Whale: Difference between revisions

Browse history interactively

← Previous edit Next edit →

Content deleted Content added

VisualWikitext

Inline

Revision as of 17:22, 5 March 2008

iphuck

@@ Line 1: / Line 1: @@
+iphuck
-{{otheruses1|the animal}}
-[[Image:Humpback stellwagen edit.jpg|thumb|right|A [[Humpback Whale]].]]
-'''Whales''' are [[cetacea]]ns which are neither [[dolphin]]s (i.e. members of the families [[Oceanic dolphin|Delphinidae]] or [[River dolphin|Platanistoidae]]) nor [[porpoise]]s.
-[[Orca]]s (Killer Whales) and [[Pilot whale]]s have "whale" in their name, but they are dolphins for the purpose of [[Taxonomy|classification]].
-The term '''''whale''''' is also sometimes used to refer to all [[cetacea]]ns or just larger ''cetaceans''.
-==Origins and taxonomy==
-[[Image:Fin whale from air.jpg|thumb|right|A [[Fin Whale]].]]
-{{seealso|Evolution of cetaceans|List of whale species}}
-All [[cetacea]]ns, including whales, dolphins and porpoises, are descendants of land-living [[mammal]]s of the [[Artiodactyl]] [[order (biology)|order]] (even-toed ungulate animals).  Both cetaceans and artiodactyl are now classified under the super-order [[Cetartiodactyla]] which includes both whales and [[hippopotamus|hippos]].  In fact, whales are the closest living relatives of hippos; they evolved from a [[Most recent common ancestor|common ancestor]] at around 54 million years ago.<ref name=science_news>{{cite web
- | url = http://www.sciencedaily.com/releases/2007/12/071220220241.htm
- | title = Whales Descended From Tiny Deer-like Ancestors
- | accessdate = 2007-12-21
- | author = Northeastern Ohio Universities Colleges of Medicine and Pharmacy (2007, December 21)
- | publisher = ScienceDaily
- }}</ref><ref name="Ancestors_Tale">{{cite book
-| first = Richard
-| last = Dawkins
-| authorlink = Richard Dawkins
-| title = [[The Ancestor's Tale|The Ancestor's Tale, A Pilgrimage to the Dawn of Life]]
-| publisher = Houghton Mifflin Company
-| location = Boston
-| year = 2004
-| id = ISBN 0-618-00583-8 }}</ref> Whales entered the water roughly 50 million years ago.<ref>{{cite web|url=http://news.bbc.co.uk/1/hi/sci/tech/1974869.stm|title=How whales learned to swim|publisher=BBC News|date=2002-05-08|accessdate=2006-08-20}}</ref>
-Cetaceans are divided into two suborders:
-*The [[baleen whale]]s are characterized by [[baleen]], a sieve-like structure in the upper jaw made of [[keratin]], which they use to filter [[plankton]] from the water. They are the largest species of whale.
-*The [[toothed whale]]s have teeth and prey on fish, squid, or both. An outstanding ability of this group is to sense their surrounding environment through [[animal echolocation|echolocation]].
-A complete up-to-date taxonomical listing of all [[cetacea]]n species, including all whales, is maintained at the [[Cetacea]] article.
-==Anatomy==
-[[Image:Baleen Whale Physical Characteristics.svg|thumb|right|Physical characteristics of a baleen whale.]]
-Like all mammals, whales breathe air into [[lung]]s, are [[endotherm|warm-blooded]], feed their young [[milk]] from [[mammary gland]]s, and have some (although very little) [[hair]].
-The body is [[fusiform]], resembling the streamlined form of a [[fish]]. The forelimbs, also called flippers, are paddle-shaped. The end of the tail holds the fluke, or tail fins, which provide propulsion by vertical movement.  Although whales generally do not possess hind limbs, some whales (such as [[sperm whale]]s and [[baleen whale]]s) sometimes have rudimentary hind limbs; some even with feet and digits.  Most species of whale bear a fin on their backs known as a [[dorsal fin]].
