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| publisher = Jeheskel Shoshani, William J. Kupsky b, Gary H. Marchant
| publisher = Jeheskel Shoshani, William J. Kupsky b, Gary H. Marchant
| url = http://www.elephantvoices.org/tools/documents/ElephantBrain_shoshani.pdf
| url = http://www.elephantvoices.org/tools/documents/ElephantBrain_shoshani.pdf
| accessdate = 2007-11-09|format=PDF}}</ref> However, the cortex of the elephant brain is "thicker than that of cetaceans", and is believed to have as many cortical [[neurons]] (nerve cells) and cortical [[synapse]]s as that of humans which exceeds that of [[cetaceans]].<ref name="Roth"/>{{rp|71}} Elephants are believed to rank equal with dolphins in terms of problem solving abilities and many scientists tend to rank elephant [[intelligence]] at the same level as [[cetacean]]s<ref>{{cite news
| accessdate = 2007-11-09|format=PDF}}</ref> However, the cortex of the elephant brain is "thicker than that of cetaceans", and is believed to have as many cortical [[neurons]] (nerve cells) and cortical [[synapse]]s as that of humans which exceeds that of [[cetaceans]].<ref name="Roth"/>{{rp|71}} Elephants are believed to rank equal with dolphins in terms of problem solving abilities and many scientists tend to rank elephant [[intelligence]] at the same level as cetaceans<ref>{{cite news
| title = Elephants At Work
| title = Elephants At Work
| url = http://www.chiangmai-chiangrai.com/elephants_at_work.html
| url = http://www.chiangmai-chiangrai.com/elephants_at_work.html

Revision as of 01:47, 19 December 2010

File:Ele-brain.png
Human, pilot whale and elephant brains up to scale. (1)-cerebrum (1a)-temporal lobe and (2)-cerebellum

Elephants are amongst the world's most intelligent species. With a mass just over 5 kg (11 lb), elephant brains are larger than those of any other land animal, and although the largest whales have body masses twentyfold those of a typical elephant, whale brains are barely twice the mass of an elephant's brain. The elephant’s brain is similar to that of humans in terms of structure and complexity - such as the elephant’s cortex having as many neurons as a human brain[1], suggesting convergent evolution.[2] A wide variety of behaviors, including those associated with grief, learning, allomothering, mimicry, art, play, a sense of humor, altruism, use of tools, compassion, self-awareness, memory and possibly language[3] all point to a highly intelligent species that are thought to be equal with cetaceans[4][5] and primates[6][7]. Due to the high intelligence and strong family ties of elephants, some researchers argue it is morally wrong for humans to cull them.[8]

Aristotle once said that elephants were "The beast which passeth all others in wit and mind"[9].

Brain structure

Cerebral cortex

The elephant (both Asian and African) has a very large and highly convoluted neocortex, a trait also shared by humans, apes and certain dolphin species. Scientists see this as a sign of complex intelligence. While this is the widely held belief, there is at least one exception: the echidna has a highly developed brain, yet is not considered to be highly intelligent[10]. Asian elephants have the greatest volume of cerebral cortex available for cognitive processing of all existing land animals. Elephants have a volume of cerebral cortex available for cognitive processing that exceeds that of any primate species, and extensive studies place elephants in the category of great apes in terms of cognitive abilities for tool use and tool making[6]. The elephant brain exhibits a gyral pattern more complex and with more numerous convolutes/brain folds than that of humans, primates and carnivores, but less complex than cetaceans.[11] However, the cortex of the elephant brain is "thicker than that of cetaceans", and is believed to have as many cortical neurons (nerve cells) and cortical synapses as that of humans which exceeds that of cetaceans.[1]: 71  Elephants are believed to rank equal with dolphins in terms of problem solving abilities and many scientists tend to rank elephant intelligence at the same level as cetaceans[12].

