Bull sharks have been known to use the bump-and-bite technique to attack their prey.

The bull shark is known to be a solitary hunter, although there are brief moments in which the bull sharks will team up with another bull shark in order to make it easier to hunt and to trick prey.^[32]

Sharks are known to be opportunistic when feeding, ^[33] and the bull shark is no exception to this, as it is part of the Carcharhinus family of sharks. Normally, sharks eat in short bursts, and when food is scarce, sharks digest for a much longer period of time in order to avoid starvation.^[33] The bull shark continues to bite and tackle its prey until the prey is unable to escape, and then the bull shark eats its prey.^[33]

The bull shark is known to populate the Indian River. In Florida, researchers examined the contents of the bull shark's stomach. Stingrays and Ariid catfishes, which are both abundant in the Indian River, were found to be in the stomach of examined bull sharks.^[34] One surprising discovery, the head of a small shark, was found, suggesting that the bull shark is capable of feeding upon other sharks in addition to the other fish that it preys on. ^[34]

It also has been cited in the San Juan River area, that the bull shark had consumed sharks. Vorenburg induced a "shark eat shark" environment in which lemon sharks and bull sharks were put into an environment where they had to fight for food, and the injured sharks from the bouts were consumed by the bull sharks. In addition to lemon sharks, they also fed on young sandbar sharks. There has been no evidence to prove that there are different feeding patterns among young and adults or among males and females. Bull sharks do not actively seek out food, but rather are dependent on anything that is available to them. As part of their survival mechanism, bull sharks will regurgitate the food in their stomachs in order to escape from a predator as they stop for the regurgitated food.^[35]

Reproduction

Bull sharks mate during late summer and early autumn,^[36] often in the brackish water of river mouths. After gestating for 12 months, a bull shark may give birth to four to ten live young.^[36] They are viviparous; they are born live and free-swimming. The young are about 70 cm (27.6 in) at birth and take 10 years to reach maturity. Coastal lagoons, river mouths, and other low-salinity estuaries are common nursery habitats.^[3]

175 cm to 235 cm seems to be the size of a fully matured female bull shark that produce viable eggs for fertilization. The courting routine between bull sharks has not been observed in detail as of yet. It is speculated that the male bites the females on the tail until they turn upside down and they male can copulate at that point. At some points, the harassment of the male can become violent. It is not uncommon to see scratches and other marks on a mature female from the mating ritual.^[37]

Bull sharks have an unusual migratory pattern in comparison to other sharks. They are found in rivers all over the world. They have the ability to go from seawater and freshwater. They give birth in the freshwater of rivers. The young bull sharks are free from predators while they grow up in the river before they go out to the sea in order to find mates.^[38]

The ability to be able to survive in both freshwater and saltwater also gives another benefit that has been driven by evolution. Because the majority of sharks are only able to survive in saltwater, the bull shark has evolved to have their offspring in the freshwater where other sharks cannot enter.^[39] The freshwater acts as a protective area where the young are able to grow and mature without the threat of larger sharks preying on the younger bull sharks.^[39] This is an explanation for the behavior that is observed from the bull sharks as to why there would be any reason for the adult bull shark to ever travel into a freshwater area despite being able to tolerate the high salinity of marine water.

Bull sharks are born alive in freshwater which is in contrast to most sharks since they lay eggs. The average litter for a female bull shark is around 1 to 13 pups.^[40] The average time span for a female bull shark to be pregnant is around 10 to 11 months.^[41] The male bull shark is able to begin reproducing around the age of 15 years while the female cannot begin reproducing until the age of 18 years.^[41] Unlike most sharks though, the bull shark does not rear their young like other sharks, the young bull sharks are born into flat, protected areas.^[41] Freshwater presents a natural defense against most larger predators, and the flat land is an added defense as most large predators will not swim in shallow areas. This increases their chance of survival since the parents do not rear the young in the traditional manner. This is also the reason why there is a high mortality rate in young bull sharks. Since the parents do not rear and protect the young, any predator that is able to attack a young bull shark is easily able to kill and eat the young bull shark without much resistance.^[42]

Interactions with humans

Photo of bull shark in shallow water — Bull shark (Bahamas)

Since bull sharks often dwell in very shallow waters, they may be more dangerous to humans than any other species of shark,^[12] and along with the tiger shark, oceanic whitetip and great white shark, are among the four shark species most likely to attack humans.^[4]

One or several bull sharks may have been responsible for the Jersey Shore shark attacks of 1916, which were the inspiration for Peter Benchley's novel Jaws.^[43] The speculation of bull sharks possibly being responsible is based on some attacks occurring in brackish and freshwater.

The bull shark is responsible for attacks around the Sydney Harbour inlets.^[44] Most of these attacks were previously attributed to great white sharks. In India, bull sharks swim up the Ganges River and have attacked people. Many of these attacks have been attributed to the Ganges shark, Glyphis gangeticus, a critically endangered river shark species that is probably the only other shark in India able to survive in fresh water, although the sand tiger shark was also blamed during the 1960s and 1970s.

The bull shark prefers coastal water which is less than 100 feet in depth. This is mostly due to their feeding patterns since they prefer murky waters. This is also a problem since this gives the most interaction with humans. It is known that bull sharks inhabit areas off the coast of Florida, and there have been reports of bull sharks getting close enough to the coast to attack humans since the bull shark is a territorial animal.^[45]

Visual cues

Behavioral studies have confirmed that sharks can take visual cues in order to discriminate between different objects.^[46] The bull shark is able to discriminate between colors of mesh netting that is present underwater. ^[46] It was found that bull sharks tended to avoid mesh netting of bright colors rather than colors that blended in with the water. Bright yellow mesh netting was found to be easily avoided when it was placed in the path of the bull shark. This was found to be the reason that sharks are attracted to bright yellow survival gear rather than ones that were painted black. ^[46] This is very important because it gives an insight into how bull sharks are able to pick up certain visual keys underwater that might give them an advantage when seeking out certain prey.

Energy conservation

In 2008, researchers tagged and recorded the movements of young bull sharks in the Caloosahatchee River estuary. Specifically, they were testing to find out what determined the movement of the young bull sharks.^[47] It was found that the young bull sharks synchronously moved downriver when the environmental conditions changed.^[47] This large movement of young bull sharks were found to be moving as a response rather than other external factors such as predators. An interesting find was that the movement was directly related to the bull shark conserving energy for itself. One way the bull shark is able to conserve energy is that when the tidal flow changes, the bull shark uses the tidal flow in order to conserve energy as it moves downriver.^[47] Another way for the bull shark to conserve energy is to decrease the amount of energy needed to osmoregulate the surrounding environment.^[47]

Ecology

Bull sharks are apex predators and rarely have to fear being attacked by other animals. Humans are their biggest threat. Larger sharks, such as the tiger shark and great white shark, may attack them.^[3] There have been stories documented in the media of saltwater crocodiles preying on young bull sharks in the rivers and estuaries of Northern Australia.^[48]