-Beneath the [[skin]] lies a layer of [[fat]], the [[blubber]]. It serves as an [[energy]] reservoir and also as [[Thermal insulation|insulation]]. Whales have a four-chambered [[heart]]. The [[neck]] [[vertebrae]] are fused in most whales, which provides stability during [[swimming]] at the expense of flexibility. They have a pelvis bone, which is a [[vestigial structure]].
-Whales breathe through their [[blowhole (biology)|blowholes]], located on the top of the head so the animal can remain submerged. [[Baleen whale]]s have two; [[toothed whale]]s have one. The shapes of whales' spouts when exhaling after a dive, when seen from the right angle, differ between species. Whales have a unique respiratory system that lets them stay underwater for long periods of time without taking in [[oxygen]]. Some whales, such as the [[Sperm Whale]], can stay underwater for up to two hours holding a single breath. The [[Blue Whale]] is the largest known mammal that has ever lived, and the largest living animal, at up to 35 m (105ft) long and 150 tons.
-Whales generally live for 40-200 years, depending on their species, but it is rare to find one that lives over a century. Recently a fragment of a lance used by commercial whalers in the 19th century has been found in a bowhead whale caught off Alaska. The fragment showed the whale is between 115 and 130 years old. <ref>{{cite web|url= http://www.news.com.au/dailytelegraph/story/0,22049,21897911-5001028,00.html|title=Hunting lance from 1800s found in whale| accessdate=2007-06-14}}</ref> "No other finding has been this precise," said John Bockstoce, an adjunct curator of the New Bedford Whaling Museum.<ref>{{cite web|url=http://news.yahoo.com/s/ap/20070613/ap_on_sc/century_old_whale;_ylt=AjWhLCsM2A25jvGQb8nOuGTMWM0F|title=19th century weapon found in whale| accessdate=2007-06-14}}</ref>
-Whale flukes often can be used as identifying markings, as is the case for [[humpback whale]]s.  This is the method by which the publicized errant [[Humphrey the whale]] was identified in three separate sightings.
-===Anatomy of the ear===
-{{Seealso|Evolution of cetaceans}}
-While there are direct similarities between the [[ear]]s of whales and [[human]]s, whales’ ears have specific adaptations to their underwater environment.  In humans, the middle ear works as an impedance matcher between the outside air’s low-impedance and the cochlear fluid’s high-impedance.  In aquatic mammals such as whales, however, there is no great difference between the outer and inner environments.  Instead of sound passing through outer ear to middle ear, whales receive sound through their lower [[jaw]], where it passes through a low-impedance, fat-filled cavity.<ref>{{cite web| url=http://instruct1.cit.cornell.edu/courses/bionb424/students2004/kls36/neuroanatomy.htm|title=Anatomy of a Whale's Ears| accessdate=2006-09-14}}</ref><ref>{{cite web |title=How is that whale listening? |url=http://www.eurekalert.org/pub_releases/2008-02/iop-hit020108.php |accessdate=2008-02-04}}</ref>
-==Behavior==
-[[Image:DSC 7334.JPG|thumb|right|A [[Humpback Whale]] breaching.]]
-Whales are widely classed as [[predator]]s, but their food ranges from microscopic [[plankton]] to very large fish. Males are called bulls; females, cows. The young are called calves.
-As mammals, whales breathe air and must surface to get [[oxygen]].  This is done through a blowhole.  Many whales also exhibit other [[Whale surfacing behaviour|surfacing behaviours]] such as breaching and tail slapping.
-Because of their environment (and unlike many animals), whales are conscious breathers: they decide when to breathe. All mammals [[sleep]], including whales, but they cannot afford to fall into an unconscious state for too long, since they need to be conscious in order to breathe. It is thought that only one hemisphere of their brains sleeps at a time, so that whales are never completely asleep, but still get the rest they need.