Other features of the brain

Elephants also have a very large and highly convoluted hippocampus, a brain structure in the limbic system that is much bigger than that of any human, primate or cetacean[13]. The hippocampus of an elephant takes up about 0.7% of the central structures of the brain, comparable to 0.5% for humans and with 0.1% in Risso’s dolphins and 0.05% in bottlenose dolphins[14]. The hippocampus is linked to emotion through the processing of certain types of memory, especially spacial. This is thought to possibly be why elephants suffer from psychological flashbacks and the equivalent of post-traumatic stress disorder (PTSD) [15][16]. The encephalization quotient (EQ) of elephants "ranges from 1.13 to 2.36. The total EQ average is 1.88, with an average of 2.14 for Asian elephants, and 1.67 for African" [17]: 151 . There is considerable debate about whether the EQ, or size of the brain relative to body size, is an accurate gauge for intelligence, especially since the animal with the highest EQ is a treeshrew[18], yet they are not considered to be highly intelligent.

Brain size at birth relative to adult brain size

Like humans, elephants must learn behavior as they grow up. They are not born with the instincts of how to survive.[19] Elephants have a very long period in their lives for learning, lasting for around ten years. One comparative way to try to gauge intelligence is to compare brain size at birth to the fully developed adult brain. This indicates how much learning a species accumulates while young. The majority of mammals are born with a brain close to 90% of the adult weight.[19] Humans are born with 28%[19] of the adult weight, bottlenose dolphins with 42.5%,[20] chimpanzees with 54%,[19] and elephants with 35%.[21]. This indicates that elephants have the highest amount of learning to undergo next to humans and behavior is not mere instinct but must be taught throughout life. It should be noted that instinct is quite different from learned intelligence. Parents will teach their young how to feed, use tools and learn their place in highly complex elephant society. The cerebrum temporal lobes, which functions as storage of memory are much larger than that of a human[19].

Spindle neurons

Spindle cells appear to play a central role in the development of intelligent behavior. Initially, it was thought that the presence of spindle neurons was unique to humans and the great apes. However, studies have shown that spindle neurons are also found in the brains of both Asian and African elephants,[22]: 242  as well as humpback whales, fin whales, killer whales, sperm whales[23][24], bottlenose dolphins, Risso’s dolphins, and beluga whales.[25] The remarkable similarity between the elephant brain and the human brain supports the thesis of convergent evolution.[26]: 154 

Elephant society

The elephant has one of the most closely knit societies of any living species. Elephant families can only be separated by death or capture. Cynthia Moss, an ethologist specialising in elephants, recalls an event involving a family of African elephants. Two members of the family were shot by poachers, who were subsequently chased off by the remaining elephants. Although one of the elephants died, the other, named Tina, remained standing but with knees beginning to give way. Two family members, Trista and Teresia (Tina’s mother) walked to both sides of Tina and leaned in to hold her up. Eventually, Tina grew so weak she fell to the ground and died. However, Trista and Teresia did not give up but continually tried to lift her. They managed to get Tina into a sitting position, but her body was lifeless and fell to the ground again. As the other elephant family members became more intensely involved in the aid, they tried to put grass into Tina’s mouth. Teresia then put her tusks beneath Tina’s head and front quarters and proceeded to lift her. As she did so, her right tusk broke completely off, right up to the lip and nerve cavity. The elephants gave up trying to lift Tina but didn’t leave her; instead, they began to bury her in a shallow grave and throw leaves over her body. They stood over Tina for the night, and then began to leave in the morning. The last to leave was Teresia[27].

Because elephants are so closely knit and highly matriarchal, a family can be devastated by the death of another (especially a matriarch) and some groups never recover their organization. Cynthia Moss has observed a mother, after the death of her calf, walk sluggishly at the back of a family for many days[27].

Edward Topsell stated in his publication, The History of Four-Footed Beasts in 1658 that "There is no creature among all the Beasts of the world which hath so great and ample demonstration of the power and wisdom of almighty God as the elephant[28]."

Elephant altruism

Elephants are thought to be highly altruistic animals that will even aid other species, including humans, in distress. In India, an elephant was helping locals lift logs by following a truck and placing the logs in pre-dug holes upon instruction from the mahout (elephant trainer). At a certain hole, the elephant refused to lower the log. The mahout came to investigate the hold up and noticed a dog sleeping in the hole. The elephant only lowered the log when the dog was gone.[29]

Cynthia Moss has often seen elephants going out of their way to avoid hurting or killing a human, even when it was difficult for them (such as having to walk backwards to avoid a person).