Notes and references

^ ^a ^b Template:IUCN2011.1
^ Sharks In Illinois. In-Fisherman (16 July 2012). Retrieved on 30 November 2013.
^ ^a ^b ^c ^d ^e "Bull shark". Florida Museum of Natural History. Retrieved 8 September 2006.
^ ^a ^b "Bull shark". National Geographic. Retrieved 3 April 2011.
^ "Biology of Sharks and Rays". ReefQuest Centre for Shark Research. Retrieved 19 August 2010.
^ McGrouther, Mark (12 May 2010). "Bull Shark, Carcharhinus leucas Valenciennes, 1839 – Australian Museum". Australian Museum. Retrieved 19 August 2010.
^ Allen, Thomas B. (1999). The Shark Almanac. New York: The Lyons Press. ISBN 1-55821-582-4.
^ ^a ^b "Shark Species; Bull Sharks". Shark Diver Magazine. 17: 34. 2003.
^ "The Rosenstiel School of Marine & Atmospheric Science".}
^ "9 Biggest Sharks Ever Caught". Total Pro Sports.com.}
^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/j.zool.2012.04.007, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/j.zool.2012.04.007 instead.; for a popular summary, see Walker, Matt (12 October 2012). "Bull sharks have strongest bite of all shark species". BBC News. Retrieved 12 October 2012.
^ ^a ^b ^c ^d Crist, Rick. "Carcharhinus leucas". University of Michigan Museum of Zoology, Animal Diversity Web. Retrieved 8 September 2006.
^ "Queensland rebuilding 'huge task'". BBC News. 12 January 2011.
^ Bull sharks seen in flooded streets | Offbeat | Weird News, Odd and Freaky Stories in Northern Rivers | Clarence Valley Daily Examiner. Dailyexaminer.com.au (14 January 2011). Retrieved on 4 May 2012.
^ Berrett, Nick (14 November 2008). "Canal shark shock". Redcliffe & Bayside Herald. Quest Community Newspapers. Retrieved 26 March 2009.
^ Shark Gallery. Bull shark (Carcharhinus leucas). sharks-med.netfirms.com
^ High number of sharks reported in Lake Pontchartrain. wwltv.com. 16 September 2006
^ "Sharks in Illinois". In-Fisherman. Retrieved 26 July 2010.
^ 8-Foot Shark Caught In Potomac River. Nbcwashington.com. Retrieved on 4 May 2012.
^ Zauzmer, Julie (22 August 2013). "Man catches 2 bull sharks in Potomac". Washington Post.
^ Compagno, Leonard I.V. and Cook, Sid F. (1995). "Freshwater elasmobranchs; a questionable future". Florida Museum of Natural History Ichthyology Department. Retrieved 27 April 2011. {{cite web}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
^ Pillans, R.D. (2004). "Plasma osmolyte concentrations and rectal gland mass of bull sharks Carcharhinus leucas, captured along a salinity gradient". Comparative Biochemistry and Physiology A: Molecular and Integrative Physiology. 138 (3): 363–371. doi:10.1016/j.cbpb.2004.05.006. PMID 15313492. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ ^a ^b Pillans, R.D. (2005). "Freshwater to seawater acclimation of juvenile bull sharks (Carcharhinus leucas): plasma osmolytes and Na⁺/K⁺-ATPase activity in gill, rectal gland, kidney and intestine" (PDF). Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology. 175 (1): 37–44. doi:10.1007/s00360-004-0460-2. PMID 15565307. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Reilly, B.D. (2011). "Branchial osmoregulation in the euryhaline bull shark, Carcharhinus leucas: a molecular analysis of ion transporters". The Journal of Experimental Biology. 214 (17): 2883–2895. doi:10.1242/jeb.058156. PMID 21832131. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Anderson, W.G. (2005). "Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas". Journal of Experimental Zoology Part A: Comparative Experimental Biology. 303A (10): 917–921. doi:10.1002/jez.a.199. PMID 16161010. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ ^a ^b Fresh Waters: Unexpected Haunts. elasmo-research.org. Accessed 6 April 2008.
^ Montoya, Rafael Vasquez (1982). "The bull shark and largetooth sawfish in Lake Bayano, a tropical man-made impoundment in Panama". Env. Biol. Fish. 7 (4): 341–347. doi:10.1007/BF00005568. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ ^a ^b ^c ^d Heupel, Michelle R. (2008). "Movement and distribution of young bull sharks Carcharhinus leucas in a variable estuarine environment" (PDF). Aqutic Biology. 1: 277–289. doi:10.3354/ab00030. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Life of Bull Shark | Life of Sea. Life-sea.blogspot.com (15 November 2011). Retrieved on 30 November 2013.
^ "Shark mauls horse in Brisbane River". Sydney Morning Herald. 23 March 2005.
^ Kindersley, Dorling (2001) in Animal, David Burnie and Don E. Wilson (eds.) London & New York: Smithsonian Institution, ISBN 0789477645.
^ Bull Sharks, Carcharhinus leucas. Marinebio.org (14 January 2013). Retrieved on 30 November 2013.
^ ^a ^b ^c Motta, Philip J (2001). "Advances in the study of feeding behaviors, mechanisms, and mechanics or sharks". Environmental Biology of Fishes. 60 (60): 131–156. doi:10.1023/A:1007649900712. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ ^a ^b Snelson, Franklin F (1). "Food Habits, Occurrence, and Population Structure of the Bull Shark, Carcharhinus Leucas, in Florida Coastal Lagoons". Bulletin of Marine Science. 1: 71–80. {{cite journal}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Tuma, Robert E (1976). Investigations of the ichthyofauna of Nicaraguan lakes. American Society of Ichthyologists and Herpetologists.
^ ^a ^b McAuley, R. B. (2007). "Distribution and reproductive biology of the sandbar shark, Carcharhinus plumbeus (Nardo), in Western Australian waters". Mar. Freshwater Res. 58 (1): 116–126. doi:10.1071/MF05234. The proportion of mature males with running spermatozoa increased from 7.1% in October to 79 and 80% in January and March, respectively, suggesting that mating activity peaks during late summer and early autumn. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Jenson, Norman H (1976). "Investigation of the Icthyofauna of Nicaraguan Lakes". American Society of Ichthyologists and Herpetologists. {{cite journal}}: Cite journal requires |journal= (help)
^ Bres, M (1993). "The Behaviour of Sharks" (PDF). Reviews in Fish Biology and Fisheries. 3 (2): 133–159. doi:10.1007/BF00045229.
^ ^a ^b Heupel, Michelle R. (14 May). "Shark nursery areas: concepts, definitoin characterization and assumptions". Marine: Ecology Progress Series. 337: 289–297. doi:10.3354/meps337287. {{cite journal}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ Pacific Shark Research Center » Featured Elasmobranch – Bull Shark. Psrc.mlml.calstate.edu (16 February 2009). Retrieved on 30 November 2013.
^ ^a ^b ^c Fact Sheet: Bull Sharks. Sharkinfo.ch (15 October 1999). Retrieved on 30 November 2013.
^ Bull Shark – Animal Facts and Information. Bioexpedition.com. Retrieved on 30 November 2013.
^ Handwerk, Brian. "Great Whites May Be Taking the Rap for Bull Shark Attacks". National Geographic News. Retrieved 1 February 2007.
^ Quinn, Ben (15 March 2009). "Shark attacks bring panic to Sydney's shore". The Guardian. London. Retrieved November 2009. {{cite news}}: Check date values in: |accessdate= (help)
^ Frantz, Vickie (18 July 2011). "Bull Sharks Attacks Comonly in Warm, Shallow Waters". accuweather.
^ ^a ^b ^c Bres, M. (1993). "The behaviour of sharks". Reviews in Fish Bviology and Fisheries. 3 (2): 133–159. doi:10.1007/BF00045229.
^ ^a ^b ^c ^d Ortega, Lori A. (2009). "Movement patterns and water quality preferences of juvenile bull sharks (Carcharhinus lecuas) in a Florida estuary". Evionrmen Biol Fish. 84 (4): 361–373. doi:10.1007/s10641-009-9442-2. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
^ "No Bull: Saltwater Crocodile Eats Shark". UnderwaterTimes.com. 13 August 2007. Retrieved 15 June 2008.

General references

"Carcharhinus leucas". Integrated Taxonomic Information System. Retrieved 23 January 2006.
Froese, Rainer; Pauly, Daniel (eds.) (2005). "Carcharhinus leucas" in FishBase. 09 2005 version.
Bull shark, Carcharhinus leucas at marinebio.org
Sunday Herald Sun, Sunday, 23 April 2005

External links

Bull shark at Curlie

[IUCN-1] Template:IUCN2011.1

[2] Sharks In Illinois. In-Fisherman (16 July 2012). Retrieved on 30 November 2013.

[FLMNH-3] "Bull shark". Florida Museum of Natural History. Retrieved 8 September 2006.

[NatGeo-4] "Bull shark". National Geographic. Retrieved 3 April 2011.

[elasmo-5] "Biology of Sharks and Rays". ReefQuest Centre for Shark Research. Retrieved 19 August 2010.

[6] McGrouther, Mark (12 May 2010). "Bull Shark, Carcharhinus leucas Valenciennes, 1839 – Australian Museum". Australian Museum. Retrieved 19 August 2010.

[Allen-7] Allen, Thomas B. (1999). The Shark Almanac. New York: The Lyons Press. ISBN 1-55821-582-4.

[Bull_Shark_SDM-8] "Shark Species; Bull Sharks". Shark Diver Magazine. 17: 34. 2003.

[9] "The Rosenstiel School of Marine & Atmospheric Science".}

[10] "9 Biggest Sharks Ever Caught". Total Pro Sports.com.}

[11] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1016/j.zool.2012.04.007, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1016/j.zool.2012.04.007 instead.; for a popular summary, see Walker, Matt (12 October 2012). "Bull sharks have strongest bite of all shark species". BBC News. Retrieved 12 October 2012.

[ADW-12] Crist, Rick. "Carcharhinus leucas". University of Michigan Museum of Zoology, Animal Diversity Web. Retrieved 8 September 2006.

[13] "Queensland rebuilding 'huge task'". BBC News. 12 January 2011.

[14] Bull sharks seen in flooded streets | Offbeat | Weird News, Odd and Freaky Stories in Northern Rivers | Clarence Valley Daily Examiner. Dailyexaminer.com.au (14 January 2011). Retrieved on 4 May 2012.

[15] Berrett, Nick (14 November 2008). "Canal shark shock". Redcliffe & Bayside Herald. Quest Community Newspapers. Retrieved 26 March 2009.

[16] Shark Gallery. Bull shark (Carcharhinus leucas). sharks-med.netfirms.com

[17] High number of sharks reported in Lake Pontchartrain. wwltv.com. 16 September 2006

[18] "Sharks in Illinois". In-Fisherman. Retrieved 26 July 2010.

[19] 8-Foot Shark Caught In Potomac River. Nbcwashington.com. Retrieved on 4 May 2012.

[20] Zauzmer, Julie (22 August 2013). "Man catches 2 bull sharks in Potomac". Washington Post.

[21] Compagno, Leonard I.V. and Cook, Sid F. (1995). "Freshwater elasmobranchs; a questionable future". Florida Museum of Natural History Ichthyology Department. Retrieved 27 April 2011. {{cite web}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

[22] Pillans, R.D. (2004). "Plasma osmolyte concentrations and rectal gland mass of bull sharks Carcharhinus leucas, captured along a salinity gradient". Comparative Biochemistry and Physiology A: Molecular and Integrative Physiology. 138 (3): 363–371. doi:10.1016/j.cbpb.2004.05.006. PMID 15313492. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[bo-23] Pillans, R.D. (2005). "Freshwater to seawater acclimation of juvenile bull sharks (Carcharhinus leucas): plasma osmolytes and Na⁺/K⁺-ATPase activity in gill, rectal gland, kidney and intestine" (PDF). Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology. 175 (1): 37–44. doi:10.1007/s00360-004-0460-2. PMID 15565307. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[24] Reilly, B.D. (2011). "Branchial osmoregulation in the euryhaline bull shark, Carcharhinus leucas: a molecular analysis of ion transporters". The Journal of Experimental Biology. 214 (17): 2883–2895. doi:10.1242/jeb.058156. PMID 21832131. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[25] Anderson, W.G. (2005). "Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas". Journal of Experimental Zoology Part A: Comparative Experimental Biology. 303A (10): 917–921. doi:10.1002/jez.a.199. PMID 16161010. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[freshwater-26] Fresh Waters: Unexpected Haunts. elasmo-research.org. Accessed 6 April 2008.

[27] Montoya, Rafael Vasquez (1982). "The bull shark and largetooth sawfish in Lake Bayano, a tropical man-made impoundment in Panama". Env. Biol. Fish. 7 (4): 341–347. doi:10.1007/BF00005568. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[heupel277-28] Heupel, Michelle R. (2008). "Movement and distribution of young bull sharks Carcharhinus leucas in a variable estuarine environment" (PDF). Aqutic Biology. 1: 277–289. doi:10.3354/ab00030. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[29] Life of Bull Shark | Life of Sea. Life-sea.blogspot.com (15 November 2011). Retrieved on 30 November 2013.

[30] "Shark mauls horse in Brisbane River". Sydney Morning Herald. 23 March 2005.

[31] Kindersley, Dorling (2001) in Animal, David Burnie and Don E. Wilson (eds.) London & New York: Smithsonian Institution, ISBN 0789477645.

[32] Bull Sharks, Carcharhinus leucas. Marinebio.org (14 January 2013). Retrieved on 30 November 2013.

[motta131-33] Motta, Philip J (2001). "Advances in the study of feeding behaviors, mechanisms, and mechanics or sharks". Environmental Biology of Fishes. 60 (60): 131–156. doi:10.1023/A:1007649900712. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[Food_Habits-34] Snelson, Franklin F (1). "Food Habits, Occurrence, and Population Structure of the Bull Shark, Carcharhinus Leucas, in Florida Coastal Lagoons". Bulletin of Marine Science. 1: 71–80. {{cite journal}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)

[35] Tuma, Robert E (1976). Investigations of the ichthyofauna of Nicaraguan lakes. American Society of Ichthyologists and Herpetologists.

[McAuley-36] McAuley, R. B. (2007). "Distribution and reproductive biology of the sandbar shark, Carcharhinus plumbeus (Nardo), in Western Australian waters". Mar. Freshwater Res. 58 (1): 116–126. doi:10.1071/MF05234. The proportion of mature males with running spermatozoa increased from 7.1% in October to 79 and 80% in January and March, respectively, suggesting that mating activity peaks during late summer and early autumn. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[Reproduction-37] Jenson, Norman H (1976). "Investigation of the Icthyofauna of Nicaraguan Lakes". American Society of Ichthyologists and Herpetologists. {{cite journal}}: Cite journal requires |journal= (help)

[Behaviour_of_Sharks-38] Bres, M (1993). "The Behaviour of Sharks" (PDF). Reviews in Fish Biology and Fisheries. 3 (2): 133–159. doi:10.1007/BF00045229.

