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group of Pacific white-sided dolphins

Learn More About White-Sided Dolphins

Pacific white-sided dolphins are named for their distinctive coloring – their bodies are dark gray or black, with a striking white or light gray patch on each side. As medium-sized dolphins, these animals can reach up to 400 pounds and 8 feet in length, with males typically being larger than females.

They are considered robust animals, with a large and strongly curved dorsal fin. Unlike bottlenose dolphins or common dolphins, Pacific white-sided dolphins have a small and unnoticeable beak.

Pacific white-sided dolphin spyhopping
Pacific white-sided dolphin leaping out of the water

Habitat & Population Status

Pacific white-sided dolphins are found in the cold, temperate waters ranging from North America to Asia. In November to April, these dolphins can be seen in nearshore waters off of Southern California. In May they can be found off of Oregon and Washington, which leads scientists to believe that the population migrates seasonally in this manner.

Outside the United States, Pacific white-sided dolphins can be found near the Aleutian Islands and around Japan. There are three stocks of Pacific white-sided dolphins in United States waters, two of which have been surveyed for population estimates. While it’s unknown how many of these dolphins reside in Alaskan waters, it’s estimated that more than 21,000 individuals are found off the coasts of Washington, Oregon and California.

Pacific white-sided dolphin leaping out of the water
pod of Pacific white-sided dolphins
Pacific white-sided dolphin leaping out of the water
a group of Pacific white-sided dolphins

For the Aspiring Scientist: Marine Mammal Poster

This dazzling poster is a must-have for any marine mammal enthusiast. Illustrated in meticulous detail by an award-winning marine mammal illustrator, this poster showcases over 30 types of marine mammals, including the Pacific white-sided dolphin, found along the California coast. An aspiring scientist is sure to feel inspired with this hung on their wall.

Marine Mammals of the California Coast poster

Breeding & Behavior

Once female Pacific white-sided dolphins reach sexual maturity around 8 to 11 years old, they usually give birth every three years. After a pregnancy of about 12 months, females give birth from April to August. Newborns weigh about 30 pounds are about 3 feet long, and they nurse with their mother for at least six months before going off on their own.

Pacific white-sided dolphins are gregarious and often found in large groups of tens, hundreds and sometimes even thousands. They are fast, acrobatic and playful, and are one of the species commonly found bow-riding off boats. They have also been observed working together to catch fish. These dolphins are often seen with other cetaceans, including northern right whale dolphins and Risso's dolphins.

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