Joyce Poole documented an encounter told to her by Colin Francombe on Kuki Gallman's Laikipia Ranch. A ranch herder was out on his own with camels when he came across a family of elephants. The matriarch charged at him and knocked him over with her trunk, breaking one of his legs. In the evening, when he didn't return, a search party was sent in a truck to find him. When the party discovered him, he was being guarded by an elephant. The animal charged the truck, so they shot over her and scared her away. The herdsman later told them that when he couldn't stand up, the elephant used her trunk to lift him under the shade of a tree. She guarded him for the day and would gently touch him with her trunk.[19]

Self medication

Further information: Zoopharmacognosy

Elephants in Africa will self-medicate by chewing on the leaves of a tree from the Boraginaceae family, which induces labor. Kenyans also use this tree for the same purpose[30].

Death ritual

Elephants are the only other species on Earth other than Homo sapiens sapiens and Neanderthals[31] known to have any recognizable ritual around death. They show a keen interest in the bones of their own kind (even unrelated elephants that have died long ago). They are often seen gently investigating the bones with their trunks and feet, and remaining very quiet. Sometimes elephants that are completely unrelated to the deceased will still visit their graves.[9] When an elephant is hurt, other elephants (also even if they are unrelated) will aid them.[19]

Elephant researcher Martin Meredith recalls an occurrence in her book about a typical elephant death ritual that was witnessed by Anthony Martin-Hall, a South African biologist who had studied elephants in Addo, South Africa for over 8 years. The entire family of a dead matriarch, including her young calf were all gently touching her body with their trunks and tried to lift her. The elephant herd were all rumbling loudly. The calf was observed to be weeping and made sounds that sounded like a scream but then the entire herd fell incredibly silent. They then began to throw leaves and dirt over the body and broke off tree branches to cover her. They spent the next 2 days quietly standing over her body. They sometimes had to leave to get water or food, but they would always return.[32] Occurrences of elephants behaving this way around human beings are common through Africa. On many occasions, they have buried dead or sleeping humans or aided them when they were hurt.[19] Meredith also recalls an event told to her by George Adamson, a Kenyan Game Warden regarding an old Turkana woman who fell asleep under a tree after losing her way home. When she woke up, there was an elephant standing over her, gently touching her. She kept very still because she was very frightened. As other elephants arrived, they began to scream loudly and buried her under branches. She was found the next morning by the local herdsmen, unharmed.[32]

George Adamson also recalls when he shot a Bull elephant from a herd that kept breaking into the Government gardens of Northern Kenya. George gave the elephant’s meat to local Turkana Tribesmen and then dragged the rest of the carcass half a mile away. That night, the other elephants found the body and took the shoulder blade and leg bone and returned the bones to the exact spot the elephant was killed.[33] Scientists often argue the extent that elephants feel emotion. A large variety of animals display what appears to be ‘sorrow’ through body language, posture, movement and actions but seeing elephants standing over a body, burying them, refusing to leave and their trunks being observed hanging limp certainly seems evidence that perhaps much deeper and complex emotions are involved.[33]

Play

Joyce Poole on many occasions has observed wild African elephants at play. They apparently do things for their own and others' entertainment. Elephants have been seen sucking up water, holding their trunk high in the air, and then spraying the water like a fountain[19].

Mimicry

Recent studies have shown that elephants can also mimic sounds they hear. The discovery was found when Mlaika, an orphaned elephant, would copy the sound of trucks passing by. So far, the only other animals that are thought to mimic sounds are whales, dolphins, bats, primates and birds[34]. Calimero, an African elephant who was 23 years old also exhibited a unique form of mimicry. He was in a Swiss zoo with some Asian elephants. Asian elephants use chirps that are different from African elephants' deep rumbling noises. Calimero also began to chirp and not make the deep calls like his species normally would [35]. Kosik, an Indian elephant at Everland Amusement Park, South Korea surprised trainers when they thought there was a person in his enclosure but it was actually Kosik imitating Jong Gap Kim, his trainer. Kosik can make sounds imitating up to eight Korean words, including "sit", "no", "yes" and "lie down". His mimicry is remarkably human-sounding. Kosik produces humanlike sounds by putting his trunk in his mouth and then shaking it while breathing out, similar to how people whistle with their fingers[36]. Elephants use contact calls to stay in touch with one another when they are out of one another’s sight. Female elephants are able to remember and distinguish the contact calls of female family and bond group members from those of females outside of their extended family network. They can also distinguish between the calls of family units depending upon how frequently they came across them[37].

