The Gray Whale or Grey Whale (Eschrichtius robustus) is a whale that travels between feeding and breeding grounds yearly. It reaches a length of about 16 meters (52 ft), a weight of 36 tons and an age of 50???60 years. Gray Whales were once called Devil Fish because of their fighting behavior when hunted. The Gray Whale is the sole species in the genus Eschrichtius, which in turn is the sole genus in the family Eschrichtiidae. This animal is one of the oldest species of mammals, having been on Earth for about 30 million years. In the remote past it was preyed upon by Megalodon sharks (which are now extinct).