[heupel289-39] Heupel, Michelle R. (14 May). "Shark nursery areas: concepts, definitoin characterization and assumptions". Marine: Ecology Progress Series. 337: 289–297. doi:10.3354/meps337287. {{cite journal}}: Check date values in: |date= and |year= / |date= mismatch (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)

[40] Pacific Shark Research Center » Featured Elasmobranch – Bull Shark. Psrc.mlml.calstate.edu (16 February 2009). Retrieved on 30 November 2013.

[sharkinfo1-41] Fact Sheet: Bull Sharks. Sharkinfo.ch (15 October 1999). Retrieved on 30 November 2013.

[42] Bull Shark – Animal Facts and Information. Bioexpedition.com. Retrieved on 30 November 2013.

[NGEO-43] Handwerk, Brian. "Great Whites May Be Taking the Rap for Bull Shark Attacks". National Geographic News. Retrieved 1 February 2007.

[44] Quinn, Ben (15 March 2009). "Shark attacks bring panic to Sydney's shore". The Guardian. London. Retrieved November 2009. {{cite news}}: Check date values in: |accessdate= (help)

[45] Frantz, Vickie (18 July 2011). "Bull Sharks Attacks Comonly in Warm, Shallow Waters". accuweather.

[autogenerated133-46] Bres, M. (1993). "The behaviour of sharks". Reviews in Fish Bviology and Fisheries. 3 (2): 133–159. doi:10.1007/BF00045229.

[ortega361-47] Ortega, Lori A. (2009). "Movement patterns and water quality preferences of juvenile bull sharks (Carcharhinus lecuas) in a Florida estuary". Evionrmen Biol Fish. 84 (4): 361–373. doi:10.1007/s10641-009-9442-2. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

[Croc_Eat_Shark-48] "No Bull: Saltwater Crocodile Eats Shark". UnderwaterTimes.com. 13 August 2007. Retrieved 15 June 2008.

