Phocoenoides

Phocoenoides is a genus of porpoises, family Phocoenidae, order Artiodactyla, containing a single living species, Dall's porpoise, Phocoenoides dalli, named for the American naturalist William Healey Dall and endemic to the North Pacific Ocean. It is the largest porpoise species and the sole member of its genus, occurring from California to the Bering Sea and Okhotsk Sea in the east and down to the Sea of Japan in the west, preferring cold water below 18 degrees Celsius in offshore regions and deeper coastal waters near submarine canyons and fjords. Two subspecies are recognized, dalli and truei, distinguished by coloration rather than treated as separate species. Dall's porpoises have a wide, robust body with a small head and no prominent beak, a triangular mid-body dorsal fin, and predominantly black coloring with white-to-grey patches on the flanks and belly; they grow up to 2.3 meters and 130 to 220 kilograms, and their rapid surface swimming produces a distinctive spray called a rooster tail.