How old is the oldest kiss? Well, the answer to that depends on your starting point!

A new study looked at ���kissing��� in the animal kingdom. Scientifically defined, a kiss is ���non aggressive, directed oral-oral contact ���with some movement of lips or mouthparts and no food transfer.������

By this definition, the behavior of ���kissing��� is seen in many species, including great apes, dogs, polar bears, prairie dogs, and even the albatross. The researchers also note that Neanderthals and mod...