Dall's porpoise is a species of porpoise endemic to the North Pacific. It is the largest of porpoises and the only member of the genus Phocoenoides. The species is named after American naturalist W. H. Dall.
Dall's porpoise
William Healey Dall's 1873 field notes on Phocoenoides from the Smithsonian Institution's Field Books collection
A Dall's porpoise on a calm day in the Shelikof Strait
A group of Dall's porpoises near Point Reyes
Porpoises are small dolphin-like cetaceans classified under the family Phocoenidae. Although similar in appearance to dolphins, they are more closely related to narwhals and belugas than to the true dolphins. There are eight extant species of porpoise, all among the smallest of the toothed whales. Porpoises are distinguished from dolphins by their flattened, spade-shaped teeth distinct from the conical teeth of dolphins, and lack of a pronounced beak, although some dolphins also lack a pronounced beak. Porpoises, and other cetaceans, belong to the clade Cetartiodactyla with even-toed ungulates.
Porpoise
Harbour porpoise skeleton
"Rooster tail" spray around swimming Dall's porpoises
Harbour porpoise in captivity