Do other primates adopt pets?

This is a fascinating video, perhaps portraying a situation that might help us understand our own domestication of dogs. But part of me thinks this is just kind of the product of abnormal conditions: feral dogs are abnormally preadapted to life in any social group, and garbage dumps provide abnormal resource conditions allowing this odd interspecies interaction to go on.

Is this, however, a true mutualism? I am not seeing much in the video to suggest that the baboons and dogs provide each other with the unique benefits typical of an interspecies mutualism. This seems more like social group confusion to me.