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@@ Line 1: / Line 1: @@
+{{Use dmy dates|date=November 2013}}
 {{Taxobox
 | name = Bull shark
@@ Line 21: / Line 22: @@
 | range_map_caption = Range of bull shark
 |}}
-The '''bull shark''', ''Carcharhinus leucas'', also known as the '''Zambezi shark''' or unofficially '''Zambi''' in Africa and '''Nicaragua shark''' in [[Nicaragua]], is a [[shark]] commonly found worldwide in warm, shallow waters along coasts and in rivers. The bull shark is known for its aggressive nature, predilection for warm shallow water, and presence in [[Brackish water|brackish]] and freshwater systems including [[estuaries]] and rivers.
+The '''bull shark''' (''Carcharhinus leucas''), also known as the '''Zambezi shark''' or unofficially '''Zambi''' in Africa and '''Nicaragua shark''' in [[Nicaragua]], is a [[shark]] commonly found worldwide in warm, shallow waters along coasts and in rivers. The bull shark is known for its aggressive nature, predilection for warm shallow water, and presence in [[Brackish water|brackish]] and freshwater systems including [[estuaries]] and rivers.
-The bull shark can thrive in both saltwater and freshwater and can travel far up rivers. They have even been known to travel as far up the [[Mississippi River]] as [[Illinois]], and in the [[Ohio River]], <ref>[http://www.in-fisherman.com/2012/07/16/sharks-in-illinois/ Sharks In Illinois]. In-Fisherman (2012-07-16). Retrieved on 2013-11-30.</ref> although there have been few recorded freshwater attacks. They are probably responsible for the majority of near-shore [[shark attack]]s, including many attacks attributed to other species.<ref name="FLMNH">{{cite web|url=http://www.flmnh.ufl.edu/fish/Gallery/Descript/bullshark/bullshark.htm|title=Bull shark|publisher=Florida Museum of Natural History|accessdate=2006-09-08}}</ref>
+The bull shark can thrive in both saltwater and freshwater and can travel far up rivers. They have even been known to travel as far up the [[Mississippi River]] as [[Illinois]], and in the [[Ohio River]], <ref>[http://www.in-fisherman.com/2012/07/16/sharks-in-illinois/ Sharks In Illinois]. In-Fisherman (16 July 2012). Retrieved on 30 November 2013.</ref> although there have been few recorded freshwater attacks. They are probably responsible for the majority of near-shore [[shark attack]]s, including many attacks attributed to other species.<ref name="FLMNH">{{cite web|url=http://www.flmnh.ufl.edu/fish/Gallery/Descript/bullshark/bullshark.htm|title=Bull shark|publisher=Florida Museum of Natural History|accessdate=8 September 2006}}</ref>
 Bull sharks are not actually true freshwater sharks, despite their ability to survive in freshwater habitats (unlike the [[river shark]]s of the genus ''[[Glyphis (shark)|Glyphis]]'').
 ==Etymology==
-The name, bull shark, comes from the shark's stocky shape, broad, flat snout, and aggressive, unpredictable behavior.<ref name=NatGeo/> In [[India]], the bull shark may be confused with the Sundarbans or [[Ganges shark]]. In [[Africa]], it is also commonly called the [[Zambezi|Zambezi River]] shark or just Zambi. Its wide range and diverse habitats result in many other local names, including Ganges River shark, Fitzroy Creek whaler, van Rooyen’s shark, Lake Nicaragua shark,<ref name="elasmo">{{cite web |url=http://www.elasmo-research.org/education/ecology/fresh-bull.htm |title=Biology of Sharks and Rays |publisher=ReefQuest Centre for Shark Research |accessdate=2010-08-19 }}</ref> river shark, freshwater whaler, estuary whaler, Swan River whaler,<ref>{{cite web |url=http://australianmuseum.net.au/Bull-Shark-Carcharhinus-leucas-Valenciennes-1839 |title=Bull Shark, Carcharhinus leucas Valenciennes, 1839 – Australian Museum |publisher=Australian Museum |author=McGrouther, Mark |date=12 May 2010 |accessdate=2010-08-19 }}</ref> cub shark, and shovelnose shark.<ref name="Allen">{{cite book|author=Allen, Thomas B.|title=The Shark Almanac|publisher=New York: The Lyons Press|year=1999|isbn=1-55821-582-4}}</ref>
+The name, bull shark, comes from the shark's stocky shape, broad, flat snout, and aggressive, unpredictable behavior.<ref name=NatGeo/> In [[India]], the bull shark may be confused with the Sundarbans or [[Ganges shark]]. In [[Africa]], it is also commonly called the [[Zambezi|Zambezi River]] shark or just Zambi. Its wide range and diverse habitats result in many other local names, including Ganges River shark, Fitzroy Creek whaler, van Rooyen’s shark, Lake Nicaragua shark,<ref name="elasmo">{{cite web |url=http://www.elasmo-research.org/education/ecology/fresh-bull.htm |title=Biology of Sharks and Rays |publisher=ReefQuest Centre for Shark Research |accessdate=19 August 2010 }}</ref> river shark, freshwater whaler, estuary whaler, Swan River whaler,<ref>{{cite web |url=http://australianmuseum.net.au/Bull-Shark-Carcharhinus-leucas-Valenciennes-1839 |title=Bull Shark, Carcharhinus leucas Valenciennes, 1839 – Australian Museum |publisher=Australian Museum |author=McGrouther, Mark |date=12 May 2010 |accessdate=19 August 2010 }}</ref> cub shark, and shovelnose shark.<ref name="Allen">{{cite book|author=Allen, Thomas B.|title=The Shark Almanac|publisher=New York: The Lyons Press|year=1999|isbn=1-55821-582-4}}</ref>
 ==Anatomy and appearance==
@@ Line 34: / Line 35: @@
 [[File:Bull shark.png|right|thumb|A sketch of a bull shark]]
-Bull sharks are large and stout, with females being larger than males. The bull shark can be up to {{convert|81|cm|ft|abbr=on}} in length at birth.<ref name="Bull Shark SDM">{{cite journal|url=http://www.sharkdivermag.com/issue17-bull-shark.html |title=Shark Species; Bull Sharks|journal=Shark Diver Magazine|volume= 17|year= 2003|pages=34}}</ref> Adult female bull sharks average {{convert|2.4|m|ft|abbr=on}} long and typically weigh {{convert|130|kg|lb|abbr=on}}, whereas the slightly smaller adult male averages {{convert|2.25|m|ft|abbr=on}} and {{convert|95|kg|lb|abbr=on}}. While a maximum size of {{convert|3.5|m|ft|abbr=on}} is commonly reported, there is a questionable record of a female specimen of exactly {{convert|4|m|ft|abbr=on}}. The maximum recorded weight of a bull shark was {{convert|315|kg|lb|abbr=on}} but may be larger.<ref name="FLMNH"/><ref>{{cite web|url=http://www.rsmas.miami.edu/blog/2012/07/18/the-biggest-bull-sharkever/ |title=The Rosenstiel School of Marine & Atmospheric Science}}}</ref><ref>{{cite web|url=http://www.totalprosports.com/2011/08/04/9-biggest-sharks-ever-caught/#2 |title=9 Biggest Sharks Ever Caught |work=Total Pro Sports.com}}}</ref> Bull sharks are wider and heavier than other [[requiem shark]]s of comparable length, and are grey on top and white below. The second [[dorsal fin]] is smaller than the first. The bull shark's [[caudal fin]] is longer and lower than that of the larger sharks, it also has a small [[snout]], and it lacks an interdorsal ridge.<ref name="Bull Shark SDM" />
+Bull sharks are large and stout, with females being larger than males. The bull shark can be up to {{convert|81|cm|ft|abbr=on}} in length at birth.<ref name="Bull Shark SDM">{{cite journal|url=http://www.sharkdivermag.com/issue17-bull-shark.html |title=Shark Species; Bull Sharks|journal=Shark Diver Magazine|volume= 17|year= 2003|page=34}}</ref> Adult female bull sharks average {{convert|2.4|m|ft|abbr=on}} long and typically weigh {{convert|130|kg|lb|abbr=on}}, whereas the slightly smaller adult male averages {{convert|2.25|m|ft|abbr=on}} and {{convert|95|kg|lb|abbr=on}}. While a maximum size of {{convert|3.5|m|ft|abbr=on}} is commonly reported, there is a questionable record of a female specimen of exactly {{convert|4|m|ft|abbr=on}}. The maximum recorded weight of a bull shark was {{convert|315|kg|lb|abbr=on}} but may be larger.<ref name="FLMNH"/><ref>{{cite web|url=http://www.rsmas.miami.edu/blog/2012/07/18/the-biggest-bull-sharkever/ |title=The Rosenstiel School of Marine & Atmospheric Science}}}</ref><ref>{{cite web|url=http://www.totalprosports.com/2011/08/04/9-biggest-sharks-ever-caught/#2 |title=9 Biggest Sharks Ever Caught |work=Total Pro Sports.com}}}</ref> Bull sharks are wider and heavier than other [[requiem shark]]s of comparable length, and are grey on top and white below. The second [[dorsal fin]] is smaller than the first. The bull shark's [[caudal fin]] is longer and lower than that of the larger sharks, it also has a small [[snout]], and it lacks an interdorsal ridge.<ref name="Bull Shark SDM" />
 Bull sharks have a bite force of up to {{convert|600|kg|lbs}}, pound for pound the highest among all investigated cartilaginous fishes.<ref>{{cite doi |10.1016/j.zool.2012.04.007}}; for a popular summary, see {{cite web |url=http://www.bbc.co.uk/nature/19869336 |title=Bull sharks have strongest bite of all shark species |author=Walker, Matt |date=12 October 2012 |work=BBC News |accessdate=12 October 2012}}</ref>
@@ Line 43: / Line 44: @@
 |title=''Carcharhinus leucas''|author=Crist, Rick
 |publisher=University of Michigan Museum of Zoology, Animal Diversity Web
-|accessdate=2006-09-08}}
+|accessdate=8 September 2006}}
 </ref>  In the [[Atlantic]], it is found from [[Massachusetts]] to southern [[Brazil]], and from [[Morocco]] to [[Angola]]. In the [[Indian Ocean]], it is found from [[South Africa]] to [[Kenya]], [[India]], and [[Vietnam]] to [[Australia]].
-Populations of bull sharks are also found in several major rivers, with more than 500 bull sharks thought to be living in the [[Brisbane River]]. One was reportedly seen swimming the flooded streets of [[Brisbane]], [[Queensland, Australia]], during the Queensland floods of late 2010/early 2011.<ref>{{cite news| url=http://www.bbc.co.uk/news/world-asia-pacific-12169218 | work=BBC News | title=Queensland rebuilding 'huge task' | date=2011-01-12}}</ref> Several were sighted in one of the main streets of [[Goodna]], [[Queensland, Australia]], shortly after the peak of the January, 2011, floods.<ref>[http://www.dailyexaminer.com.au/story/2011/01/14/ipswich-bull-sharks-spotted-flood-affected-streets/ Bull sharks seen in flooded streets | Offbeat | Weird News, Odd and Freaky Stories in Northern Rivers | Clarence Valley Daily Examiner]. Dailyexaminer.com.au (2011-01-14). Retrieved on 2012-05-04.</ref>  There are greater numbers still in the canals of the [[Gold Coast, Queensland|Gold Coast]], also in  [[Queensland, Australia]]. A large bull shark was caught in the canals of [[Scarborough, Queensland|Scarborough]], two hours north of the Gold Coast.<ref>{{cite web | author=Berrett, Nick | title=Canal shark shock | url=http://redcliffe-and-bayside-herald.whereilive.com.au/news/story/canal-shark-shock/ | date=2008-11-14 | work=Redcliffe & Bayside Herald | publisher=[[Quest Community Newspapers]] | accessdate=2009-03-26 }}</ref> In the [[Pacific Ocean]], it can be found from [[Baja California]] to [[Ecuador]].
+Populations of bull sharks are also found in several major rivers, with more than 500 bull sharks thought to be living in the [[Brisbane River]]. One was reportedly seen swimming the flooded streets of [[Brisbane]], [[Queensland, Australia]], during the Queensland floods of late 2010/early 2011.<ref>{{cite news| url=http://www.bbc.co.uk/news/world-asia-pacific-12169218 | work=BBC News | title=Queensland rebuilding 'huge task' | date=12 January 2011}}</ref> Several were sighted in one of the main streets of [[Goodna]], [[Queensland, Australia]], shortly after the peak of the January 2011, floods.<ref>[http://www.dailyexaminer.com.au/story/2011/01/14/ipswich-bull-sharks-spotted-flood-affected-streets/ Bull sharks seen in flooded streets | Offbeat | Weird News, Odd and Freaky Stories in Northern Rivers | Clarence Valley Daily Examiner]. Dailyexaminer.com.au (14 January 2011). Retrieved on 4 May 2012.</ref>  There are greater numbers still in the canals of the [[Gold Coast, Queensland|Gold Coast]], also in  [[Queensland, Australia]]. A large bull shark was caught in the canals of [[Scarborough, Queensland|Scarborough]], two hours north of the Gold Coast.<ref>{{cite web | author=Berrett, Nick | title=Canal shark shock | url=http://redcliffe-and-bayside-herald.whereilive.com.au/news/story/canal-shark-shock/ | date=14 November 2008 | work=Redcliffe & Bayside Herald | publisher=[[Quest Community Newspapers]] | accessdate=26 March 2009 }}</ref> In the [[Pacific Ocean]], it can be found from [[Baja California]] to [[Ecuador]].
 The shark has traveled {{convert|4000|km}} up the [[Amazon River]] to [[Iquitos]] in [[Peru]].<ref>[http://web.archive.org/web/20110714165653/http://sharks-med.netfirms.com/med/bull.htm Shark Gallery. Bull shark (''Carcharhinus leucas'')]. sharks-med.netfirms.com</ref> It also lives in fresh water [[Lake Nicaragua]], in the [[Ganges]] and [[Brahmaputra]] rivers of [[West Bengal]] and [[Assam]] in eastern [[India]] and adjoining [[Bangladesh]]. It can live in water with a high salt content as in [[iSimangaliso Wetland Park|St. Lucia Estuary]] in [[South Africa]]. The bull shark is generally prolific in the warm coastal waters and estuarine systems of the [[Mozambique Channel]] and southward, including [[Kwa-Zulu Natal]] and [[Mozambique]]. The species has a distinct preference for warm currents.
-After [[Hurricane Katrina]], many bull sharks were sighted in [[Lake Pontchartrain]].<ref>[http://www.wwltv.com/local/stories/wwl091606tpsharks.1619bc93.html High number of sharks reported in Lake Pontchartrain]</ref> Bull sharks have occasionally gone up the [[Mississippi River]] as far upstream as [[Alton, Illinois]].<ref>
+After [[Hurricane Katrina]], many bull sharks were sighted in [[Lake Pontchartrain]].<ref>[http://web.archive.org/web/20071016151724/http://wwltv.com/local/stories/wwl091606tpsharks.1619bc93.htmll High number of sharks reported in Lake Pontchartrain]. wwltv.com. 16 September 2006</ref> Bull sharks have occasionally gone up the [[Mississippi River]] as far upstream as [[Alton, Illinois]].<ref>
 {{cite web
 |url=http://www.in-fisherman.com/content/sharks-illinois
 |title=''Sharks in Illinois''
 |publisher=In-Fisherman
-|accessdate=2010-07-26}}
+|accessdate=26 July 2010}}
-</ref> They have also been found in the [[Potomac River]] in [[Maryland]].<ref>[http://www.nbcwashington.com/news/local-beat/8-Foot-Shark-Caught-in-Potomac-River-101987408.html 8-Foot Shark Caught In Potomac River]. Nbcwashington.com. Retrieved on 2012-05-04.</ref><ref>{{cite news|last=Zauzmer|first=Julie|title=Man catches 2 bull sharks in Potomac|url=http://www.washingtonpost.com/local/man-catches-2-bull-sharks-in-potomac/2013/08/21/d9cbe9c4-0ad5-11e3-9941-6711ed662e71_story.html?hpid=z2|newspaper=Washington Post|date=August 22}}</ref>
+</ref> They have also been found in the [[Potomac River]] in [[Maryland]].<ref>[http://www.nbcwashington.com/news/local-beat/8-Foot-Shark-Caught-in-Potomac-River-101987408.html 8-Foot Shark Caught In Potomac River]. Nbcwashington.com. Retrieved on 4 May 2012.</ref><ref>{{cite news|last=Zauzmer|first=Julie|title=Man catches 2 bull sharks in Potomac|url=http://www.washingtonpost.com/local/man-catches-2-bull-sharks-in-potomac/2013/08/21/d9cbe9c4-0ad5-11e3-9941-6711ed662e71_story.html?hpid=z2|newspaper=Washington Post|date=22 August 2013}}</ref>
