This social behavior might reveal the evolutionary roots of traits that underlie pet-keeping in humans, scientists say, from caregiving to tolerance and curiosity. But it's not the same as a person keeping a cat or a dog
Ishe and Dembe, two young eastern chimpanzees, jumped from branch to branch into the dense vegetation of a reserve in Uganda when they surprised the researchers who watched them. The couple approached a nearby red-tailed monkey, but not aggressively, as often happens among chimpanzees, but with caresses. Ishe and Dembe began to comb the monkey's tail calmly. An interaction as singular as this could represent an early stage of pet-care behavior i…