Gimme five!(NEWS & TREND) (chimpanzees' secret handshakes) (Brief article)

It's long been known that chimps are very social. It turns out some, like these half brothers at a zoo in Denmark, have their own secret handshakes. They exchange handshakes while grooming-picking insects and debris from their fur-an important bonding activity for chimps. Only some groups of chimps have handshakes, and they vary among groups. In addition, they seem to be passed on from generation to generation. All this suggests the...