 ==Behavior==
 ===Freshwater tolerance===
-The bull shark is the best known of 43 species of  [[elasmobranch]] in ten genera and four families to have been reported in fresh water.<ref>{{cite web |url=http://www.flmnh.ufl.edu/fish/organizations/ssg/sharknews/sn3/shark3news6.htm |title=Freshwater elasmobranchs; a questionable future |publisher=Florida Museum of Natural History Ichthyology Department |author=Compagno, Leonard I.V. and Cook, Sid F. |month=March |year=1995|accessdate=2011-04-27 }}</ref> Other species that enter rivers include the [[stingrays]] ([[Dasyatidae]], [[Potamotrygonidae]] and others) and [[sawfish]] ([[Pristidae]]).  Some [[skate]]s ([[Rajidae]]), [[smooth dogfish]]es ([[Triakidae]]), and [[sandbar shark]]s (''[[Carcharhinus plumbeus]]'') regularly enter estuaries.  Elasmobranchs' ability to enter fresh water is limited because their blood is normally at least as salty (in terms of [[osmotic strength]]) as seawater through the accumulation of [[urea]] and [[trimethylamine oxide]], but bull sharks living in fresh water  show a significantly reduced concentration of urea within their blood.<ref>{{cite journal|last=Pillans|first=R.D.|coauthors=Franklin, C.E.|title=Plasma osmolyte concentrations and rectal gland mass of bull sharks Carcharhinus leucas, captured along a salinity gradient.|journal=Comparative Biochemistry and Physiology A: Molecular and Integrative Physiology|year=2004|volume=138|issue=3|pages=363–371|pmid=15313492|url=http://www.sciencedirect.com/science/article/pii/S1095643304001564|doi=10.1016/j.cbpb.2004.05.006}}</ref> Despite this, the solute composition (i.e. osmolarity) of a bull shark in freshwater is still much higher than that of the external environment. This results in a large influx of water across the gills due to osmosis and loss of sodium and chloride from the shark's body. However, bull sharks in freshwater possess several organs with which to maintain appropriate salt and water balance; these are the rectal gland, kidneys, liver and gills. All elasmobranchs have a rectal gland which functions in the excretion of excess salts accumulated as a consequence of living in seawater. Bull sharks in freshwater environments decrease the salt-excretory activity of the rectal gland, thereby conserving sodium and chloride.<ref name="bo">{{cite journal|last=Pillans|first=R.D.|coauthors=Good, J.P., Anderson, W.G., Hazon, N and Franklin, C.E.|title=Freshwater to seawater acclimation of juvenile bull sharks (Carcharhinus leucas ): plasma osmolytes and Na+/K+-ATPase activity in gill, rectal gland, kidney and intestine|journal=Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology|year=2005|volume=175|pages=37–44|pmid=15565307|url=http://www.sciencecollege.com/sharklab/courses/elasmobiology/readings/pillans.pdf|doi=10.1007/s00360-004-0460-2}}</ref> The kidneys produce large amounts of dilute urine, but also play an important role in the active reabsorption of solutes into the blood.<ref name="bo" /> The gills of bull sharks are likely to be involved in the uptake of sodium and chloride from the surrounding freshwater,<ref>{{cite journal|last=Reilly|first=B.D.|coauthors=Cramp, R.L., Wilson, J.M., Campbell, H.A and Franklin, C.E.|title=Branchial osmoregulation in the euryhaline bull shark, Carcharhinus leucas: a molecular analysis of ion transporters.|journal=The Journal of Experimental Biology|year=2011|volume=214|pages=2883–2895|pmid=21832131|url=http://jeb.biologists.org/content/214/17/2883.full.pdf+html?sid=bba8108f-8f97-4204-aea8-f749b3804e37|doi=10.1242/jeb.058156|issue=17}}</ref> whereas urea is produced in the liver as required with changes in environmental salinity.<ref>{{cite journal|last=Anderson|first=W.G.|coauthors=Good,  J.P., Pillans, R.D., Hazon, N and Franklin, C.E.|title=Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas.|journal=Journal of Experimental Zoology Part A: Comparative Experimental Biology|volume=303A|issue=10|pages=917–921|pmid=16161010|url=http://onlinelibrary.wiley.com/doi/10.1002/jez.a.199/abstract|doi=10.1002/jez.a.199}}</ref>
+The bull shark is the best known of 43 species of [[elasmobranch]] in ten genera and four families to have been reported in fresh water.<ref>{{cite web |url=http://web.archive.org/web/20080705162720/http://www.flmnh.ufl.edu/fish/organizations/ssg/sharknews/sn3/shark3news6.htm |title=Freshwater elasmobranchs; a questionable future |publisher=Florida Museum of Natural History Ichthyology Department |author=Compagno, Leonard I.V. and Cook, Sid F. |month=March |year=1995|accessdate=27 April 2011 }}</ref> Other species that enter rivers include the [[stingrays]] ([[Dasyatidae]], [[Potamotrygonidae]] and others) and [[sawfish]] ([[Pristidae]]). Some [[skate]]s ([[Rajidae]]), [[smooth dogfish]]es ([[Triakidae]]), and [[sandbar shark]]s (''[[Carcharhinus plumbeus]]'') regularly enter estuaries.  Elasmobranchs' ability to enter fresh water is limited because their blood is normally at least as salty (in terms of [[osmotic strength]]) as seawater through the accumulation of [[urea]] and [[trimethylamine oxide]], but bull sharks living in fresh water  show a significantly reduced concentration of urea within their blood.<ref>{{cite journal|last=Pillans|first=R.D.|coauthors=Franklin, C.E.|title=Plasma osmolyte concentrations and rectal gland mass of bull sharks Carcharhinus leucas, captured along a salinity gradient.|journal=Comparative Biochemistry and Physiology A: Molecular and Integrative Physiology|year=2004|volume=138|issue=3|pages=363–371|pmid=15313492|url=http://www.sciencedirect.com/science/article/pii/S1095643304001564|doi=10.1016/j.cbpb.2004.05.006}}</ref> Despite this, the solute composition (i.e. osmolarity) of a bull shark in freshwater is still much higher than that of the external environment. This results in a large influx of water across the gills due to osmosis and loss of sodium and chloride from the shark's body. However, bull sharks in freshwater possess several organs with which to maintain appropriate salt and water balance; these are the rectal gland, kidneys, liver and gills. All elasmobranchs have a rectal gland which functions in the excretion of excess salts accumulated as a consequence of living in seawater. Bull sharks in freshwater environments decrease the salt-excretory activity of the rectal gland, thereby conserving sodium and chloride.<ref name="bo">{{cite journal|last=Pillans|first=R.D.|coauthors=Good, J.P., Anderson, W.G., Hazon, N and Franklin, C.E.|title=Freshwater to seawater acclimation of juvenile bull sharks (''Carcharhinus leucas''): plasma osmolytes and Na<sup>+</sup>/K<sup>+</sup>-ATPase activity in gill, rectal gland, kidney and intestine|journal=Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology|year=2005|volume=175|pages=37–44|pmid=15565307|url=http://www.sciencecollege.com/sharklab/courses/elasmobiology/readings/pillans.pdf|doi=10.1007/s00360-004-0460-2|issue=1}}</ref> The kidneys produce large amounts of dilute urine, but also play an important role in the active reabsorption of solutes into the blood.<ref name="bo" /> The gills of bull sharks are likely to be involved in the uptake of sodium and chloride from the surrounding freshwater,<ref>{{cite journal|last=Reilly|first=B.D.|coauthors=Cramp, R.L., Wilson, J.M., Campbell, H.A and Franklin, C.E.|title=Branchial osmoregulation in the euryhaline bull shark, ''Carcharhinus leucas'': a molecular analysis of ion transporters|journal=The Journal of Experimental Biology|year=2011|volume=214|pages=2883–2895|pmid=21832131|url=http://jeb.biologists.org/content/214/17/2883.full.pdf+html?sid=bba8108f-8f97-4204-aea8-f749b3804e37|doi=10.1242/jeb.058156|issue=17}}</ref> whereas urea is produced in the liver as required with changes in environmental salinity.<ref>{{cite journal|last=Anderson|first=W.G.|coauthors=Good, J.P., Pillans, R.D., Hazon, N and Franklin, C.E.|title=Hepatic urea biosynthesis in the euryhaline elasmobranch Carcharhinus leucas|journal=Journal of Experimental Zoology Part A: Comparative Experimental Biology|volume=303A|issue=10|pages=917–921|pmid=16161010|doi=10.1002/jez.a.199|year=2005}}</ref>
-Initially, scientists thought the sharks in [[Lake Nicaragua]] belonged to an [[endemism|endemic]] species, the Lake Nicaragua shark (''Carcharhinus nicaraguensis''). In 1961, following [[Biological specimen|specimen]]s comparisons, taxonomists  [[Synonym (taxonomy)|synonymized]] them.<ref name=freshwater>[http://www.elasmo-research.org/education/ecology/fresh-bull.htm Fresh Waters: Unexpected Haunts.] elasmo-research.org. Accessed 2008-04-06.</ref> They can jump along the rapids of the [[San Juan River (Nicaragua)|San Juan River]] (which connects Lake Nicaragua and the [[Caribbean Sea]]), almost like [[salmon]].<ref name="ADW"/> Bull sharks tagged inside the lake have later been caught in the [[open ocean]] (and ''[[List of Latin phrases: V|vice versa]]''), with some taking as little as seven to eleven days to complete the journey.<ref name=freshwater/>
+Initially, scientists thought the sharks in [[Lake Nicaragua]] belonged to an [[endemism|endemic]] species, the Lake Nicaragua shark (''Carcharhinus nicaraguensis''). In 1961, following [[Biological specimen|specimen]]s comparisons, taxonomists  [[Synonym (taxonomy)|synonymized]] them.<ref name=freshwater>[http://www.elasmo-research.org/education/ecology/fresh-bull.htm Fresh Waters: Unexpected Haunts.] elasmo-research.org. Accessed 6 April 2008.</ref> They can jump along the rapids of the [[San Juan River (Nicaragua)|San Juan River]] (which connects Lake Nicaragua and the [[Caribbean Sea]]), almost like [[salmon]].<ref name="ADW"/> Bull sharks tagged inside the lake have later been caught in the [[open ocean]] (and ''[[List of Latin phrases: V|vice versa]]''), with some taking as little as seven to eleven days to complete the journey.<ref name=freshwater/>
-Bull sharks are able to regulate themselves to live in either fresh water or salt water. It is possible for the bull shark to live in fresh water for its entire life, but it has been observed that this does not happen for certain reasons, mostly due to reproduction. Young bull sharks will leave the brackish water in which they are born and move out into the sea in order to breed with bull sharks of the other sex. While theoretically, it may be possible for bull sharks to live in purely freshwater, it was observed that the bull sharks that were being experimented on had died within four years. The stomach was opened and all that was found were 2 small fishes that were unidentifiable. The cause of death could have been starvation since the primary food source for bull sharks resides in salt water. <ref>{{cite journal|last=Montoya|first=Rafael Vasquez|coauthors=Thorson, Thomas B.|title=The bull shark and largetooth sawfish in Lake Bayano, a tropical man-made impoundment in Panama|journal=Env. Biol. Fish|year=1982|volume=7|issue=4|pages=341-347|url=http://je5qh2yg7p.scholar.serialssolutions.com/?sid=google&auinit=RV&aulast=Montoya&atitle=The+bull+shark+%28Carcharhinus+leucas%29+and+largetooth+sash+%28Pristis+perotteti%29+in+Lake+Bayano,+a+tropical+man-made+impoundment+in+Panama&id=doi:10.1007/BF00005568&title=Environmental+biology+of+fishes&volume=7&issue=4&date=1982&spage=341&issn=0378-1909}}</ref>
+Bull sharks are able to regulate themselves to live in either fresh water or salt water. It is possible for the bull shark to live in fresh water for its entire life, but it has been observed that this does not happen for certain reasons, mostly due to reproduction. Young bull sharks will leave the brackish water in which they are born and move out into the sea in order to breed with bull sharks of the other sex. While theoretically, it may be possible for bull sharks to live in purely freshwater, it was observed that the bull sharks that were being experimented on had died within four years. The stomach was opened and all that was found were 2 small fishes that were unidentifiable. The cause of death could have been starvation since the primary food source for bull sharks resides in salt water. <ref>{{cite journal|last=Montoya|first=Rafael Vasquez|coauthors=Thorson, Thomas B.|title=The bull shark and largetooth sawfish in Lake Bayano, a tropical man-made impoundment in Panama|journal=Env. Biol. Fish|year=1982|volume=7|issue=4|pages=341–347|doi=10.1007/BF00005568}}</ref>
-The bull shark is known to be able to live in both saltwater and freshwater. It is one of the special abilities that the bull shark possesses that dictates how the bull shark is able to breed in safety. it was found in a research experiment that the majority of the time, the bull sharks were found to be at the mouth of an estuary.<ref name="heupel277">{{cite journal|last=Heupel|first=Michelle R.|coauthors=Colin A. Simpfendorfer|title=Movement and distribution of young bull sharks Carcharhinus leucas in a variable estuarine environment|journal=Aqutic Biology|date=2008|volume=1|pages=277-289|url=http://www.int-res.com/articles/ab2007/1/b001p277.pdf}}</ref>  The water salinity was tested every month to test for if the difference in salinity is what drove bull sharks into the river or not. It was found that the bull shark stayed at the mouth of the river independent of the salinity of the water. <ref name="heupel277"/> The driving factor for a bull shark to be in freshwater or saltwater depends on its age because as the bull shark ages, the tolerance for very low or high salinity increases.<ref name="heupel277"/> It was found that the majority of the newborn or very young bull sharks were found in the freshwater area, whereas the much older bull sharks were found to be in the saltwater as they had developed a much better tolerance for the salinity.<ref name="heupel277"/> This is one of the reasons why adult bull sharks will travel into the river in order to have the offspring. The newborns are not born with a high tolerance for high salinity, so they are born in freshwater and stay there until they are able to travel out.
+The bull shark is known to be able to live in both saltwater and freshwater. It is one of the special abilities that the bull shark possesses that dictates how the bull shark is able to breed in safety. it was found in a research experiment that the majority of the time, the bull sharks were found to be at the mouth of an estuary.<ref name="heupel277">{{cite journal|last=Heupel|first=Michelle R.|coauthors=Colin A. Simpfendorfer|title=Movement and distribution of young bull sharks Carcharhinus leucas in a variable estuarine environment|journal=Aqutic Biology|date=2008|volume=1|pages=277–289|url=http://www.int-res.com/articles/ab2007/1/b001p277.pdf|doi=10.3354/ab00030}}</ref>  The water salinity was tested every month to test for if the difference in salinity is what drove bull sharks into the river or not. It was found that the bull shark stayed at the mouth of the river independent of the salinity of the water. <ref name="heupel277"/> The driving factor for a bull shark to be in freshwater or saltwater depends on its age because as the bull shark ages, the tolerance for very low or high salinity increases.<ref name="heupel277"/> It was found that the majority of the newborn or very young bull sharks were found in the freshwater area, whereas the much older bull sharks were found to be in the saltwater as they had developed a much better tolerance for the salinity.<ref name="heupel277"/> This is one of the reasons why adult bull sharks will travel into the river in order to have the offspring. The newborns are not born with a high tolerance for high salinity, so they are born in freshwater and stay there until they are able to travel out.
