Galápagos fur seal
| Galápagos fur seal | |
|---|---|
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| Male, Santiago Island | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Suborder: | Pinnipedia |
| Family: | Otariidae |
| Subfamily: | Arctocephalinae |
| Genus: | Arctocephalus |
| Species: | A. galapagoensis |
| Binomial name | |
| Arctocephalus galapagoensis Heller, 1904 |
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| Galápagos fur seal range | |
The Galápagos fur seal (Arctocephalus galapagoensis) breeds on the Galápagos Islands in the eastern Pacific, west of mainland Ecuador.
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[edit] Description
Galápagos fur seals are the smallest of otariids. They have a grayish brown fur coat. The adult males of the species average 1.5 m (4 ft 11 in) in length and 64 kg (140 lb) in mass. The females average 1.2 m (3 ft 11 in) in length and 28 kg (62 lb) in mass. They spend more time out of the water than almost any other seal. On average, 70% of their time is spent on land. Most seal species spend 50% of their time on land and 50% in the water.
[edit] Range and habitat
The Galápagos fur seal is endemic to the Galápagos Islands; it cannot be found anywhere else in the world. The Galápagos are a chain of islands found approximately 972 km (604 mi) west of Ecuador. The seals live on the rocky shores of the islands which tend to be on the west side of the islands, leaving only to feed. These seals do not migrate and remain near the islands their entire lives, which averages at about 20 years.
The Galapagos fur seal is now no longer only found on the Galapagos Islands; a colony has relocated to northern Peru, according to the Organisation for Research and Conservation of Aquatic Animals.[citation needed]
[edit] Reproduction
Galápagos fur seals live in large colonies on the rocky shores. These colonies are then divided into territories by the female seals during breeding season, which is mid-August to mid-November. Every mother seal claims a territory for herself and breeds her pups there. This seal has a longer nursing period than any other species of seal. Females have been known to nurse up to three-year-old pups, but usually it takes somewhere from one to two years before the pup leaves and lives on its own.[1] Some pups take longer than others to develop because food shortages, which can be caused by El Niño, do not allow the mothers to properly nourish their young. El Niño has a devastating effect on the fur seals of the Galápagos. During El Nino years, food supplies can drop extremely low, causing many seals to die from starvation, because El Niño raises the temperatures of the waters around the Galápagos, causing the seals’ food supply to migrate to cooler waters.
During the nursing years, females will leave for up to four days at a time to forage for food. They then return to rest and feed their pups for just one day and then return to the sea and repeat the process. While the mother is away, the pup must be careful because other female seals are extremely violent against pups that are not their own. Female seals will defend their territories to the death. They do not want to lose their area because they will not be able to breed then. If a pup wanders into another female’s territory, the female sees this as a threat and will attack or may even kill the pup.
[edit] Feeding and predation
The Galápagos fur seal feeds primarily on fish and cephalopods. They feed relatively close to shore and near the surface, but have been seen at depths of 169 m (554 ft). They primarily feed at night because their prey is much easier to catch then.[2] During normal years, food is relatively plentiful. However, during an El Niño year, there can be fierce competition for food, and many young pups die during these years. The adult seals feed themselves before their young and during particularly rough El Niño years, most of the young seal populations will die.
The Galápagos fur seal has virtually no constant predators. Occasionally, sharks and orcas have been seen feeding on the seals, but this is very rare. Sharks and orcas are the main predator of most other seal species, but their migration paths do not usually pass the Galápagos.
[edit] Conservation
Galápagos fur seals have had a declining population since the 19th century. Thousands of these seals were killed for their fur in the 1800s by poachers. Starting in 1959, Ecuador established strict laws to protect these animals. The government of Ecuador declared the Galápagos Islands a national park, and since then no major poaching has occurred. Despite the laws, another tragic blow to their population occurred during the 1982–1983 El Niño weather event. Almost all of the seal pups died, and about 30% of the adult population was wiped out.
The population is relatively stable now and is on the rise. Since 1983, no major calamity has occurred to decrease their population significantly.[citation needed]
[edit] References
- ^ Horning, M. and Trillmich, F. (1997). "Ontogeny of diving behaviour in the Galapagos fur seal". Behaviour 134: 1211–1257.
- ^ Horning, M. and Trillmich, F. (1999). "Lunar Cycles in Diel Prey Migrations Exert a Stronger Effect on the Diving of Juveniles Than Adult Galapagos Fur Seals". Proceedings of the Royal Society London B 266: 1127–1132.
- MarineBio.(1999). Retrieved September 22, 2008, from http://marinebio.org/species.asp?id=293
- Seal Conservation Society.(n.d.). Retrieved September 22, 2008, from http://www.pinnipeds.org/species/galfursl.htm
- Randall R. Reeves, Brent S. Stewart, Phillip J. Clapham and James A. Powell (2002). National Audubon Society Guide to Marine Mammals of the World. Alfred A. Knopf, Inc. ISBN 0375411410.
