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Risso's Dolphin - Grampus griseus
Photo by Andy Collins

Risso’s dolphins are one of the larger dolphins and have a distinctive rounded head and very tiny rostrum. Males can reach lengths of 3.8 meters long. Key identification features of these cetaceans are their blunt heads and unique coloration created by heavy scarring. At birth, the dolphins are dark gray to black, but as they age these cetaceans become white with scars created in part by sparring with other dolphins. The elders in a pod may even appear ghostly white. Risso’s tend to swim in deep water and stay within localized regions.

Risso's Dolphin
(Grampus griseus)

Deep tropical and temperate waters of the world’s oceans

Risso’s dolphins prefer deeper offshore waters but can be seen inshore around oceanic islands and along the edges of the continental shelf.

Squid and occasionally fish


The status of this species is representative of the populations within the waters of this Sanctuary only, not global populations.

Quick Fact
The scars on Risso's come from sparring with other Risso's, and to a lesser degree from squid, which are their favorite food.

Learn More
- The American Cetacean Society
- Kids Do Ecology: NCEAS
- Cetacea