-Whales also communicate with each other using lyrical sounds, called [[whale song]]. Being so large and powerful, these sounds are also extremely loud (depending on the species); sperm whales have only been heard making clicks, as all toothed whales ([[Odontoceti]]) use [[animal echolocation|echolocation]] and can be heard for many miles. They have been known to generate about 20,000 acoustic watts of sound at 163 decibels.<ref>{{cite web|url=http://www.makeitlouder.com/Decibel%20Level%20Chart.txt|title=Table of sound decibel levels|accessdate=2006-09-14}}</ref>
-Females give birth to a single calf. Nursing time is long (more than one year in many species), which is associated with a strong bond between mother and young. In most whales reproductive maturity occurs late, typically at seven to ten years. This [[K selection|mode of reproduction]] spawns few offspring, but provides each with a high probability of survival in the wild.
-The male genitals are retracted into cavities of the body during swimming, so as to be streamlined and reduce drag. Most whales do not maintain fixed partnerships during mating; in many species the females have several mates each season. At birth newborn are delivered tail-first, minimising the risk of drowning. Whale cows nurse by actively squirting milk the consistency of [[toothpaste]] into the mouths of their young preventing loss to the surrounding aquatic environment.<ref>{{cite episode
-| series=[[Modern Marvels]] | title=Milk | url=http://www.history.com/minisites/modernmarvels | season=14 | network=[[The History Channel]] | airdate=2008-01-07}}</ref>
-==Human effects==
-===Whaling===
-{{Main|Whaling}}
-[[Image:Petrified whale bone.JPG|A [[fossil]] whale bone found at [[California]] [[Beach]]|thumb|150px|left]]
-[[Image:Members of the International Whaling Commission.PNG|thumb|right|World map of International Whaling Commission (IWC) members/non-members(member countries in blue).]]
-[[Image:Blue Whale population, Pengo.svg|thumb|right|World population graph of [[Blue Whale]]s (Balaenoptera musculus).]]
-[[Image:18th century arctic whaling.jpg|thumb|right|Eighteenth century engraving of Dutch whalers hunting [[Bowhead Whale]]s in
-the [[Arctic]]. [[Beerenberg]] on [[Jan Mayen Land]] can be seen in the background.]]
-Some species of large whales are endangered as a result of large-scale [[whaling]] during the nineteenth and twentieth centuries. For centuries large whales have been hunted for oil, meat, baleen and [[ambergris]] (a perfume ingredient from the intestine of [[sperm whale]]s). By the middle of the 20th century, whaling left many populations severely depleted.
-The [[International Whaling Commission]] introduced a six year moratorium on all commercial whaling in 1986, which has been extended to the present day. For various reasons some exceptions to this moratorium exist; current whaling nations are [[Norway]], [[Iceland]] and [[Japan]] and the aboriginal communities of [[Siberia]], [[Alaska]] and northern [[Canada]]. For details, see [[whaling]].
-Several species of small whales are caught as [[bycatch]] in fisheries for other species. In the [[tuna]] fishery in the Eastern Tropical Pacific thousands of dolphins were drowned in purse-seine nets, until measures to prevent this were introduced. Fishing gear and deployment modifications, and [[eco-labelling]] (''dolphin-safe'' or ''dolphin-friendly'' brands of canned tuna), have contributed to a reduction in the mortality of dolphins by tuna fishing vessels in recent years. In many countries, small whales are still hunted for food, oil, meat or bait.
-===[[Sonar]] interference===
-Environmentalists have long argued that some cetaceans, including whales, are endangered by [[sonar]] used by advanced navies. In 2003 British and Spanish scientists suggested in ''[[Nature (journal)|Nature]]'' that sonar is connected to whale beachings and to signs that the beached whales have experienced decompression sickness. <ref>{{cite web| url=http://news.bbc.co.uk/2/hi/science/nature/3173942.stm|title=Sonar may cause Whale deaths|publisher=BBC News|date=2003-10-08|accessdate=2006-09-14}}</ref> Mass [[beached whale|whale beaching]]s occur in many species, mostly beaked whales that use echolocation systems for deep diving. The frequency and size of beachings around the world, recorded over the last 1,000 years in religious tracts and more recently in scientific surveys, has been used to estimate the changing population size of various whale species by assuming that the proportion of the total whale population beaching in any one year is constant.
