Dall's Porpoise(Phocoenoides dalli)
Dall's porpoise is a porpoise species that is found in the North Pacific. Porpoises are similar to oceanic dolphins, although they have a few differences. They tend to have shorter beaks and spade-shaped teeth that are flattened and different than a dolphin's conical teeth.
When you're out on one of our whale and dolphin watching cruises off the coast of California, keep your eyes open to spot these lovely creatures, the largest of the porpoise species. They occur as far south as Baja California, although they tend to prefer cold waters and are typically found offshore. They are usually found within about 10 meters of the surface, but they have been found to dive up to 94 meters.
Dall's porpoises grow up to 7.5 feet, so they are often smaller than their dolphin cousins. They can weigh up to around 500 pounds. Like many marine mammals, they exhibit sexual dimorphism. The males are larger and have a dorsal fin that is more angled than those belonging to females of the species. Males also grow faster than females.
When you see Dall's porpoises, they are relatively easy to identify. They have a wide body and a small head, and they have no true beak. While these animals are usually black, with white or grey patches around their flanks or bellies, their color patterns can be rather variable. There are two major color patterns, with one type, the truei-type, which is found only in the western part of the Pacific Ocean having a white belly patch that goes further up the body. You aren't likely to see this member of the species while out on our boats. Instead, we typically see the dalli-type. The calves tend to be grey, with no lighter markings on their flippers or flukes.
Members of the Dall's porpoise species tend to be opportunistic hunters. They will eat a variety of different prey animals, including fish and squid. They do not usually eat crustaceans such as shrimp, but they have been found to on occasion.
Unlike many dolphins, Dall's porpoises tend to live in smaller groups, usually of about 2 to 10 members. Groups of hundreds have been noted, however. While they are prey for transient groups of killer whales, some Dall's porpoises have been found swimming and interacting with killer whale populations, even playing with their young.