They say “an elephant never forgets.” But how much truth is there in that expression? How good is the memory of an elephant?
Although it is not strictly speaking accurate to say that an elephant never forgets, pachyderms evolved to remember details that are key to their survival. For example, older African elephants (Loxodonta africana) can remember the unique sounds and smells of predators (even discriminate between different groups of people, depending on smell and color of clothes (opens in a new tab)), retrace their steps to find waterholes in the dry savannah, separating family members and associates from hundreds of other elephants.
“Being able to find enough food and water in a highly dynamic environment like the savanna, while managing complex social relationships and avoiding predation risk, requires a brain capable of processing and remembering detailed information.” Graeme Shannon (opens in a new tab), a lecturer in zoology at Bangor University in the United Kingdom, told LiveScience in an email. “This is a critical skill that can mean the difference between life and death.”
Elephants aren’t the only animals that forage for food on the savannah, but the unique challenges these pachyderms face require exquisite memories. For example, each elephant needs to eat approx 330 pounds (opens in a new tab) (150 kilograms) of vegetation every day, and to satisfy their voracious appetites, elephants embark on long migration routes between the wet and the dry. seasons. Whether they survive this migration depends heavily on their knowledge of the route.
“An elephant’s memory makes it easier to remember long migration routes that include wood and water resources, which are important for getting through a very long migration,” Caitlin O’Connell (opens in a new tab)a Harvard Medical School faculty member who studies elephant hearing told LiveScience in an email.
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Memory becomes especially important during a drought. A study from 2008 in the journal Biology letter (opens in a new tab) observed that elephant herds with older matriarchs, who had lived through previous droughts, led their herds to water – presumably by remembering how the herd had survived the previous drought.
However, one herd was led by a young matriarch who could not have remembered how the previous generation had dealt with the last drought. Her herd stayed rather than travel through new terrain to find water, and the calves suffered a 63% mortality rate that year. The normal mortality during a drought is only 2%. “Hence the importance of older matriarchs as important repositories of knowledge,” said O’Connell, who was not involved in the study. “And hence why long-term memory can lead directly to survival.”
Elephants also need their memories to navigate what biologists call a “fission-fusion dynamic.” In this arrangement, which is also common among primates and some cetacean species, a nuclear family unit of elephants comes into contact with hundreds of other elephants during the year (fusion), only to later break out into the same core group (fission).
“Operating in a highly complex social world requires significant brain power,” Shannon said. “It is critical that elephants have detailed knowledge of familiar families and close associates, as well as being able to identify strangers and be more cautious when interacting with these unfamiliar individuals,” who can act aggressively and pose a threat to the family unit.
Unknown elephants aren’t the only threats these pachyderms need to keep in mind to survive. Shannon co-authored a 2011 study in the journal Proceedings of the Royal Society B: Biological Sciences (opens in a new tab) which showed that younger elephants underreact to recorded sounds of roaring males lionswhile older elephants (who would remember previous lion attacks) adopt defensive positions in response to the roars.
In another study, published in the journal Proceedings of the National Academy of Sciences (opens in a new tab) in 2014, Shannon and colleagues demonstrated that elephants can also identify the voices of humans that pose a threat. They found that elephants are more likely to take precautions when they hear the recorded voices of semi-nomadic Masai people, who regularly kill elephants, than the voices of other Kenyan ethnicities. The elephants were also more likely to defend themselves when they heard the recorded voices of Maasai men, as opposed to recordings of Maasai women and children. “The incredible memories and cognitive abilities of elephants have even enabled them to use human language to determine the threat posed by different groups of people,” he said.
Elephants’ unique brain structures may be what enable them to perform these impressive feats of memory and cognition. A series of studies (opens in a new tab) performed by Bob Jacobs (opens in a new tab), a professor of psychology who specializes in neuroscience at Colorado College, has shown that elephants’ cortical neurons are radically different from other intelligent species. Jacobs believes that the unique properties of these neurons suggest that elephants carefully ponder their memories. “In terms of cognition,” he wrote in The conversation (opens in a new tab)“my colleagues and I believe that the integrative cortical circuits in the elephant support the idea that they are essentially contemplative animals.”
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Elephants have too the largest absolute brain size (opens in a new tab) among land mammals, and the largest temporal lobe relative to body size; The temporal lobe is the part of the brain responsible for processing sounds and encoding memory.
The fact that elephants are so dependent on memory makes conservation all the more necessary. When poachers target the biggest elephants with the biggest tusks, they usually place the oldest elephants in their sights – stores of the herd’s collective memory – and these losses mean younger elephants are left to a herd with which they have no experience. to lead to safety in the dry season.
Likewise, if the survival of elephants depends on elders remembering migration routes, development that alters the landscape and cuts off important paths can have devastating consequences for entire herds. “Their habitat is threatened by human development that blocks important migration routes, leaving them confined to marginal lands that often lack essential resources needed to survive long dry seasons,” O’Connell said. “One obvious implication is the importance of preserving critical migration routes.”