Tool use

Further information: Tool use by animals

Elephants show a remarkable ability to use tools, using their trunk like an arm. Elephants have been observed digging holes to drink water and then ripping bark from a tree, chewing it into the shape of a ball, filling in the hole and covering over it with sand to avoid evaporation. The elephant later went back to this spot for a drink. They also often use branches to swat flies or scratch themselves[29]. Elephants have also been known to drop very large rocks onto an electric fence to either ruin the fence or cut off the electricity[19].

Art

File:Elephant painting thailand.JPG
A painting elephant

Like several other species, elephants are able to produce abstract art using their trunks to hold brushes. An example of this was shown in the TV program Extraordinary Animals, where elephants at a camp in Thailand were able to draw a ' self portrait' with a flower. Although the images are drawn by the elephants, there is always a human person assisting and guiding the movement.[citation needed] From those presentations it cannot be definitely evaluated, whether the elephants are conscious about the shape of their drawings or not.[dubious – discuss]

This extraordinary video documentation of an elephant painting a picture of an elephant - possibly indicating self-awareness - has become widespread on internet news and video websites.[38] The quality of the painting is extremely high, leading many astonished viewers to doubt the video's authenticity. The website snopes.com, which specializes in debunking urban legends, lists the video as "true", in that the elephant produced the brush strokes, but notes that the similarity of the produced paintings is indicative of a learned sequence of strokes rather than a creative effort on the part of the elephant.[39]

Problem solving ability

Elephants are able to spend a lot of time working on problems. They are able to radically change their behavior to face a new challenge, a hallmark of complex intelligence. In the 1970s at Marine World Africa, USA, there lived an Asian elephant named Bandula. Bandula worked out how to break open or unlock several of the pieces of equipment used to keep the shackles on her feet secure. The most complex device was a 'brommel hook', a device that will close when two opposite points are slid together. Bandula used to fiddle with the hook until it slid apart when it was aligned. Once she had freed herself, she would help the other elephants escape also[30]. In Bandula’s case and certainly with other captive elephants, there was an element of 'deception' involved during escapes, such as the animals looking around making sure no one was watching[30].

In another case, a female elephant worked out how she could unscrew iron rods with an eye hole that were an inch thick. She used her trunk to create leverage and then untwist the bolt[30].

Ruby, an Asian elephant at Phoenix Zoo would often ‘eavesdrop’ onto conversations keepers would have talking about her. When she heard the word "paint", she became very excitable. The colours she favoured were green, yellow, blue and red. On one particular day, there was a fire truck that came and parked outside her enclosure where a man had just had a heart attack. The lights on the truck were flashing red, white and yellow. When Ruby painted later on in the day, she chose those colours. She also showed a preference for particular colours that the keepers wore[30].

Harry Peachey, an elephant trainer, developed a cooperative relationship with an elephant named Koko. Koko would help out the keepers, "prompting" the keepers to encourage him with various commands and words that Koko would learn. Peachey stated that elephants are almost 'predisposed' to cooperate and work with humans as long as they are treated with respect and sensitivity. Koko worked out when his keepers needed a bit of ‘elephant help’ when they were transferring the females of the group to another zoo. When the keepers wanted to transfer a female, usually they would say her name, followed by the word 'transfer' (e.g. "Connie transfer"). Koko soon figured out what this meant. If the keepers asked an elephant to transfer and they didn’t budge, they would say "Koko, give me a hand". When he heard this, Koko would help. Peachey firmly believes that after 27 years of working with elephants, they can understand semantics/syntax of some of the words they hear. This is something thought to be very rare in the animal kingdom[30].

A study by Dr. Naoko Irie of Tokyo University has shown that elephants demonstrate skills at arithmetic. The experiment "consist[ed] of dropping varying numbers of apples into two buckets in front of the [Ueno Zoo] elephants and then recording how often they could correctly choose the bucket holding the most fruit". When more than one apple was being dropped into the bucket, this meant that the elephants had to "keep running totals in their heads to keep track of the count". The results showed that "Seventy-four percent of the time, the animals correctly picked the fullest bucket. An African elephant named Ashya scored the highest with an amazing eighty-seven percent…. Humans in this same contest managed a success rate of just sixty-seven percent". The study was also filmed to ensure its accuracy[40].

