Apes Reunite with Long-Lost Friends, Study Reveals
New research reveals that apes possess an extraordinary ability to recognize and remember long-lost friends, even after decades of separation This remarkable social memory is unparalleled among non-human species
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New research shows that apes can remember old friends they haven't seen in decades, marking the longest social memory ever recorded outside of humans.
The study published in the Proceedings of the National Academy of Sciences revealed that chimpanzees and bonobos could recognize photos of former groupmates over 25 years later, with pictures of old friends evoking an even more positive response. Christopher Krupenye, an assistant professor at Johns Hopkins University and senior author of the study, shared that his inspiration for the research came from his observations of apes recognizing him years after their last interaction.
The study found that both chimpanzees and bonobos recognize old friends, even after decades apart.
Kate Grounds from the Edinburgh Zoo was involved in a study conducted by Krupenye and lead author Laura Lewis, a biological anthropologist and comparative psychologist at the University of California, Berkeley. They tested their hypothesis using photographs of apes from Edinburgh Zoo in Scotland, Planckendael Zoo in Belgium, and Kumamoto Sanctuary in Japan.
The team chose people the apes hadn't seen in varying time periods from nine months to 26 years, with high-quality images available. They recorded the type of relationship the apes had with these individuals. The researchers then presented the apes with two photographs - one of a familiar ape and another of a stranger. They used a noninvasive eye-tracking device to measure the apes' gaze and duration of their gaze.
The study's findings indicated that the apes gazed "considerably longer" at individuals they were familiar with, regardless of the length of time since their last interaction, and even longer at those they had established a friendly relationship with.
Krupenye likens the experience to bumping into someone from high school in the street after not seeing them for years.
"Its a very familiar experience for humans too," he told CNN.
Ability to miss loved ones?
During the test, it was found that one bonobo named Louise had not seen her sister Loretta or nephew Erin for 26 years. Despite this, she exhibited a strong preference for both of them over eight trials, as reported in a news release.
The research suggests that the social memory of apes may surpass 26 years and could potentially rival that of humans. Humans tend to forget individuals after 15 years, but can retain memories for as long as 48 years, as mentioned in the report.
researcher, commented that this behavior could be a form of sharing or altruism, showcasing the complex social dynamics within chimpanzee communities.
Chimpanzees share experiences with each other, a trait once thought to be only human
"This seems to be approaching sort of life-long memory for these animals," Krupenye told CNN.
New research indicates that nonhuman animals, particularly dolphins, have an impressive social memory, with records showing dolphins remembering individuals after 20 years. This suggests that social memory is a trait shared with our closest relatives, rather than evolving separately in humans, according to the researchers.
The study suggests that apes may have the ability to experience emotional longing for their loved ones, which challenges the belief that this is a uniquely human trait. Lead researcher Lewis stated, "The idea that they do remember others and therefore they may miss these individuals is really a powerful cognitive mechanism and something that's been thought of as uniquely human."
While our study does not definitively prove their actions, it does prompt speculation about their potential capability. The authors aim to bring attention to the impact of poaching and deforestation on ape communities, emphasizing the importance of conservation efforts to mitigate these effects.
This photo shows a chimpanzee female, Roxy, applying an insect to a wound on the face of an adult chimpanzee male named Thea.
From Tobias Deschner
Chimpanzees apply medicine to each others wounds in a possible show of empathy
Lewis emphasized the importance of these results in fostering empathy for our closest living cousins, and warned that the bonobos could face extinction within our lifetime. Moving forward, the team aims to explore the apes' ability to recognize former friends as they currently appear, and to investigate whether other primates, such as gorillas and orangutans, also possess long-lasting social memories.
"We may very well observe similar effects in other apes," Krupenye mentioned, implying that their approach could be applied to studying social memory in other animals, including sheep and dogs.
