"The discovery of a new bone in a new species is a rare event, especially in chimps which have such similar anatomy to people," researcher Catrin Rutland said.
Dr. Roman Wittig thinks that "spatial distancing" would be a better term to use, since socializing brings benefits that are necessary, particularly during a global pandemic.
Krefeld Zoo in Germany said chimpanzees, orangutans, gorillas, fruit bats and birds were among the estimated 30 animals killed.
Scientists also observed the chimps sharing the tortoise meat between individuals.
Using tools to dig for food underground was once thought to be a behavior unique to humans.
The results could have important implications for understanding when humans and other great apes diverged in evolutionary terms.
"It's likely that all great apes can understand at least some of this system of gestures."
Chimps beat us to the friendship game.