-Despite the concerns raised about sonar which may invalidate this assumption, this population estimate technique is still popular today. Researchers in the area ([http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&db=pubmed&term=talpalar%20AND%20grossman. Talpalar & Grossman, 2005]) support the view that it is the combination of the high pressure environment of deep-diving with the disturbing effect of the sonar which causes [[decompression sickness]] and stranding of whales. Thus, an exaggerated startle response occurring during deep diving may alter orientation cues and produce rapid ascent.
-Following public concern, the U.S. Defense department has been ordered by the U.S. judiciary to strictly limit use of its [[Low Frequency Active Sonar]] during peacetime. Attempts by the UK-based [[Whale and Dolphin Conservation Society]] to obtain a [[public inquiry]] into the possible dangers of the [[Royal Navy]]'s equivalent (the "[[Sonar 2087|2087]]" sonar launched in December 2004) have so far failed. The [[European Parliament]] on the other hand has requested that EU members refrain from using the powerful sonar system until an environmental impact study has been carried out.
-===Other environmental disturbances===
-Conservationists are concerned that seismic testing used for oil and gas exploration may also damage the hearing and echolocation capabilities of whales. They also suggest that disturbances in magnetic fields caused by the testing may also be responsible for beaching. <ref>{{cite web| url=http://www.sustainability.ca/Docs/Impact%20of%20Seismic%20Surveys%20on%20Whales.pdf?CFID=9951883&CFTOKEN=72165442| title=Seismic testing and the impacts of high intensity sound on whales| accessdate=2006-09-14}}</ref>
-Some scientists and environmentalists suggest that some whale species are also endangered due to a number of other human activities such as the unregulated use of fishing gear, that often catch anything that swims into them, collisions with ships.  Toxins and the combination of toxins, particularly [[Persistent Organic Pollutant|POPs]] (which concentrate up the food chain), are known to cause hearing loss.<ref>{cite web |url=http://www.yale.edu/opa/newsr/06-04-13-02.all.html |title=Yale Researchers Find Environmental Toxins Disruptive to Hearing in Mammals |date=2006-04-13}}</ref>
-Whales are also threatened by [[climate change]] and [[global warming]]. As the [[Antarctic Ocean]] warms, [[krill]] populations, that are the main food source of some species of whales, reduce dramatically, being replaced by jelly like [[salp]]s.{{Fact|date=April 2007}}
-==Whales in culture==
-[[Image:Nantucket historical assocation whaling museum weather vane.jpg|right|thumb|Whale weather-vane atop the Nantucket Historical Association Whaling Museum.]]
-*A [[kenning]] in ''[[Beowulf]]'' refers to the [[sea]] as the "whale-road".
-*[[Procopius]] mentions a whale, nicknamed ''Porphyrio'' by the [[Byzantine Empire|Byzantines]], who depleted fisheries in the [[Sea of Marmara]].
-*The [[King James Version of the Bible]] mentions whales four times: "And God created great whales" ([[Genesis]] 1:21); "Am I a sea, or a whale, that thou settest a watch over me? ([[Book of Job|Job]] 7:12); "Thou art like a young lion of the nations, and thou art as a whale in the seas ([[Ezekiel]] 32:2); and "For as Jonas [sic] was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth" ([[Gospel of Matthew|Matthew]] 12:40).
-**The [[New International Version]] uses "creatures of the sea"; "monster of the deep"; "monster"; and "huge fish" respectively instead of the word 'whale'.
-**The story of [[Jonah]] being swallowed by a whale also is mentioned in the [[Qur'an]].
-**[[John Tavener]]'s composition ''[[The Whale]]'' is based on the story of Jonah.
-*[[Alan Hovhaness]] wrote a piece for orchestra entitled ''And God Created Great Whales''.
-*The poet [[Heathcote Williams]] wrote a long poem entitled ''Whale Nation''.
-*In the children's novel ''[[The Adventures of Pinocchio]]'' and subsequent adaptations, [[Pinocchio]] and his master are swallowed by a whale.
