Risso’s Dolphin |Sanctuaire pour les mammifères marins Agoa

(Grampus griseus)

Identity card

Taxonomy

Order: Odontocetes
Family: Delphinidae
Species: Grampus griseus

Measurements

2.6 to 5 m, weighing 300 to 500 kg

Lifespan

Up to 35 years

IUCN status

Least Concern
(International Red List)

Not Evaluated
(Martinique 2020 Red List, Guadeloupe 2022 Red List)

Habitat

A pelagic species, Risso's Dolphin lives at depths between 400 and 1000 metres. It can occasionally be seen near the coast. It migrates between summer and winter according to variations in water temperature. It is found in temperate, subtropical and tropical oceans.

Reproduction

It gives birth to a calf every 2 to 4 years after a 14-month gestation period.

Diet

The Risso's Dolphin is a carnivore and feeds on molluscs, fish, crustaceans and krill.

Morphological characteristics for distinction at sea

Head: rounded with a distinct melon and an undiscernable beak, presence of a concave groove between the mouth and the melon
Fins and flippers: big sickle-shaped dorsal fin, long pointed and curved pectoral fins, pointed caudal peduncle with a pronounced central notch
Colouring: silver-grey to almost black back, white areas on belly, the body increasingly whitens with age with an accumulation of white linear scars mainly on the back and flanks