The Galápagos fur seal, Arctocephalus galapagoensis (Heller, 1904), has a gray-brown dorsal body surface and lighter brown ventral surface. Adult males measure up to 1.5 m long and weigh 64 kg on average. Adult females are smaller, measuring an average of 1.2 m in length and weighing from 22-34 kg (average 28 kg).

Southern fur seals (Antarctic, Galapagos, Guadalupe, Juan Fernandez, New Zealand, South African/Australian, South American, and Subantarctic fur seals) are the most land loving seals of the Family Otariidae spending only about 70% of their life in the water. Nevertheless, they are still deep divers; females have been observed diving to a maximum depth of 169 m for 6.5 minutes. On average, females dive for about 16.4 hours to depths of no more than 30 m at night when foraging for food. Nowak (1999) states that "foraging trips have been found to last 50-70 hours at the time of the new moon but only 10-20 hours at the time of the full moon." During the warm months, females spend 4-6 days in the water foraging for food and 1 day on land. Adult males are very territorial defending territories that can extend 200 sq m. They will not abandon their territories to eat until all of their stored energy has been depleted. Approximately 30% of males die in territory fights annually. Females also defend territories which are about half the size of male territories. Unlike other seal species that prefer sandy beaches for their terrestrial habitat, the typical territory of a Galápagos fur seal consists rocky areas with shade for cooling. These seals must maintain an internal body temperature of about 37.7°C, so they cool themselves in tide pools, a method of thermoregulation that females teach to their pups to keep them from overheating (Limberger, 1986). These seals also have a smaller body size to release heat quickly, and they can also sweat, depending on their level of hydration. Thermoregulation is also controlled internally by the cardiovascular system by directing blood flow away from the flipper is the seal is too cold, and toward the flippers if the seal is too warm.

The Galápagos fur seal is a member of the Family Otariidae (fur seals and sea lions), which includes 14 species in 7 genera. The distribution of this family is complex. They are found along coasts of North and South America, central and northern Asia, New Zealand, and several other islands, including the Galápagos.

Sea lions, in general, are large, ranging from around 150 kg to over 1,000 kg, and males tend to be much larger than females. Their bodies are slender and elongate. Small, cartilaginous external ears are present. All otariids have fur, however, sea lions have relatively coarse hair and fur seals have dense underfur. Both are generally shades of brown without stripes or other contrasting markings. The fore flippers of otariids have small claws, and are long and paddle-like, measuring more than 1/4 of the length of the body. The surfaces of the fore flippers are leathery. The hind flippers are also large. They differ from those of true seals (phocids) in that they can be rotated under the animal when it is on land to support the body and aid in locomotion. Otariids also have a small but distinct tail.

Otariids tend to be highly social and forming large herds during the breeding season. Depending on their size and strength, individual males maintain harems of 3-40 females. They establish territories on their breeding grounds before females arrive, which they defend aggressively from other males. Females give birth to pups from the previous year's breeding season soon after they arrive, which is followed by mating. A period of delayed implantation insures that the young will be born in a year when the breeding herds are re-established.

World Range & Habitat

The Galápagos fur seal, smallest of the pinnipeds, lives only in the Galápagos Islands. This species does not seem to share territory or food with the other pinniped species in the islands such as the Galápagos sea lion. No current data on population size is available. The most recent estimate of about 40,000 is based on a survey from 1978, and it is thought that the 1982-83 El Niño event significantly reduced the population.

Feeding Behavior (Ecology)

Galápagos fur seals feed on fish and cephalopods (Nowak, 1999; Reidman, 1990), close to shore and exclusively at night when their prey migrates closer to the surface. Sharks and orca are known to be predators but not to any great extent.

Life History

Galápagos fur seals are a polygynous species. They have the longest pupping period of any fur seal (or pinniped). Pups are born between mid-August and mid-November. Pups weigh 3-4.5 kg at birth.