 ===Diet===
-Bull sharks are typically solitary hunters,<ref name="ADW"/>  but occasionally hunt in pairs.<ref>http://life-sea.blogspot.com/2011/07/life-of-bull-shark.html</ref>  They often cruise through shallow waters, and can accelerate rapidly and be highly aggressive, even possibly attacking a racehorse in the [[Brisbane River]] in the [[Australian]] state of [[Queensland]].<ref>{{cite news  |title=Shark mauls horse in Brisbane River |url=http://www.smh.com.au/news/National/Shark-mauls-horse-in-Brisbane-Rivers/2005/03/23/1111525216327.html |work=[[Sydney Morning Herald]] |date=2005-03-23}}</ref> They are extremely territorial and attack animals that enter their territory.
+Bull sharks are typically solitary hunters,<ref name="ADW"/>  but occasionally hunt in pairs.<ref>[http://life-sea.blogspot.com/2011/07/life-of-bull-shark.html Life of Bull Shark | Life of Sea]. Life-sea.blogspot.com (15 November 2011). Retrieved on 30 November 2013.</ref>  They often cruise through shallow waters, and can accelerate rapidly and be highly aggressive, even possibly attacking a racehorse in the [[Brisbane River]] in the [[Australian]] state of [[Queensland]].<ref>{{cite news  |title=Shark mauls horse in Brisbane River |url=http://www.smh.com.au/news/National/Shark-mauls-horse-in-Brisbane-Rivers/2005/03/23/1111525216327.html |work=[[Sydney Morning Herald]] |date=23 March 2005}}</ref> They are extremely territorial and attack animals that enter their territory.
 The bull shark's diet consists mainly of [[bony fish]] and sharks, including other bull sharks,<ref name="FLMNH"/> but can also include turtles, birds, dolphins, terrestrial mammals, [[crustacean]]s, [[echinoderm]]s, and stingrays. They hunt in murky waters because it is harder for the prey to see the shark coming.<!--DO NOT ADD HUMANS UNLESS YOU CITE A RELIABLE SOURCE THAT CALLS HUMANS PART OF THEIR DIET--><ref name=IUCN/><ref>Kindersley, Dorling (2001) in ''Animal'', David Burnie and Don E. Wilson (eds.) London & New York: Smithsonian Institution, ISBN 0789477645.</ref> Bull sharks have been known to use the [[Shark Attack#Types of attacks|bump-and-bite technique]] to attack their prey.
-The bull shark is known to be a solitary hunter, although there are brief moments in which the bull sharks will team up with another bull shark in order to make it easier to hunt and to trick prey.<ref>http://marinebio.org/species.asp?id=83</ref>
+The bull shark is known to be a solitary hunter, although there are brief moments in which the bull sharks will team up with another bull shark in order to make it easier to hunt and to trick prey.<ref>[http://marinebio.org/species.asp?id=83 Bull Sharks, ''Carcharhinus leucas'']. Marinebio.org (14 January 2013). Retrieved on 30 November 2013.</ref>
-[[Shark]]s are known to be opportunistic when feeding, <ref name="motta131">{{cite journal|last=Motta|first=Philip J|coauthors=Wilga, Cheryl D. |title=Advances in the study of feeding behaviors, mechanisms, and mechanics or sharks|journal=Environmental Biology of Fishes|year=2001|issue=60|pages=131-156}}</ref> and the bull shark is no exception to this, as it is part of the ''Carcharhinus'' family of sharks. Normally, sharks eat in short bursts, and when food is scarce, sharks digest for a much longer period of time in order to avoid starvation.<ref name="motta131"/> The bull shark continues to bite and tackle its prey until the prey is unable to escape, and then the bull shark eats its prey.<ref name="motta131"/>
+[[Shark]]s are known to be opportunistic when feeding, <ref name="motta131">{{cite journal|last=Motta|first=Philip J|coauthors=Wilga, Cheryl D. |title=Advances in the study of feeding behaviors, mechanisms, and mechanics or sharks|journal=Environmental Biology of Fishes|year=2001|issue=60|pages=131–156|doi=10.1023/A:1007649900712|volume=60}}</ref> and the bull shark is no exception to this, as it is part of the ''Carcharhinus'' family of sharks. Normally, sharks eat in short bursts, and when food is scarce, sharks digest for a much longer period of time in order to avoid starvation.<ref name="motta131"/> The bull shark continues to bite and tackle its prey until the prey is unable to escape, and then the bull shark eats its prey.<ref name="motta131"/>
-The bull shark is known to populate the [[Indian River (Florida)|Indian River]]. In Florida, researchers examined the contents of the bull shark's stomach. Stingrays and Ariid catfishes, which are both abundant in the Indian River, were found to be in the stomach of examined bull sharks.<ref name="Food Habits" />  One surprising discovery, the head of a small shark, was found, suggesting that the bull shark is capable of feeding upon other sharks in addition to the other fish that it preys on. <ref name="Food Habits">{{cite journal|last=Snelson|first=Franklin F|coauthors=Mulligan, Timothy J, Williams, Sherry E.|title=Food Habits, Occurrence, and Population Structure of the Bull Shark, Carcharhinus Leucas, in Florida Coastal Lagoons|journal=Bulletin of Marine Science|date=1|year=1984|month=January|volume=1|pages=71-80}}</ref>
+The bull shark is known to populate the [[Indian River (Florida)|Indian River]]. In Florida, researchers examined the contents of the bull shark's stomach. Stingrays and Ariid catfishes, which are both abundant in the Indian River, were found to be in the stomach of examined bull sharks.<ref name="Food Habits" />  One surprising discovery, the head of a small shark, was found, suggesting that the bull shark is capable of feeding upon other sharks in addition to the other fish that it preys on. <ref name="Food Habits">{{cite journal|last=Snelson|first=Franklin F|coauthors=Mulligan, Timothy J, Williams, Sherry E.|title=Food Habits, Occurrence, and Population Structure of the Bull Shark, Carcharhinus Leucas, in Florida Coastal Lagoons|journal=Bulletin of Marine Science|date=1|year=1984|month=January|volume=1|pages=71–80}}</ref>
-It also has been cited in the [[San Juan River]] area, that the bull shark had consumed sharks. Vorenburg induced a "shark eat shark" environment in which lemon sharks and bull sharks were put into an environment where they had to fight for food, and the injured sharks from the bouts were consumed by the bull sharks. In addition to lemon sharks, they also fed on young sandbar sharks. There has been no evidence to prove that there are different feeding patterns among young and adults or among males and females. Bull sharks do not actively seek out food, but rather are dependent on anything that is available to them. As part of their survival mechanism, bull sharks will regurgitate the food in their stomachs in order to escape from a predator as they stop for the regurgitated food.<ref>{{cite journal|last=Tuma|first=Robert E|title=An Investigation of the Feedin gHabits of the Bull Shkar, Carcharhinus leucas, in the Lake Nicaragua-Rio San Juan System|journal=Investigations of the Icthyofauna of Nicraraguan Lake|date=1-1-1976|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1038&context=ichthynicar&sei-redir=1&referer=http%3A%2F%2Fscholar.google.com%2Fscholar%3Fhl%3Den%26q%3Dbull%2Bshark%2Bfeeding%26btnG%3D%26as_sdt%3D1%252C26%26as_sdtp%3D#search=%22bull%20shark%20feeding%22}}</ref>
+It also has been cited in the [[San Juan River]] area, that the bull shark had consumed sharks. Vorenburg induced a "shark eat shark" environment in which lemon sharks and bull sharks were put into an environment where they had to fight for food, and the injured sharks from the bouts were consumed by the bull sharks. In addition to lemon sharks, they also fed on young sandbar sharks. There has been no evidence to prove that there are different feeding patterns among young and adults or among males and females. Bull sharks do not actively seek out food, but rather are dependent on anything that is available to them. As part of their survival mechanism, bull sharks will regurgitate the food in their stomachs in order to escape from a predator as they stop for the regurgitated food.<ref>{{cite book|last=Tuma|first=Robert E|title=Investigations of the ichthyofauna of Nicaraguan lakes|date=1976|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1038&context=ichthynicar&sei-redir=1&referer=http%3A%2F%2Fscholar.google.com%2Fscholar%3Fhl%3Den%26q%3Dbull%2Bshark%2Bfeeding%26btnG%3D%26as_sdt%3D1%252C26%26as_sdtp%3D#search=%22bull%20shark%20feeding%22|publisher=American Society of Ichthyologists and Herpetologists}}</ref>
 ===Reproduction===
-Bull sharks mate during late summer and early autumn,<ref name=McAuley>{{Cite journal| doi = 10.1071/MF05234| volume = 58| issue = 1| pages = 116–126 | last = McAuley| first = R. B. | coauthors = Simpfendorfer, C. A.; Hyndes, G. A. and Lenanton, R. C. J.| title = Distribution and reproductive biology of the sandbar shark, ''Carcharhinus plumbeus'' (Nardo), in Western Australian waters| journal = Mar. Freshwater Res.| accessdate = 2 December 2009| date = 30 January 2007| url = http://www.publish.csiro.au/view/journals/dsp_journal_fulltext.cfm?nid=126&f=MF05234|quote=The proportion of mature males with running spermatozoa increased from 7.1% in October to 79 and 80% in January and March, respectively, suggesting that mating activity peaks during late summer and early autumn.}}</ref> often in the [[brackish]] water of river mouths. After [[Gestation|gestating]] for 12 months, a bull shark may give birth to four to ten live young.<ref name=McAuley/> They are [[viviparous]]; they are born live and free-swimming. The young are about {{convert|70|cm|in|1|abbr=on}} at birth and take 10 years to reach maturity. Coastal lagoons, river mouths, and other low-salinity estuaries are common nursery habitats.<ref name="FLMNH"/>
+Bull sharks mate during late summer and early autumn,<ref name=McAuley>{{Cite journal| doi=10.1071/MF05234| volume = 58| issue = 1| pages = 116–126 | last = McAuley| first = R. B. | coauthors = Simpfendorfer, C. A.; Hyndes, G. A. and Lenanton, R. C. J.| title = Distribution and reproductive biology of the sandbar shark, ''Carcharhinus plumbeus'' (Nardo), in Western Australian waters| journal = Mar. Freshwater Res.|year=2007|quote=The proportion of mature males with running spermatozoa increased from 7.1% in October to 79 and 80% in January and March, respectively, suggesting that mating activity peaks during late summer and early autumn.}}</ref> often in the [[brackish]] water of river mouths. After [[Gestation|gestating]] for 12 months, a bull shark may give birth to four to ten live young.<ref name=McAuley/> They are [[viviparous]]; they are born live and free-swimming. The young are about {{convert|70|cm|in|1|abbr=on}} at birth and take 10 years to reach maturity. Coastal lagoons, river mouths, and other low-salinity estuaries are common nursery habitats.<ref name="FLMNH"/>
-cm to 235 cm seems to be the size of a fully matured female bull shark that produce viable eggs for fertilization. The courting routine between bull sharks has not been observed in detail as of yet. It is speculated that the male bites the females on the tail until they turn upside down and they male can copulate at that point. At some points, the harassment of the male can become violent. It is not uncommon to see scratches and other marks on a mature female from the mating ritual.<ref name=Reproduction>{{cite journal|last=Jenson|first=Norman H|title=Reproduction fothe BUll Shark, Carcharhinus leucas, in the Lake Nicaragua-Rio San Juan System|journal=Investigation of the Icthyofauna of Nicaraguan Lakes|date=1-1-1976|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1039&context=ichthynicar&sei-redir=1&referer=http%3A%2F%2Fscholar.google.com%2Fscholar%3Fstart%3D10%26q%3Dbull%2Bshark%2B%26hl%3Den%26as_sdt%3D0%2C26#search=%22bull%20shark%22}}</ref>
+cm to 235 cm seems to be the size of a fully matured female bull shark that produce viable eggs for fertilization. The courting routine between bull sharks has not been observed in detail as of yet. It is speculated that the male bites the females on the tail until they turn upside down and they male can copulate at that point. At some points, the harassment of the male can become violent. It is not uncommon to see scratches and other marks on a mature female from the mating ritual.<ref name=Reproduction>{{cite journal|last=Jenson|first=Norman H|title=Investigation of the Icthyofauna of Nicaraguan Lakes|publisher=American Society of Ichthyologists and Herpetologists|date=1976|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1039&context=ichthynicar&sei-redir=1&referer=http%3A%2F%2Fscholar.google.com%2Fscholar%3Fstart%3D10%26q%3Dbull%2Bshark%2B%26hl%3Den%26as_sdt%3D0%2C26#search=%22bull%20shark%22}}</ref>
-Bull sharks have an unusual migratory pattern in comparison to other sharks. They are found in rivers all over the world. They have the ability to go from seawater and freshwater. They give birth in the freshwater of rivers. The young bull sharks are free from predators while they grow up in the river before they go out to the sea in order to find mates.<ref name="Behaviour of Sharks">{{cite journal|last=Bres|first=M|title=The Behaviour of Sharks|journal=Reviews in Fish Biology and Fisheries|year=1993|volume=3|pages=133-159|url=http://www.imensidao.net/Downloads/Bres_1993_behaviour_sharks.pdf}}</ref>
+Bull sharks have an unusual migratory pattern in comparison to other sharks. They are found in rivers all over the world. They have the ability to go from seawater and freshwater. They give birth in the freshwater of rivers. The young bull sharks are free from predators while they grow up in the river before they go out to the sea in order to find mates.<ref name="Behaviour of Sharks">{{cite journal|last=Bres|first=M|title=The Behaviour of Sharks|journal=Reviews in Fish Biology and Fisheries|year=1993|volume=3|pages=133–159|url=http://www.imensidao.net/Downloads/Bres_1993_behaviour_sharks.pdf|doi=10.1007/BF00045229|issue=2}}</ref>
