A study has revealed that they can remember another bonobo or chimpanzee for more than 25 years.
Researchers used infra-red eye-tracking cameras to record where the primates gazed when they were shown side-by-side images of other bonobos or chimps.
One picture was of a stranger, while the other was of a bonobo or chimp the participant had lived with for a year or more at some point in their life.
They found the apes’ eyes lingered significantly longer on images of those with whom they had previously lived, suggesting some degree of recognition.
They also looked longer at apes with whom they’d had more positive relationships.
Researchers found the apes’ eyes lingered significantly longer on images of those with whom they had previously lived, suggesting some degree of recognition
In one case, a bonobo named Louise (not pictured had not seen her sister or nephew for more than 26 years, when the researchers showed her their images, her eyes honed in on both of them
The findings also bolster the theory that long-term memory in humans, chimpanzees and bonobos likely comes from our shared common ancestor that lived between 6 million and 9 million years ago
In one case, a bonobo named Louise had not seen her sister or nephew for more than 26 years. When the researchers showed her their images, her eyes honed in on both of them.
Dr Laura Lewis, from the University of California, Berkeley, said: ‘These animals have a rich recognition of each other. We don’t know exactly what that representation looks like, but we know that it lasts for years.
‘This study is showing us not how different we are from other apes, but how similar we are to them and how similar they are to us.’
Previous research has shown dolphins can recognise one another’s signature calls for up to 20 years. ‘Until this point, that has been the longest long-term social memory ever found in a non-human animal,’ Dr Lewis said.
The findings also bolster the theory that long-term memory in humans, chimpanzees and bonobos likely comes from our shared common ancestor that lived between 6 million and 9 million years ago.