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Dall's Porpoise

While traveling the sea-lanes of the Inside Passage, you may see what look like small killer whales riding the waves of your vessel. Upon closer inspection, if you get the chance, you will see that they are Dall's porpoises, one of the fastest cetaceans in the world.

Dall's porpoises belong to the order Cetacea, a large order of whales, dolphins, and porpoises. The Dall's porpoise is a fast and powerful swimmer and has been clocked at 30 knots. Dall's porpoises are extremely stocky with small, pointed flippers, a small, almost triangular, white-tipped dorsal fin, and a very small head. The body is black with a prominent white patch on the flanks and belly that extends from about mid-body almost to the tail. The Dall's porpoise reaches a maximum body length of about 7 feet and weighs up to 350 pounds.

Dall's porpoises are intense and restless animals, not prone to jump and play like many of their dolphin cousins. When swimming, they rush to the surface, sending a "rooster tail" of spray into the air, a feature by which they may be easily identified. Dall's seem to enjoy riding the bow or stern waves of boats and may stay with a boat for half an hour or more.

Dall's porpoises have a high metabolism and must spend most of their time hunting. They feed on squid, crustaceans, and several kinds of fish. A Dall's porpoise eats twice as much as a bottlenose dolphin of the same weight. Dall's have very thin blubber and large hearts. Their large hearts and high metabolism may serve to keep them warm in the cold waters of the North Pacific, as well as to allow their speedy swimming.

There are no Dall's porpoises in captivity. All those captured have died quickly, with only one, named Marty, surviving for a year. Marty was responsive to training, but was said to be nervous and unable to calm down.

Dall's porpoises usually travel in groups of ten to twenty, but gatherings of at least 200 have been reported. Unlike other cetaceans, Dall's porpoises produce repeated bursts of clicking sounds, but no whistles. The Dall's also emit unique high-frequency sounds that help them navigate and find food. Like sonar, the porpoise's sounds bounce off objects in its path. By listening to the returning echoes of the sounds, the porpoise can determine the distance to the object.

Dall's porpoises are fascinating marine mammals that are fun to watch. While you're traveling the waters of the Inside Passage, be sure to watch the waves of your vessel for this purposeful porpoise.

The National Marine Fisheries Service provides regulations for safe and considerate viewing.