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Marine Animal 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.

Risso’s Dolphinzoom image
  • Order Cetacea
  • Length 10–14 ft (3–4.3 m)
  • Weight Up to 1,100 lb (500 kg)
  • Habitat Deep water
  • Distribution Ropical and warm-temperate waters worldwide
Risso’s Dolphin habitat mapzoom image