Risso's dolphin

Risso's dolphin (Grampus griseus) is the only living species in the genus Grampus, a member of the oceanic dolphin family Delphinidae closely related to pilot whales, pygmy killer whales, melon-headed whales and false killer whales. Adults reach about 10 feet in length, occasionally up to 13 feet, and weigh 660 to 1,100 pounds, making them among the heaviest dolphins. Their skin is covered in extensive white scarring, with calves born gray brown and cream that grow paler with age until many older animals are almost entirely white. The species lives in cold to temperate waters worldwide across the Atlantic, Pacific and Indian Oceans and connected seas such as the Mediterranean and Baltic, generally over continental shelf waters 1,300 to 3,300 feet deep, though it can dive to 2,000 feet chasing prey. It feeds mainly at night on squid and octopus using echolocation, and is listed as Least Concern by the IUCN, though it faces threats from fishing nets, whaling, pollution and underwater noise.