It turns out that chimpanzees and gorillas can form lasting friendships

It's a good idea to have friends who know where to get free food.

Chimpanzees and gorilla can be friends with advantages for everyone. There is a new paper in the journal iScience that looks at the social interactions between primate species over the course of two decades.

gorillas follow the sound of chimps to a canopy full of ripe figs and then co- feed at the same tree over the course of 20 years. Young people of both species were interacting with each other in ways that can foster their development. When the two species encountered each other, gorillas and Chimpanzees scanned the others and then approached the ones they knew the best.

Chimpanzees are known to beat their chests, a behavior associated with gorilla.

It was thought that associations between the species could be used to avoid predatory animals. The behavior of the apes did not show that was a factor in their interactions.

Crickette Sanz, a primatologist at Washington University, said in a news release that Chimpanzees have been killed by leopards in the area. The number of Chimpanzees in daily subgroup is relatively small and they are far from the silverback who is thought to be a protectors from predatory animals.

Better foraged seemed to be a key upside for both species, as they would often eat at the same tree.

Some interactions were not warm and friendly. The study notes that "Interspecific aggression was often consisted of threats, but it never rose to the level of lethal aggression that has occurred between Chimpanzees andGorillas in Gabon."

Disease transmission is a risk from these social interactions. Thousands of gorilla were killed in central Africa in the 1990's due to an outbreak of the disease.

The research makes a case for what can be learned from long-term studies of these animals.

Jake Funkhouser, a PhD candidate of biological anthropology at Washington University, said that no longer can we assume that an individual ape's social landscape is entirely occupied by members of their own species. The strength and persistence of social relationships that we observed between apes indicates a depth of social awareness.