Grampus griseus - Dauphin de Risso ou Grampus - Grampo grigio - Risso’s dolphin
Illustration © M. Würtz. Musée océanographique de Monaco, Fondation Albert Ier

Risso’s dolphins are around 3 m long, and vary in weight between 250 and 400 kg. Young Risso’s dolphins are grey, but their bodies are marked by scars, the result of competing for mates and other social activities while coming of age, while the oldest Risso’s dolphins become completely white (at around forty years old). These cetaceans have no rostrum. It is estimated that the population in the northwestern Mediterranean is composed of around 3,000 individuals, most often found at depths of between 600 and 1,000 m, along the continental shelf and above underwater canyons and cliffs. They feed on squid and are seen in the Sanctuary all year round.