-*A [[whaling]] voyage is the plot of [[Herman Melville]]'s [[novel]] ''[[Moby-Dick]].'' In the book, Melville classed whales as "a spouting [[fish]] with a horizontal [[tail]]", this despite [[science]] suggesting otherwise the [[18th century|previous century]]. (His [[Ishmael (Moby-Dick)|narrator]] acknowledged "the grounds upon which [[Carolus Linnaeus|Linnaeus]] would fain have banished the whales from the waters" but writes that when he presented them to "my friends Simeon Macey and Charley Coffin, of [[Nantucket]] ... they united in the opinion that the reasons set forth were altogether insufficient. Charley profanely hinted they were [[humbug]]" (Chapter 32).) Melville's book is a classic of [[American literature]]: part [[adventure novel]], part [[metaphysics|metaphysical]] [[allegory]], and part [[natural history]]; it is essentially a summary of 19th century knowledge about the [[biology]], [[ecology]] and cultural significance of the whale.
-*Some cultures associate some level of [[divinity]] with the whale, such as in some places in [[Ghana]] and the [[Vietnamese people|Vietnamese]], who occasionally hold funerals for beached whales, a throwback to Vietnam's ancient sea-based [[Austro-asiatic]] culture.
-*Festivals celebrating whales have sprung in both [[Sitka]] and [[Kodiak, Alaska|Kodiak]] [[Alaska]]. They feature speakers on [[marine biology]] and celebrate the creatures with art, music, [[whale watching]] cruises, and symposia.
-*In the British series ''[[Hitchhiker's Guide to the Galaxy]]'' a whale, alongside a bowl of petunias, is created by the use of the Infinite Improbability Drive.
-==See also==
-{{cetaceaportal}}
-* [[Cetacea]]
-* [[List of whale species]]
-* [[:Category:Cetaceans]]
-==References==
-{{Reflist|2}}
-;General references
-<div class="references-small">
-* {{cite book |last=Carwardine |first=M.| date=2000 |title=Whales, Dolphins and Porpoises| publisher=Dorling Kindersley| id= ISBN 0-7513-2781-6}}
-</div>
-==External links==
-* [http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html Whale Evolution]
-* [http://oceans.greenpeace.org/en/our-oceans/whaling Greenpeace work defending whales]
-* [http://savethewhales.org/stwsong_hi.html  Save the Whales, founded in 1977]
-* [http://aquaticmammals.org AquaNetwork Marine Mammal Project]
-* [http://news.bbc.co.uk/1/hi/sci/tech/239966.stm Oldest whale fossil confirms amphibious origins]
-* [http://www.sciencedaily.com/news/plants_animals/dolphins_and_whales/ Research on dolphins and whales from Science Daily]
-* [http://www.wdcs.org/ Whale and Dolphin Conservation Society - latest news and information on whales and dolphins]
-* [http://www.oceania.org.au/ The Oceania Project - Caring for whales and dolphins]
-[[Category:Cetaceans]]
-[[ar:حوت]]
-[[zh-min-nan:Hái-ang]]
-[[bg:Кит (биология)]]
-[[ca:Balena]]
-[[cs:Velryba]]
-[[cy:Morfil]]
-[[da:Hvaler]]
-[[de:Wale]]
-[[es:Ballena]]
-[[eo:Baleno]]
-[[fa:نهنگ]]
-[[fr:Baleine]]
-[[io:Baleno]]
-[[id:Paus (mamalia)]]
-[[is:Hvalur]]
-[[it:Balena]]
-[[ln:Mondɛ́lɛ́ (nyama)]]
-[[mk:Кит]]
-[[ml:തിമിംഗലം]]
-[[ms:Ikan paus]]
-[[nl:Walvissen]]
-[[ja:クジラ]]
-[[no:Hval]]
-[[nrm:Baleine]]
-[[oc:Balena]]
-[[ug:كىت]]
-[[pl:Wieloryb]]
-[[pt:Baleia]]
-[[ro:Balenă]]
-[[ru:Кит]]
-[[fi:Valas]]
-[[sv:Valar]]
-[[yi:וואל-פיש]]
-[[uk:Китоподібні]]
-[[zh-yue:鯨魚]]
-[[zh:鯨]]