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New England Seabirds

 Wilson's Storm-petrel  Dave Jones

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Dolphins & Porpoise

White-sided Dolphin
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Dolphins & Porpoises




Risso's Dolphin

Grampus griseus






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Risso's Dolphin Scott Spangenberg

Risso Dolphin mother and calf photographed on June 2010 BBC offshore pelagic. by Scott Spangenberg..The unscarred skin of the calf is dark.

Risso's Dolphin
Also commonly referred to by the genius Latin name "Grampus". Risso's Dolphin can be seen on offshore trips on the east and west coast.

Identification
The Risso's Dolphin has a beakless head and a tall falcate dorsal fin that is centrally located on the back. In a close view, you can observe a diagnostic crease in the forehead between the two eyes

The belly is white and the back gray. The body lightens with age and is often highly scarred by straight lines probably made by the teeth of other Risso’s Dolphins.. In adults the scarring may conceal the distinct border between the white belly and gray back.
Flippers are sickle shaped..

Behavior
Travels in pods of 3 or more animals.

Breeches (leaps from the water). Spy hops ( pushes head above the water). Seldom rides the bow wave of a moving boat.

Feeding
Primary food is squid and Risso’s usually feeds at night when the prey migrates to the surface. May take other cephalopods such as octopus and cuttlefish. ( Folkens 2002).

Range
Risso’s Dolphin is found in tropical and warm temperate waters of all oceans and large seas ( Mediterranean, Red). In some seasons occupies a niche descibed as the steep upper continental slopes, where water depths usually exceed 1000 feet. (Folkens 2002). This is probably why we see this dolphin on long pelagic trips to the canyons on the continental shelf south of Cape Cod.

 
Risso's Dolphin Glen Tepke California

This picture taken by Glenn Tepke off the coast of California shows the beakless head and scarring of the body of one individual and the tall dark dorsal fin of another.

Notice the lack of a beak and the sickle-shaped flippers. The upper jaw slightly overlaps the lower jaw.
This behavior is called “spy hopping”.

This picture taken by Glenn Tepke off the coast of California shows the beakless head and scarring of the body of one individual and the tall dark dorsal fin of another.

Notice the lack of a beak and the sickle-shaped flippers. The upper jaw slightly overlaps the lower jaw.
This behavior is called “spy hopping”.

Risso's Dolphin David Jones

Breeching Risso's Dolphin photographed by David Jones. Notice the tall falcate dorsal fin, the shape of the flippers, and the scarred gray skin..

Two  Risso's Dolphins  Scott Spangenberg

Two Risso’ Dolphins photographed by Scott Spangenberg. Notice the tall falcate dorsal fin and the scarred gray skin of the mother on the right..

Other Sea Life | Cetaceans  | White-sided | Common| Bottlenose | Risso's |Spotted & Striped | Harbor Porpoise  | Top of Page

Comments to webmaster

Folkens, Peter (2002) Guide to Marine Mammals of the World Alfred A. Knopf New York

Kinze, Carl Charistian (2001) Marine Mammals of the North Atlantic Princeton University Press Princeton NJ