Marine Mammals

Whales, Dolphins, Seals, and Sealions

Information taken from “Vertebrates of Torrey Pines Reserve” by D. Hunsaker

There are several species of marine mammals which can be observed in the coastal area and out to sea. Triangular fins above the surface do not always mean a shark, so keep a close eye for groups of porpoises and whales which have distinctive dorsal fins. Since the porpoises and whales are air-breathing mammals, they periodically come to the surface to inhale and exhale. In the process, a portion of the back, including the blow hole and dorsal fin are exposed above the surface of the water, and this approach to the surface, and rolling dive in which the back is exposed, is indicative of porpoises. They usually travel in small groups, which also serves to distinguish them from sharks.

The porpoises and whales which occur off the coast include the Pacific Bottlenose Porpoise (Tursiops gillii), the Dall Porpoise (Phocoenoides dalli), the Pacific White-sided Porpoise (Lagerhynchus obliquidens), the Pacific Dolphin (Delphinus bairdii), the Pilot Whale (Globicephala scammonii), the Fork-striped Porpoise (Stenella caeruleoalba) and the Killer Whale (Orcinus orca). Two sperm whales can be occasionally observed, the Pygmy Sperm Whale (Kogia breviceps) and the Sperm Whale (Physeter catodon). The Arch-beaked Whale (Mesplodon carlhubbsi) and the Goose-beaked Whale (Ziphius cavirostris) have also been reported off the coast.

The most popularly known whale is the Gray Whale (Eschrichtius gibbosus), which migrates to the lagoons of Baja California for breeding and birth. The migration begins in late fall when the whales traveling singly or in small groups can be seen off the coast adjacent to the Reserve, traveling at slow speeds. When they arrive at the large shallow lagoons of Baja California the females give birth to their young, nurse them, and rest in anticipation of the return to the north. Breeding takes place before the migration back to the Alaskan waters begins. January finds the whales moving back north again accompanied by the small babies which swim with the mothers.

The other marine mammals which can be expected to occur in the waters of the Reserve are the Seals and Sealions; the Harbor Seal (Phoca vitulina) and the California Sealion (Zalophus californianus). The Harbor Seal reaches a length of about 6 feet and weighs less than 300 pounds. It can be identified by the grayish-yellow blotches which form a mottled pattern over a darker ground color. There are no external ears. The hind flippers always are extended directly out from the body, they cannot be brought forward, as they can in sealions.

The California Sealion is considerably larger than the Harbor Seal, with the males reaching a maximum of 8 feet and weighing close to 1000 pounds with the female growing to 6 feet and 300 pounds. Sealions can use their hind flippers in locomotion so they are often seen sunning themselves on rocks several feet above sea level, and the Harbor Seals are usually much closer to the sea. The sealions breed on the Channel Islands from May until August and the Harbor Seal mates in September. Pups are born about a year later.

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