Chimpanzees at a zoo were shown photos of old group members to test their memory.
Johns Hopkins University
Bonobos and chimpanzees appear to be able to recognize photos of former group members, even animals they haven’t seen in over 20 years. This means that these apes have the longest social memory of any non-human animal.
Great apes such as gorillas, chimpanzees, and bonobos are known to have impressive memories. For example, some chimpanzees The exact location of a particular fruit tree In the forest, predict what will happen next in a previously seen movie. The researchers also found hints that great apes have long-term memories of individuals.
“When we went back to great ape populations that we had studied in the past, we noticed that they seemed to recognize and remember us,” he says. laura lewis at the University of California, Berkeley.
To investigate how long this social memory lasts in great apes, Lewis and her colleagues tested 12 bonobos and 15 chimpanzees living in zoos in the UK, Japan, and Belgium.
For each animal, the researchers flashed side-by-side photos of two different great apes on a screen for three seconds. One of the photos was of a monkey that had been living with them for at least a year, and the other was of a stranger.
Using eye-tracking technology, the researchers found that all participants looked on average about a quarter of a second longer at images of former group members than at images of strangers. As zookeepers say, former co-workers with whom they had a good relationship stay in the picture even longer.
This finding shows that these apes remember their acquaintances even after long periods of time. “It’s not that different from walking down the street in a big city and unexpectedly running into someone you went to school with and doing a double take,” team members say. Christopher Krupenier at Johns Hopkins University in Maryland.
In the most extreme case, a bonobo called Louise appeared to recognize her sister Loretta and nephew Erin after being separated for more than 26 years.
“This is the longest long-term social memory ever recorded in a non-human animal,” Lewis said.
topic:
Source: www.newscientist.com