Females reach sexual maturity at 3-4 years, males around 7-10 years of age. The preferred breeding habitat is rocky shores with sea caves on the western coasts of the islands. Females give birth 2-3 days after coming ashore. About one week after giving birth, females begin alternating between foraging for food in the water for 1-4 days and nursing for 1 day. The duration of the nursing periods and the feeding trips appear to vary with the phase of the lunar month�"mothers have been seen to spend 1.5-75 hours (median 22.5 hours) on shore feeding their pup and 3.5-127 hours (median 33.5 hours) feeding at sea. The Galápagos fur seal has the longest nursing period of any seal, the pups finally being weaned between 1-2 years but sometimes even being nursed at the age of 3 years. Only the walrus has a nursing period close to this. The nursing period of a particular pup tends to be longer if food has been scarce during the time of its nursing, and the long period may therefore be a mechanism that the species has evolved to improve survival rates through such events as El Niños.

Observations have shown that the pups spend more time playing and moving around when their mother is away, although they have to take care since females can be quite ferocious towards pups that are not their own.

The female mates about 8 days after giving birth. As with other fur seals the males maintain breeding territories, in this case for about 27 days at a time.

Pups begin to swim a little after a few months and start to engage in some independent feeding at 9-12 months. They molt into their grayish-brown adult fur at about 4 months. Galápagos fur seals do not migrate.

Comments

Thousands of Galápagos fur seals were killed by commercial sealers in the 19th century. They became a protected species under Ecuadorian legislation in the 1930s, however this was not enforced until 1959 when most of the Galápagos Islands were established as a National Park. The waters around the islands are also protected, including a no-fishing zone, to a distance of 40 nautical miles. The species is listed as Vulnerable on the IUCN Red List and as an Appendix II species under CITES.

Because of the geographic position of the Galápagos Islands, El Niño events can significantly reduce food supplies causing starvation among the seals, which happened during the 1982-1983 El Niño event. Almost all of young fur seals were lost along with about 30% of adult females and non-territorial males and almost 100% of the large territorial males.

These fur seals have also been at risk of mortality due to entanglement in gillnets, but this problem seems to have been solved. Feral dogs have also attacked and killed Galápagos fur seals, however this problem is now controlled by the Galápagos National Park Service.

The Blue-footed Booby (Sula nebouxii excisa, piquero de patas azules) is most easily identified, as its name suggests, by its bright blue feet. It has brown upper plumage and white lower plumage, with wings being a slightly darker brown than the rest of the body. Juveniles are completely brown and receive their coloration after about one year.

Males are slightly smaller than females and perform an elaborate, intensely entertaining mating dance to attract their female partner. The male begins by lifting up his enormous clown-feet one-by-one, and then stops in a distinctive pose, beak raised skyward, announcing his manhood with a loud whistle, pointing out his tail, and opening his wings. This is accompanied by a love-offering of sticks and twigs. Females join in the mating dance, following the same movements, but respond with a guttural honk. Besides their distinguishing sounds, the females also have larger eye pupils.

Breeding can take place at any time of the year when the food supply is abundant. Up to three eggs are laid in a “guano ring,” or nested circle of booby dung. When food is scarce, the oldest sibling will push younger sibling(s) out of the guano ring in an act of “cainism.” This form of natural selection is effective, because young outside of the ring are refused care and ultimately perish.

The young take two to six years to mature, at which time they will return to their island birthplace to mate. Meanwhile, they travel among the islands feeding on fish, which are caught in a graceful plunge dive. Watching the boobies fish�"either from the air or underwater�"is a major highlight in the Galapagos.

Blue-footed boobies are best viewed in coastal waters at the visitor sites of Punta Suarez (Española), North Seymour, and Punta Pitt (San Cristóbal).

The Swallow-tailed Gull (Creagrus furcatus) is an equatorial seabird in the gull family Laridae. The species is endemic to the Galápagos Islands. When it is not breeding it is totally pelagic (flying and hunting over the open oceans), migrating eastward to the coasts of Ecuador and Peru. A notable aspect of the swallow-tailed gulls are the fleshy red rims around the eyes; it is speculated that these may aid its noctural vision.