-The ability to be able to survive in both freshwater and saltwater also gives another benefit that has been driven by evolution. Because the majority of sharks are only able to survive in saltwater, the bull shark has evolved to have their offspring in the freshwater where other sharks cannot enter.<ref name="heupel289">{{cite journal|last=Heupel|first=Michelle R.|coauthors=Carlson, John K. and Simpfendorfer, Colin A. |title=Shark nursery areas: concepts, definitoin characterization and assumptions|journal=Marine: Ecology Progress Series|date=May 14|year=2007|volume=337|pages=289-297}}</ref>  The freshwater acts as a protective area where the young are able to grow and mature without the threat of larger sharks preying on the younger bull sharks.<ref name="heupel289"/> This is an explanation for the behavior that is observed from the bull sharks as to why there would be any reason for the adult bull shark to ever travel into a freshwater area despite being able to tolerate the high salinity of marine water.
+The ability to be able to survive in both freshwater and saltwater also gives another benefit that has been driven by evolution. Because the majority of sharks are only able to survive in saltwater, the bull shark has evolved to have their offspring in the freshwater where other sharks cannot enter.<ref name="heupel289">{{cite journal|last=Heupel|first=Michelle R.|coauthors=Carlson, John K. and Simpfendorfer, Colin A. |title=Shark nursery areas: concepts, definitoin characterization and assumptions|journal=Marine: Ecology Progress Series|date=14 May|year=2007|volume=337|pages=289–297|doi=10.3354/meps337287}}</ref>  The freshwater acts as a protective area where the young are able to grow and mature without the threat of larger sharks preying on the younger bull sharks.<ref name="heupel289"/> This is an explanation for the behavior that is observed from the bull sharks as to why there would be any reason for the adult bull shark to ever travel into a freshwater area despite being able to tolerate the high salinity of marine water.
-Bull sharks are born alive in freshwater which is in contrast to most sharks since they lay eggs. The average litter for a female bull shark is around 1 to 13 pups.<ref>http://psrc.mlml.calstate.edu/2009/02/285/</ref>  The average time span for a female bull shark to be pregnant is around 10 to 11 months.<ref name="sharkinfo1">http://www.sharkinfo.ch/SI3_99e/cleucas.html</ref> The male bull shark is able to begin reproducing around the age of 15 years while the female cannot begin reproducing until the age of 18 years.<ref name="sharkinfo1"/> Unlike most sharks though, the bull shark does not rear their young like other sharks, the young bull sharks are born into flat, protected areas.<ref name="sharkinfo1"/> Freshwater presents a natural defense against most larger predators, and the flat land is an added defense as most large predators will not swim in shallow areas. This increases their chance of survival since the parents do not rear the young in the traditional manner. This is also the reason why there is a high mortality rate in young bull sharks. Since the parents do not rear and protect the young, any predator that is able to attack a young bull shark is easily able to kill and eat the young bull shark without much resistance.<ref>http://bioexpedition.com/bull-shark/</ref>
+Bull sharks are born alive in freshwater which is in contrast to most sharks since they lay eggs. The average litter for a female bull shark is around 1 to 13 pups.<ref>[http://psrc.mlml.calstate.edu/2009/02/285/ Pacific Shark Research Center » Featured Elasmobranch – Bull Shark]. Psrc.mlml.calstate.edu (16 February 2009). Retrieved on 30 November 2013.</ref>  The average time span for a female bull shark to be pregnant is around 10 to 11 months.<ref name="sharkinfo1">[http://www.sharkinfo.ch/SI3_99e/cleucas.html Fact Sheet: Bull Sharks]. Sharkinfo.ch (15 October 1999). Retrieved on 30 November 2013.</ref> The male bull shark is able to begin reproducing around the age of 15 years while the female cannot begin reproducing until the age of 18 years.<ref name="sharkinfo1"/> Unlike most sharks though, the bull shark does not rear their young like other sharks, the young bull sharks are born into flat, protected areas.<ref name="sharkinfo1"/> Freshwater presents a natural defense against most larger predators, and the flat land is an added defense as most large predators will not swim in shallow areas. This increases their chance of survival since the parents do not rear the young in the traditional manner. This is also the reason why there is a high mortality rate in young bull sharks. Since the parents do not rear and protect the young, any predator that is able to attack a young bull shark is easily able to kill and eat the young bull shark without much resistance.<ref>[http://bioexpedition.com/bull-shark/ Bull Shark – Animal Facts and Information]. Bioexpedition.com. Retrieved on 30 November 2013.</ref>
 ===Interactions with humans===
-[[File:Bullshark.JPG|2thumb|Bull shark (Bahamas)|alt=Photo of bull shark in shallow water]]
+[[File:Bullshark.JPG|thumb|Bull shark (Bahamas)|alt=Photo of bull shark in shallow water]]
-Since bull sharks often dwell in very shallow waters, they may be more dangerous to humans than any other species of shark,<ref name="ADW"/> and along with the [[tiger shark]], [[oceanic whitetip]] and [[great white shark]], are among the four shark species most likely to attack humans.<ref name=NatGeo>{{cite web|url=http://animals.nationalgeographic.com/animals/fish/bull-shark.html|title=Bull shark|publisher=National Geographic|accessdate=2011-04-03}}</ref>
+Since bull sharks often dwell in very shallow waters, they may be more dangerous to humans than any other species of shark,<ref name="ADW"/> and along with the [[tiger shark]], [[oceanic whitetip]] and [[great white shark]], are among the four shark species most likely to attack humans.<ref name=NatGeo>{{cite web|url=http://animals.nationalgeographic.com/animals/fish/bull-shark.html|title=Bull shark|publisher=National Geographic|accessdate=3 April 2011}}</ref>
-One or several bull sharks may have been responsible for the [[Jersey Shore shark attacks of 1916]], which were the inspiration for [[Peter Benchley]]'s novel ''[[Jaws (novel)|Jaws]]''.<ref name="NGEO">{{cite web|url=http://news.nationalgeographic.com/news/2002/08/0802_020802_shark.html|title=Great Whites May Be Taking the Rap for Bull Shark Attacks|author=Handwerk, Brian|publisher=National Geographic News|accessdate=2007-02-01}}</ref> The speculation of bull sharks possibly being responsible is based on some attacks occurring in brackish and freshwater.
+One or several bull sharks may have been responsible for the [[Jersey Shore shark attacks of 1916]], which were the inspiration for [[Peter Benchley]]'s novel ''[[Jaws (novel)|Jaws]]''.<ref name="NGEO">{{cite web|url=http://news.nationalgeographic.com/news/2002/08/0802_020802_shark.html|title=Great Whites May Be Taking the Rap for Bull Shark Attacks|author=Handwerk, Brian|publisher=National Geographic News|accessdate=1 February 2007}}</ref> The speculation of bull sharks possibly being responsible is based on some attacks occurring in brackish and freshwater.
 The bull shark is responsible for attacks around the [[Port Jackson|Sydney Harbour]] inlets.<ref>
@@ Line 109: / Line 110: @@
 }}</ref> Most of these attacks were previously attributed to great white sharks. In India, bull sharks swim up the [[Ganges River]] and have attacked people. Many of these attacks have been attributed to the [[Ganges shark]], ''Glyphis gangeticus'', a critically endangered river shark species that is probably the only other shark in India able to survive in fresh water, although the [[sand tiger shark]] was also blamed during the 1960s and 1970s.
-The bull shark prefers coastal water which is less than 100 feet in depth. This is mostly due to their feeding patterns since they prefer murky waters. This is also a problem since this gives the most interaction with humans. It is known that bull sharks inhabit areas off the coast of Florida, and there have been reports of bull sharks getting close enough to the coast to attack humans since the bull shark is a territorial animal.<ref>{{cite news|last=Frantz|first=Vickie|title=Bull Sharks Attacks Comonly in Warm, Shallow Waters|url=http://www.accuweather.com/en/weather-news/bull-shark-attacks-commonly-in/52515|newspaper=accuweather|date=July 18, 2011}}</ref>
+The bull shark prefers coastal water which is less than 100 feet in depth. This is mostly due to their feeding patterns since they prefer murky waters. This is also a problem since this gives the most interaction with humans. It is known that bull sharks inhabit areas off the coast of Florida, and there have been reports of bull sharks getting close enough to the coast to attack humans since the bull shark is a territorial animal.<ref>{{cite news|last=Frantz|first=Vickie|title=Bull Sharks Attacks Comonly in Warm, Shallow Waters|url=http://www.accuweather.com/en/weather-news/bull-shark-attacks-commonly-in/52515|newspaper=accuweather|date=18 July 2011}}</ref>
 ===Visual cues===
-Behavioral studies have confirmed that sharks can take visual cues in order to discriminate between different objects.<ref name="autogenerated133">{{cite journal|last=Bres|first=M.|title=The behaviour of sharks|journal=Reviews in Fish Bviology and Fisheries|year=1993|volume=3|pages=133-159}}</ref>  The bull shark is able to discriminate between colors of mesh netting that is present underwater. <ref name="autogenerated133"/> It was found that bull sharks tended to avoid mesh netting of bright colors rather than colors that blended in with the water. Bright yellow mesh netting was found to be easily avoided when it was placed in the path of the bull shark. This was found to be the reason that sharks are attracted to bright yellow survival gear rather than ones that were painted black. <ref name="autogenerated133"/> This is very important because it gives an insight into how bull sharks are able to pick up certain visual keys underwater that might give them an advantage when seeking out certain prey.
+Behavioral studies have confirmed that sharks can take visual cues in order to discriminate between different objects.<ref name="autogenerated133">{{cite journal|last=Bres|first=M.|title=The behaviour of sharks|journal=Reviews in Fish Bviology and Fisheries|year=1993|volume=3|pages=133–159|doi=10.1007/BF00045229|issue=2}}</ref>  The bull shark is able to discriminate between colors of mesh netting that is present underwater. <ref name="autogenerated133"/> It was found that bull sharks tended to avoid mesh netting of bright colors rather than colors that blended in with the water. Bright yellow mesh netting was found to be easily avoided when it was placed in the path of the bull shark. This was found to be the reason that sharks are attracted to bright yellow survival gear rather than ones that were painted black. <ref name="autogenerated133"/> This is very important because it gives an insight into how bull sharks are able to pick up certain visual keys underwater that might give them an advantage when seeking out certain prey.
 ===Energy conservation===
-In 2008, researchers tagged and recorded the movements of young bull sharks in the Caloosahatchee River estuary. Specifically, they were testing to find out what determined the movement of the young bull sharks.<ref name="ortega361">{{cite journal|last=Ortega|first=Lori A.|coauthors=Heupel, Michelle R.; van Beynen, Philip and Motta, Philip J. |title=Movement patterns and water quality preferences of juvenile bull sharks (''Carcharhinus lecuas'') in a Florida estuary|journal=Evionrmen Biol Fish|year=2009|volume=84|pages=361-373}}</ref>  It was found that the young bull sharks synchronously moved downriver when the environmental conditions changed.<ref name="ortega361"/>  This large movement of young bull sharks were found to be moving as a response rather than other external factors such as predators. An interesting find was that the movement was directly related to the bull shark conserving energy for itself. One way the bull shark is able to conserve energy is that when the tidal flow changes, the bull shark uses the tidal flow in order to conserve energy as it moves downriver.<ref name="ortega361"/>  Another way for the bull shark to conserve energy is to decrease the amount of energy needed to osmoregulate the surrounding environment.<ref name="ortega361"/>
+In 2008, researchers tagged and recorded the movements of young bull sharks in the Caloosahatchee River estuary. Specifically, they were testing to find out what determined the movement of the young bull sharks.<ref name="ortega361">{{cite journal|last=Ortega|first=Lori A.|coauthors=Heupel, Michelle R.; van Beynen, Philip and Motta, Philip J. |title=Movement patterns and water quality preferences of juvenile bull sharks (''Carcharhinus lecuas'') in a Florida estuary|journal=Evionrmen Biol Fish|year=2009|volume=84|pages=361–373|doi=10.1007/s10641-009-9442-2|issue=4}}</ref>  It was found that the young bull sharks synchronously moved downriver when the environmental conditions changed.<ref name="ortega361"/>  This large movement of young bull sharks were found to be moving as a response rather than other external factors such as predators. An interesting find was that the movement was directly related to the bull shark conserving energy for itself. One way the bull shark is able to conserve energy is that when the tidal flow changes, the bull shark uses the tidal flow in order to conserve energy as it moves downriver.<ref name="ortega361"/>  Another way for the bull shark to conserve energy is to decrease the amount of energy needed to osmoregulate the surrounding environment.<ref name="ortega361"/>
 ==Ecology==
-Bull sharks are [[apex predator]]s and rarely have to fear being attacked by other animals. Humans are their biggest threat. Larger sharks, such as the [[tiger shark]] and [[great white shark]], may attack them.<ref name="FLMNH" /> There have been stories documented in the media of [[saltwater crocodile]]s preying on young bull sharks in the rivers and estuaries of [[Northern Australia]].<ref name='Croc Eat Shark'>{{cite web|url=http://www.underwatertimes.com/news.php?article_id=84173256109 |title=No Bull: Saltwater Crocodile Eats Shark |accessdate=2008-06-15 |date=2007-08-13 |work=UnderwaterTimes.com }}</ref>
+Bull sharks are [[apex predator]]s and rarely have to fear being attacked by other animals. Humans are their biggest threat. Larger sharks, such as the [[tiger shark]] and [[great white shark]], may attack them.<ref name="FLMNH" /> There have been stories documented in the media of [[saltwater crocodile]]s preying on young bull sharks in the rivers and estuaries of [[Northern Australia]].<ref name='Croc Eat Shark'>{{cite web|url=http://www.underwatertimes.com/news.php?article_id=84173256109 |title=No Bull: Saltwater Crocodile Eats Shark |accessdate=15 June 2008 |date=13 August 2007 |work=UnderwaterTimes.com }}</ref>
 ==See also==
@@ Line 134: / Line 135: @@
 * {{FishBase_species|genus=Carcharhinus|species=leucas|year=2005|month=09}}
 * {{marinebio|id=83|name=Bull shark, Carcharhinus leucas}}
-* Sunday Herald Sun, Sunday, April 23, 2005</div>
+* Sunday Herald Sun, Sunday, 23 April 2005</div>
 ==External links==

