RISSO'S DOLPHIN

Grampus griseus

Risso’s dolphins are easily recognized by their blunt heads (no beak) and heavily scarred bodies, which become paler with age. These scars are mostly from interactions with other dolphins and squid—especially from the tentacle hooks of their prey. Risso’s dolphins feed almost exclusively on cephalopods, particularly deep-sea squid. They are deep divers, capable of descending over 600 meters to hunt in the mesopelagic zone. They are found in temperate and tropical oceans worldwide, typically in deep offshore waters near the continental shelf or slopes. However, they may occasionally venture closer to shore where deep water is accessible—such as near the Azores or southern Portugal. Risso’s dolphins are social animals, usually found in small to mid-sized groups. Calves are born dark grey, but as they age and accumulate scars, adults can appear almost white—especially older individuals. Risso’s dolphins are less vocal than species like bottlenose or common dolphins. In Portugal, especially around the Azores and sometimes in the south near the Algarve, Risso’s dolphins can be observed, particularly in spring and summer, when deep-diving prey may be more accessible.