Mammals - Sea Lions - Galápagos

By Karey Fuhs

The endemic Galapagos Sea Lion (Zalophus californianus wollebacki, lobo marino) is found all throughout the islands and is absolutely fearless of humans. You will definitely have the chance to watch some of the 50,000 inquisitive juvenile sea lions, playful adult sea lions, protective mother sea lions and competitive male sea lions found in the archipelago from both land (some resting on dinghies and landing points) and sea vantage points.

Males, or bulls, can be distinguished from the females, or cows, by their thick necks, bumped foreheads, and immense size (full-grown males can weigh up to 250 kg). They jealously guard and protect their territory, a finite area covering land and water space, a harem of approximately 20 cows and any number of pups. When bulls lose land battles to other, more aggressive dominant males, they conglomerate in specific island sites, or bachelor pads, to heal and rest until the next challenge.

The mating season varies from island to island, but it generally occurs from June to November. Females give birth to four or five pups over their lifetimes, one every two years. Copulation usually takes place in the water four weeks after a birth, but due to “delayed implantation,” the egg is not implanted into the womb for another two months. Gestation takes another nine months, thus finalizing the annual birth cycle.

Nine out of ten sea lion pups are females and one-tenth males, and all stay together in “kindergartens,” swimming and playing in the shallow water. After five months, the pups can start fishing for themselves, although they still depend on their mothers; after three years, cows have reached sexual maturity and begin to reproduce; and after five years, the slow-blooming males reach their adulthood. Most sea lions live for fourteen or fifteen years.

Sea lions feed mostly on sardines (the cause of their bad breath), for which they may travel ten to fifteen kilometers out from the coast over the span of days to hunt. It is in deep water that sea lions encounter and must defend themselves from their only predators, sharks.

Sea lions are common on most islands (even the populated ones). You can see surfing sea lions at Punta Suarez (Española) and North Seymour, and you can see one of the bulls’ bachelor pads at South Plaza.

The Galapagos fur seal (Arctocephalus galapagoensis, lobo de dos pelos) should technically be called the Galapagos fur sea lion, since it not a true seal. The fur seal is easily distinguished from the sea lion by its smaller size, darker color, shorter snout, and bear-like facial appearance (hence its scientific name, arcto = bear; cephalus = head). It also has a much thicker, denser coat consisting of two distinct layers: on outer coat of long hairs and an inner coat of short, dense fur. Finally, since thick-coated fur seals are less tolerant of the heat than sea lions, they are most often found in shady coves and rock crevices with adjacent deep-water areas.

The mating season is from August to November, followed by delayed implantation and fertilization in the next few months and birth the following year. Fur seal cows generally give birth less frequently than sea lions, about once every three years.

Fur seals mainly feed on fish and squid, which they hunt in depths of up to 100 meters during the night hours in order to escape sharks. Unfortunately, fur seals had a more destructive predator, which caused populations to drop to near-extinction in the nineteenth century: humans. The fur seals have made a remarkable comeback since then, and it is predicted that over 25,000 now habituate the archipelago. Although they are fairly abundant, they are not often seen, due to their choice of habitat. Your best bets are the western archipelago(Fernandina and Isabela) Puerto Egas (Santiago) and Rabida.