Pacific White-Sided Dolphin
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.
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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.
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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.