Risso Dolphin
Common Name:Risso's dolphin
Latin Name:Grampus griseus
Other Names:Grey dolphin, White-head grampus, Grey grampus
Primary Classification:Odontocete (Toothed whale, dolphin or porpoise)
Sub Classification:Delphinidae
Description:
Risso's dolphins are quite easy to identify, especially when they get older. This is because they become scarred and battered due to being scratched by the teeth of other Risso's dolphins. They only have teeth in the front of their lower jaw and these are used when playing or fighting. When born they are grey all over, and then become chocolate-brown and eventually pale grey with a pale underside. Their flippers and tail remain darker though, and the flukes are broad with pointed tips. They have a very tall dorsal fin which can be up to 50cm in length, the tip of which may be curved or pointed. Instead of a beak, it has a blunt head with bulging forehead that slopes steeply to the mouth which curves upwards
Field ID:
Robust body, abrupt forehead, single blowhole, grey in colour, lighter under-side (belly), tall dorsal fin, white scratches and scars.
Length (metres):
Adults range from about 2.6 to 3.8m (8.5 to 12.5ft), and new-borns from 1.3 to 1.7m (4.25 to 5.75ft).
Weight:
Adults weigh 300 - 500kg
Diet:
Fish, squid
Behaviour:
Risso's do not often 'bow- ride' in front of boats, but may swim beside or in the bubbly wake that a boat leaves. They generally swim in groups of between 3 and 50 animals. These groups spread out in a long line when hunting for food. Some groups are shy, but some allow humans to approach close to them. Young animals are energetic, and may breach (lift themselves out of the water), slap their flippers against the surface of the sea, 'spyhop' (lift their head above the surface to have a look around), and surf in the waves.