Chimpanzees have secret handshakes!
Chimpanzees clasp hands while grooming one another, and each group has its own distinct grip, which researchers say is similar to a 'secret handshake' in humans. The apes are known to be a cultural species, and the new study by University of Antwerp scientists focused on hand clasping in two different groups over 12 years. This is a peculiar social custom among the chimpanzee species which is linked to grooming, but only found in a relatively small number of chimp populations.
Source: dailymail.co.uk