It is unique within the gulls for feeding exclusively at night (Harris 1970), feeding mostly on squid. It breeds colonially throughout the year; unlike most other gull species it lays a single egg per breeding attempt (Agreda & Anderson 2003) .

A type of fish that glows can be seen from above the water, making it easy for the Swallow-tailed Gull to see and attack it at night.

The Great Frigate Bird resembles a huge blackbird that hovers lazily in the sky. Frigate birds belong to the family Fregatidae, which contains five species world-wide. In the Galapagos there are two species: the Great Frigate bird and the Magnificent Frigate bird. Of the two, the Great Frigate bird has the greater world-wide distribution, being found primarily throughout the tropical Pacific and Indian Oceans.

The Magnificent Frigate bird is found in the Caribbean and on the Pacific and Atlantic coasts of the Americas. The Galapagos population of Magnificent Frigate birds is considered to be an endemic subspecies.

In the Galapagos, the two species can be seen nesting side by side, but when Frigate birds are sighted in the air, they typically are Magnificent Frigate birds, as Great Frigate birds tend to forage much further out at sea. As with the three similar species of Booby birds, similar species of Frigate Birds avoid competition by feeding in different locations.

You can tell the two species of Frigate birds apart by their sounds - a Great Frigate bird makes a 'gobbling' noise like a turkey, while a Magnificent Frigate bird will make a rattling or drumming sound.

Great Frigate birds are large, with iridescent black feathers (the females have a white underbelly), with long wings (male wingspan can reach 2.3 metres) and deeply-forked tails.

The males have inflatable red-coloured throat pouches, which they inflate to attract females during the mating season.

Both species of Frigate bird have extremely high wingspans to bodyweight ratios allowing them soar and to fly extremely well and with excellent control. Using this control, Frigate birds routinely steal food from other birds by grabbing them by their tail feathers and shaking them until they regurgitate their food.

However, Frigate birds are also capable of capturing their own prey. Since Frigate birds have only a small oil gland and very little waterproofing in their wings, Frigate birds cannot dive and must instead rely on their superb aerobatics to snatch flying fish out of the air.

Frigate birds do not swim and cannot walk well, and cannot take off from a flat surface. Having the largest wingspan to body weight ratio of any bird, they are essentially aerial, able to stay aloft for more than a week, landing only to roost or breed on trees or cliffs.

To attract females, male Frigate birds will blow up their bright red throat pouch and skwalk loudly as females pass overhead. The females will then choose a suitable male and land next to him. The male responds by spreading his huge wings around the female to protect her from other males.

After mating has taken place, a single egg is then laid, and although the baby Frigate bird can fly after about five months, it stays with its parents and is dependent on them for about a year. Because of this long investment in each chick, Frigate birds can only mate once every other year.

It is typical to see juveniles as big as their parents waiting to be fed. When they sit waiting for endless hours in the hot sun, they assume an energy-efficient posture in which their head hangs down, and they sit so still that they seem dead. But when the parent returns, they will wake up, bob their head, and scream until the parent opens its mouth. The starving juvenile plunges its head down the parent's throat and feeds at last.

Female Magnificent Frigate birds are black, but have a white breast and lower neck sides and a brown band on the wings. Female magnificent fingerboards have a blue eye ring. Young birds have a white head and white under parts.

Frigate birds feed mainly on fish, and also attacks other seabirds to force them to disgorge their meal. Frigate birds never land on water, and always take their food items in flight.

North Seymour is a small island near to Baltra Island in the Galapagos Islands. It was formed by uplift of a submarine lava formation. The whole island is covered with low, bushy vegetation.

The island is named after an English nobleman, Lord Hugh Seymour. It has an area of 1.9 km² and a maximum altitude of 28 metres. This island is home to a large population of blue-footed boobies and swallow-tailed gulls. It hosts one of the largest populations of frigate birds.

North Seymour has a visitor trail approximately 2 km in length crossing the inland of the island and exploring the rocky coast.

The stock for the captive breeding program of the Galapagos Land Iguana is descended from iguanas which William Randolph Hearst translocated from Baltra Island to North Seymour Island in the 1930s.