rissos | San Diego Whale Watch 1

Risso’s Dolphin

Grampus griseus


10-13 feet (3-4 m)


650-1,100 pounds (300-500 kg)


Prefer offshore habitats in warm temperate and tropical waters in both hemispheres


Unknown worldwide, approximately 15,000-30,000 off the coast of California


Risso’s Dolphins are one of the larger members of the dolphin family. They are dark gray in color with extensive white scarring along their bodies. The scars are mainly caused by their primary food source, squid, which utilize defensive sharp hooks on their tentacles. The scarring may also be caused by “raking” or biting from other Risso’s Dolphins.

Risso’s Dolphins typically travel in groups of 3-30 animals, although megapods of more than 1,000 have been reported. Little is known about this species, due to the fact that they are a pelagic species and are often found a very long way from shore.