Mammals
Risso's Dolphin
Grampus griseus · also called Rissos dolphin, grey dolphin
Surfacing in deep ocean water, an old Risso’s dolphin displays a body covered almost entirely in pale scars, a lifetime of encounters with squid prey and fellow dolphins gradually turning its once-darker skin into a scarred, near-white canvas.
Overview
Risso’s dolphin, Grampus griseus, is a squid-hunting marine mammal native to deep ocean waters across a broad range spanning temperate and tropical regions of the Atlantic, Pacific, and Indian Oceans. Its extensive age-related scarring, distinctively blunt and beakless head, and specialised deep-diving squid hunting make it one of the more visually and behaviourally distinctive dolphin species found anywhere in the world’s oceans.
A life story written directly on the skin
Few dolphins carry as visible a record of their own history as Risso’s dolphin, whose accumulating scars from squid prey and social encounters gradually transform a young, darker individual into an old, nearly white one.
Status
Least Concern overall but decreasing in parts of its range, with declines linked to bycatch in fishing gear and other human-related pressures across some regions.
Risso's Dolphin: common questions
Why does Risso's dolphin get whiter as it ages?
This species accumulates extensive pale scarring across its body over its lifetime, largely from the beaks and suckers of squid prey as well as social interactions with other dolphins, causing older individuals to appear progressively whiter compared with the darker, less scarred skin of younger dolphins.
What does Risso's dolphin eat?
This species feeds heavily on squid, its primary prey, along with some fish, hunted primarily during deep dives in open water, often at night when squid rise closer to the surface and become more accessible.
How can you tell Risso's dolphin apart from other dolphin species?
Look for a distinctively blunt, rounded head without a pronounced beak, along with a vertical crease running down the centre of the forehead and extensive pale scarring across the body, features that together help distinguish this species from most other similarly sized dolphins.
How deep can Risso's dolphin dive?
This species is a capable deep diver, descending to considerable depths in pursuit of squid, an ability that reflects its specialised diet and sets it apart from dolphin species that feed primarily on fish closer to the surface.