White dolphin in Monterey Bay

A rare white dolphin has been spotted in the waters off the California coast

A whale watching boat noticed the white juvenile Risso’s dolphin swimming with its mother in a large pod last week. The youngster was first seen in 2014 shortly after it was born, and then again two years ago. It’s thought that this dolphin is the only white member of its species in the East Pacific.

(Video: Princess Monterey Whale Watching)

The young dolphin could be either albino or leucistic. Albinism results from the complete lack of the pigment melanin in an animal. Pigments are substances produced by the body which reflect certain wavelengths of light which are interpreted as a particular colour. The eyes of albino animals (including people) appear pink because the lack of pigment in the irises allows the blood vessels of the retina to show through.

Leucism is a similar condition, where a white or pale animal results from a partial loss of colour. Unlike albinism, however, this can be caused by the lack or loss of multiple pigment types. Most leucistic animals have normal eye colour.

Albinism and leucism can both reduce the fitness of an animal, because they are more vulnerable to UV rays and predation. The yellow colour is cause by a type of algae that grows on the dolphins.

 

Risso’s dolphin is the only species in its genus. These dolphins have bulbous heads with a vertical crease and no distinguishable beak. Adults average three metres (10 feet) in length, and are usually covered in long straight scars from the teeth of other Risso’s dolphins. They feed largely on squid, and feisty prey can add to the scars before being dispatched by the dolphin’s four to fourteen teeth (all in its lower jaw). Mother dolphins and their calves often group together in nursery pods, travelling in groups of up to 400 (sometimes including other marine mammal species).

 

 

 

(Feature photo: Kate Cummings – Blue Ocean Whale Watch)