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Apes Can Recognize Friends They Haven’t Seen in 25 Years, Study Finds



Quick Smiles:

  • Apes can recognize their old buddies even after not seeing them for over 25 years!
  • These furry friends respond with extra excitement to photos of their pals, just like we do when we see old friends.
  • These findings highlight the similarities between us and our primate relatives, especially when it comes to memory and social connections.

Hey there, animal lovers! Get ready for a tale that will tickle your funny bone and make you go “aww” at the same time. New research from Johns Hopkins University has revealed that apes can recognize their friends even if they haven’t seen them for decades. Yes, you read that right, decades!

This study has documented the longest-lasting non-human social memories ever recorded. It found that apes can recognize photos of their group mates they haven’t seen for more than 25 years. And guess what? They respond even more enthusiastically to pictures of their friends. Talk about #FriendshipGoals!

The researchers believe these findings highlight how human culture evolved from the common ancestors we share with these primates, our closest relatives.

“We tend to think about great apes as quite different from ourselves but we have really seen these animals as possessing cognitive mechanisms that are very similar to our own, including memory,” said Dr. Laura Lewis, a biological anthropologist at the University of California, Berkeley. She added, “I think that is what’s so exciting about this study.”

The idea for this study came from the researchers’ own experiences with primates. They felt that the animals recognized them when they visited, even if they’d been away for a long time.

Dr. Christopher Krupenye of Johns Hopkins, the study’s senior author, said, “You have the impression that they’re responding like they recognize you and that to them you’re really different from the average zoo guest. They’re excited to see you again.”

A particularly moving moment occurred in 2016 when a 59-year-old chimpanzee, the matriarch of the famous chimpanzee colony of the Royal Burgers Zoo in the Netherlands, was visited by Dutch biologist Jan van Hooff. The chimp, named Mama, hadn’t seen Jan for a long time, but her reaction to his presence was extremely emotional, touching the hearts of all the caregivers.


The researchers wanted to find out if apes really have a robust lasting memory for familiar social partners. The results showed that chimpanzees and bonobos recognize individuals they haven’t seen for multiple decades. There was a small but significant pattern of greater attention toward individuals with whom they had more positive relationships.

“It suggests that this is more than just familiarity, that they’re keeping track of aspects of the quality of these social relationships,” said Dr. Krupenye.

The study was conducted at three locations: Edinburgh Zoo in Scotland, Planckendael Zoo in Belgium, and Kumamoto Sanctuary in Japan. The researchers collected photographs of apes that had either left the zoos or died, and information about the relationships each participant had with former group mates. The apes were then shown two side-by-side photographs—apes they’d once known and total strangers—while they sipped juice. Using a non-invasive eye-tracking device, the team observed that the apes looked significantly longer at former group mates, no matter how long they’d been apart. And they looked even longer at their former friends.

The study suggests that great ape social memory could last beyond 26 years, the majority of their 40- to 60-year average lifespan, and could be comparable to that of humans. This kind of long-lasting social memory was likely already present millions of years ago in our common evolutionary ancestors.

The research also raises the question of whether the apes miss individuals they’re no longer with, especially their friends and family.


“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,” said Dr. Lewis.

So, next time you’re reminiscing about old friends, remember that you’re not alone. Our primate pals do it too! Now, isn’t that something to smile about? Share this fun fact and the beautiful video with all the animal lovers you know!