There is more to aging than just gray hair and wrinkled skin. When people reach their next years they favor more established friends and their social circle is soothed.

Now, for the first time to appear, scientists have observed the same behavior in another species. More than two decades of observation of chimpanzees have shown that older males prefer to hang out with long-term friends at the expense of their relationships.

“What we’ve shown is that chimpanzees and humans share the same pattern of social age,” said Jerin Machanda, a primologist at Tufts University in Massachusetts. “We know that over the ages their social networks have shrunk but their social bonds have grown stronger and in chimpanzees we see the same thing here.”

Researchers observed 78,000 hours between 1995 and 2016, following the social interactions of 21 male chimpanzees between the ages of 15 and 56 in Uganda’s Qibla National Park. They focused on men because they had stronger social ties than girls and interacted more often.

Working with Alexandra Rozati and others at the University of Michigan in Ann Arbor, Machanda categorized Shimp’s relationships based on the amount of time she spent tying up with others and creating them. They then rated the various pairs as mutual friendships, where both shimps seem to have enjoyed the relationship; One-sided friendship, where one shimp was more interested in being a friend than the other; And friendshiplessness, where chimps both show no interest in the other.

When the scientists looked at the patterns of friendship, they found that the old chimpanzees had more mutual and one-sided friendships than the small chimps. For example, a 40-year-old man had three times more mutual friendships than a 15-year-old and a third had fewer one-sided friendships.

Another feature seen in older people was also seen in beans. As men get older, their level of aggression becomes tighter, which means they started fighting less and often intimidated others in their group. “They show a shift towards more positive behavior,” Machanda said.

Observational researchers have been surprised. According to a concept in psychology known as the EarthSomotive Selectivity Theory or SST, older people prefer more positive relationships because they are aware that time is running out. Many primatologists, however, argued that chimpanzees lack a sense of human death, behaving differently when advised to do something else.

According to Machander, research published in Science has shown that social circles do not need an idea of ​​the future to shrink with age, and other factors may ignore behavior between humans and snails.

Robin Dunbar, a professor of evolutionary psychology at Oxford University, rather rejected the theory of socioeconomic consciousness and said that it sounded like an “innocent attitude”. “In humans, fall [in social circles with age] Lack of opportunities to meet people and reduce social motivation to meet them, ”he said.

In the wake of similar behavior between Chimps and humans, Joan Silk, an anthropology professor at Arizona State University, said it could have originated in humans before they develop modern cognitive skills and the ability to destroy future events.

Older men tend to focus less on intimate, reciprocal relationships with trusted partners because they compete less for partners, he said.

Or as Machanda says: “They can be very happy together.”