There are many examples of how [our behavioural heritage from chimpanzees] can create trouble in our relationships with dogs. For example, humans love to hug. It's called "ventral-ventral contact" in the primate literature, and chimps and bonobos love to do it too. They hug their babies, and babies hug them. Adolescent chimps hug each other, and so do adult chimps when they're reconciling from conflict. (..). Try telling an adolescent girl, or any four-year-old, not to hug her beloved dog. Good luck. But dogs don't hug. (..). Dogs are just as social as we are, veritable social butterflies who can't live a normal life without a lot of social interaction. But they don't hug. And they often don't react kindly to those who do. Your own dog may benevolently put up with it, but I've seen hundreds of dogs who growled or bit when someone hugged them.

— The Other End of the Leash by Patricia B. McConnell (Page 1)