As is the case for humans, older chimpanzees have more mutual friendships of better quality than when they were younger. When they are young they are more eager to find friendships which can end up being one-sided and of poorer quality. The reason for this change in quality of friendships over the lifetime of a chimpanzee has been put down to (1) an emotional change (2) an “adaptive response” where older chimpanzees focus more on important social relationships which provide benefits. Unlike humans it has not been put down to an awareness of the passing of time and looking to the future. Humans tend to focus on less but higher quality friendships when they’re older because they can see the future and the limited time that they have left.
The study was carried out by researchers at the University of Michigan, Tufts University, Harvard University and University of New Mexico. They used information gathered over many years from the Kanyawara chimpanzee community living in Kibale National Park in Uganda.
Alexandra Rosati, a lead researcher, said that when people are younger they see the future as almost endless (“long and expansive”) and seek to find and build friendships but when they see their lifespan shortened they “focus more on close existing friendships”. They wanted to see whether the same process occurred in chimpanzees. They confirmed that it did but to put a spanner in the works, they also believe that chimpanzees are not able to consider themselves years ahead.
“There are some animals that can plan a couple of hours or days into the future. There is no sense that animals are able to consider themselves decades down the line”.
This is why they are yet to come to a firm conclusion why chimpanzees’ friendships alter throughout their lives as described. Comment: perhaps some research should be carried out on whether chimpanzees do indeed perceive their lifespan like humans and can foresee a shortened life due to the passage of time.
The researchers found that a 40-year-old chimpanzee had three times more mutual friendships and a third as many one-sided friendships compared to when there are 15-years-of-age.