v t e Extant requiem shark species
Kingdom Animalia Phylum Chordata Class Chondrichthyes Subclass Elasmobranchii Subdivision Selachii Order Carcharhiniformes
Carcharhinus	Blacknose shark (C. acronotus) Silvertip shark (C. albimarginatus) Bignose shark (C. altimus) Graceful shark (C. amblyrhynchoides) Grey reef shark (C. amblyrhynchos) Pigeye shark (C. amboinensis) Borneo shark (C. borneensis) Copper shark (C. brachyurus) Spinner shark (C. brevipinna) Nervous shark (C. cautus) Pacific smalltail shark (C. cerdale) C. coatesi Whitecheek shark (C. dussumieri) Silky shark (C. falciformis) Creek whaler (C. fitzroyensis) Galapagos shark (C. galapagenisis) Pondicherry shark (C. hemiodon) Finetooth shark (C. isodon) Smoothtooth blacktip shark (C. leiodon) Bull shark (C. leucas) Blacktip shark (C. limbatus) Oceanic whitetip shark (C. longimanus) Hardnose shark (C. macloti) Blacktip reef shark (C. melanopterus) Dusky shark (C. obscurus) Caribbean reef shark (C. perezi) Sandbar shark (C. plumbeus) Smalltail shark (C. porosus) Blackspot shark (C. sealei) Night shark (C. signatus) Spot-tail shark (C. sorrah) Australian blacktip shark (C. tilstoni) C. tjutjot
Galeocerdo	Tiger shark (G. cuvier)
Glyphis	Borneo river shark (G. fowlerae) Ganges shark (G. gangeticus) Northern river shark (G. garricki) Speartooth shark (G. glyphis) Irrawaddy river shark (G. siamensis)
Isogomphodon	Daggernose shark (I. oxyrhynchus)
Lamiopsis	Broadfin shark (L. temminckii) Borneo broadfin shark (L. tephrodes)
Loxodon	Sliteye shark (L. macrorhinus)
Nasolamia	Whitenose shark (N. velox)
Negaprion	Sicklefin lemon shark (N. acutidens) Lemon shark (N. brevirostris)
Prionace	Blue shark (P. glauca)
Rhizoprionodon	Milk shark (R. acutus) Brazilian sharpnose shark (R. lalandii) Pacific sharpnose shark (R. longurio) Grey sharpnose shark (R. oligolinx) Caribbean sharpnose shark (R. porosus) Australian sharpnose shark (R. taylori) Atlantic sharpnose shark (R. terraenovae)
Scoliodon	Spadenose shark (S. laticaudus) Pacific spadenose shark (S. macrorhynchos)
Triaenodon	Whitetip reef shark (T. obesus)