Marine Wildlife Encyclopedia
Risso's Dolphin Grampus griseus
Also known as the gray grampus, this large dolphin is typically blackish blue with a square head that is quite different from the pointed heads of beaked dolphins.
Close up, this dolphin’s skin often appears scarred, especially in older individuals. Scarring is mainly due to fights between rivals, but some of it is due to encounters with squid, which make up a large proportion of its prey. When feeding, it can dive for up to half an hour. Risso’s dolphin is less sociable than many other dolphins, but it often swims alongside ships.