Why elephants never forget - Alex Gendler

8,793,572 views ・ 2014-11-13

TED-Ed


Please double-click on the English subtitles below to play the video.

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It's a common saying that elephants never forget,
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but these magnificent animals are more than giant walking hard drives.
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The more we learn about elephants,
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the more it appears that their impressive memory
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is only one aspect of an incredible intelligence
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that makes them some of the most social, creative,
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and benevolent creatures on Earth.
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Unlike many proverbs, the one about elephant memory
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is scientifically accurate.
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Elephants know every member in their herd,
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able to recognize as many as 30 companions by sight or smell.
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This is a great help when migrating
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or encountering other potentially hostile elephants.
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They also remember and distinguish particular cues that signal danger
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and can recall important locations long after their last visit.
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But it's the memories unrelated to survival that are the most fascinating.
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Elephants remember not only their herd companions
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but other creatures who have made a strong impression on them.
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In one case, two circus elephants that had briefly performed together
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rejoiced when crossing paths 23 years later.
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This recognition isn't limited to others of their species.
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Elephants have also recognized humans they've bonded with after decades apart.
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All of this shows that elephant memory goes beyond responses to stimuli.
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Looking inside their heads, we can see why.
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The elephant boasts the largest brain of any land mammal,
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as well as an impressive encephalization quotient.
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This is the size of the brain relative to what we'd expect
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for an animal's body size,
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and the elephant's EQ is nearly as high as a chimpanzee's.
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And despite the distant relation,
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convergent evolution has made it remarkably similar to the human brain,
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with as many neurons and synapses
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and a highly developed hippocampus and cerebral cortex.
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It is the hippocampus, strongly associated with emotion, that aids recollection
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by encoding important experiences into long-term memories.
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The ability to distinguish this importance makes elephant memory
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a complex and adaptable faculty beyond rote memorization.
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It's what allows elephants who survived a drought in their youth
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to recognize its warning signs in adulthood,
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which is why clans with older matriarchs have higher survival rates.
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Unfortunately, it's also what makes elephants one of the few non-human animals
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to suffer from post-traumatic stress disorder.
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The cerebral cortex, on the other hand, enables problem solving,
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which elephants display in many creative ways.
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They also tackle problems cooperatively,
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sometimes even outwitting the researchers and manipulating their partners.
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And they've grasped basic arithmetic, keeping track of the relative amounts
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of fruit in two baskets after multiple changes.
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The rare combination of memory and problem solving
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can explain some of elephants' most clever behaviors,
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but it doesn't explain some of the things we're just beginning to learn
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about their mental lives.
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Elephants communicate using everything from body signals and vocalizations,
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to infrasound rumbles that can be heard kilometers away.
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And their understanding of syntax suggests that they have their own language and grammar.
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This sense of language may even go beyond simple communication.
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Elephants create art by carefully choosing and combining
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different colors and elements.
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They can also recognize twelve distinct tones of music and recreate melodies.
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And yes, there is an elephant band.
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But perhaps the most amazing thing about elephants
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is a capacity even more important than cleverness:
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their sense of empathy, altruism, and justice.
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Elephants are the only non-human animals to mourn their dead,
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performing burial rituals and returning to visit graves.
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They have shown concern for other species, as well.
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One working elephant refused to set a log down into a hole
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where a dog was sleeping,
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while elephants encountering injured humans have sometimes stood guard
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and gently comforted them with their trunk.
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On the other hand, elephant attacks on human villages
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have usually occurred right after massive poachings or cullings,
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suggesting deliberate revenge.
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When we consider all this evidence,
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along with the fact that elephants are one of the few species
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who can recognize themselves in a mirror,
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it's hard to escape the conclusion
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that they are conscious, intelligent, and emotional beings.
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Unfortunately, humanity's treatment of elephants does not reflect this,
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as they continue to suffer from habitat destruction in Asia,
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ivory poaching in Africa, and mistreatment in captivity worldwide.
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Given what we now know about elephants
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and what they continue to teach us about animal intelligence,
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it is more important than ever to ensure
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that what the English poet John Donne described as "nature's great masterpiece"
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does not vanish from the world's canvas.
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