Self awareness

Asian Elephants have joined a small group of animals, including great apes, bottlenose dolphins and magpies, that exhibit self awareness. The study was conducted with the Wildlife Conservation Society (WCS) using elephants at the Bronx Zoo in New York. Although many animals will respond to a mirror, very few show any evidence that they recognize it is in fact themselves in the mirror reflection.

The Asian elephants in the study also displayed this type of behavior when standing in front of a 2.5m-by-2.5m mirror - they inspected the rear and brought food close to the mirror for consumption.

Evidence of elephant self awareness was shown when the elephant Happy repeatedly touched a painted "X" on her head with her trunk, a mark which could only be seen in the mirror. Happy ignored another mark made with colourless paint that was also on her forehead to ensure she was not merely reacting to a smell or feeling.

Frans De Waal, who ran the study stated, "These parallels between humans and elephants suggest a convergent cognitive evolution possibly related to complex society and cooperation."[41]

Joyce Poole, of the Amboseli Elephant Research Project, Kenya, has demonstrated vocal learning and imitation in elephant of sounds made by each other and in the environment. She is beginning to research whether sounds made by elephants have dialects, a trait that is rare in the animal kingdom.[34]

Self awareness and culling

There has been considerable debate over the issue of culling African elephants in South Africa’s Kruger National Park as a means of controlling the population. Some scientists and environmentalists argue that it is "unnecessary and inhumane" to cull them[42] since "elephants resemble humans in a number of ways, not least by having massive brains, social bonds that appear to be empathetic, long gestations, high intelligence, offspring that require an extended period of dependent care, and long life spans".[43]: 20824  A South African Animal Rights group "asked in a statement anticipating the announcement, 'How much like us do elephants have to be before killing them becomes murder?'".[44] Others argue that culling is necessary when biodiversity is threatened.[45]

See also

References

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  24. ^ Hof, P. R., Van der Gucht, E. (2007). "Structure of the cerebral cortex of the humpback whale, Megaptera novaeangliae (Cetacea, Mysticeti, Balaenopteridae)". Anat Rec (Hoboken). 290 (1): 1–31. doi:10.1002/ar.20407. PMID 17441195. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
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  27. ^ a b Moss, Cynthia (2001). Elephant Memories: Thirteen Years in the Life of an Elephant Family. Chicago, Illinois: University of Chicago Press. ISBN 0226542378.
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  32. ^ a b Meredith, Martin (2004). Elephant Destiny: Biography of an Endangered Species in Africa. Canada: PublicAffairs. pp. 184–186. ISBN 1586482335.
  33. ^ a b Page, George (1999). The Singing Gorilla: Understanding Animal Intelligence. London, United Kingdom: Headline Book Publishing. pp. 175–177. ISBN 0747275696.
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  37. ^ "Size of the Elephant Brain". All Experts. Retrieved 2007-10-31.
  38. ^ "Elephant Painting". youtube.com. Retrieved 2008-04-03.
  39. ^ "Elephant Painting Rumor". snopes.com. Retrieved 2008-04-03.
  40. ^ Dubroff, M Dee (August 25, 2010). "Are Elephants Smarter than Humans When It Comes to Mental Arithmetic?". Digital Journal. Retrieved 2010-08-29.
  41. ^ "Elephants' Jumbo Mirror Ability". BBC News. 2006-10-31. Retrieved 2007-10-31.
  42. ^ Wine, Michael (2007-03-01). "Cautious call for elephant cull". The New York Times. Retrieved 2010-08-29.
  43. ^ Goodman, M.; Sterner, K.; Islam, M.; Uddin, M.; Sherwood, C.; Hof, P.; Hou, Z.; Lipovich, L.; Jia, H. (19 November). "Phylogenomic analyses reveal convergent patterns of adaptive evolution in elephant and human ancestries". Proceedings of the National Academy of Sciences. 106 (49): 20824–20829. doi:10.1073/pnas.0911239106. PMC 2791620. PMID 19926857. {{cite journal}}: Check date values in: |date= and |year= / |date= mismatch (help)
  44. ^ "S Africa to allow elephant cull". BBC News. 2008-02-25. Retrieved 2010-08-29.
  45. ^ "S. Africa elephant culling splits wildlife groups". Associated Press. 2005-11-28. Retrieved 2010-08-29.
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