Risso’s Dolphin - Oceana

Marine Mammals

Risso’s Dolphin

Grampus Griseus


Worldwide in tropical to sub-polar latitudes


Coastal to open ocean (pelagic)

Feeding Habits

Active predator


Suborder Odontoceti (toothed whales), Family Delphinidae (dolphins)


Risso’s dolphins feed primarily on squid of all sizes (including the humboldt squid) and are therefore excellent divers, spending much of their feeding time at depth, hunting for their preferred prey. Scientists believe that much of the white scarring on the heads of these animals may be a result of aggressive interactions with large-bodied squids. Risso’s dolphins feed mostly at night, a probable result of the migration of their preferred prey to shallower waters in the dark. Scarring is also a likely result of interactions among adult males and between males and females.

This species, like all mammals, reproduces via internal fertilization and gives birth to live young, which nurse from their mothers for at least several months.

Though Risso’s dolphins are offered some or complete legal protection throughout much of their range, they are still hunted for food and for fertilizer in some places and are captured accidentally in fisheries targeting other species throughout most of their range. Current population trends are not known, but scientists believe the Risso’s dolphin to be common and to be a species of least concern. Further study of this species and monitoring of its populations is required to determine whether or not they are stable.

Engage Youth with Sailors for the Sea

Oceana joined forces with Sailors for the Sea, an ocean conservation organization dedicated to educating and engaging the world’s boating community. Sailors for the Sea developed the KELP (Kids Environmental Lesson Plans) program to create the next generation of ocean stewards. Click here or below to download hands-on marine science activities for kids.

Kids Environmental Lesson Plans

Additional Resources:

IUCN Red List

NOAA Fisheries