These dolphins keep close company. White-sided dolphins swim in herds of thousands. Members form a close-knit group and will often care for a sick or injured dolphin.
Animals that live in such big social groups develop ways to keep in touch—each dolphin identifies itself by a unique name-whistle. Staying close helps, too. Young dolphins communicate with a touch of a flipper as they swim beside adults.
This species is no longer commercially hunted in the United States. Some are taken for food in Japan's coastal fishery. They are difficult to catch, however, and the numbers taken are not a threat to the total population in Japanese waters. A few have been captured for display in aquariums, and unknown numbers have been accidentally killed in drift and gill nets. Population figures are unknown.
Pacific dolphins swim in formation with other dolphins and sea lions, sometimes leaping from the water in spirited somersaults.