Extremely rare all-white dolphin 'Casper' spotted off California coast

MONTEREY BAY, Calif. (KABC) -- A whale watching crew recently got a special treat when a rare, all-white risso's dolphin made an appearance near their boat.

The beautiful dolphin, who they nicknamed "Casper," is either albino or leucstic, both conditions that cause a reduction in the pigment of their color.

There are only three known all-white risso's dolphins in the entire world.

A risso's dolphin is a species of dolphin often seen around Monterey Bay, and is distinguished by its circular face.