Steller sea lion
| Steller sea lion | ||||||||||||
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Steller sea lions |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Eumetopias | ||||||||||||
| Gill , 1866 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Eumetopias jubatus | ||||||||||||
| ( Schreber , 1776) |
The Steller sea lion ( Eumetopias jubatus ) is the largest representative of the ear seals . Its colonies are found on the coasts of the northern Pacific . It is named after the German doctor and naturalist Georg Wilhelm Steller .
features
Steller sea lions are yellow-brown in color. As with all ear seals, there is a marked difference in size between males and females. The bulls reach lengths of over 3 m and a weight of 1100 kg. The cows are 240 cm long and weigh a maximum of 300 kg. Bulls are also characterized by a strong mane on their muscular neck.
distribution
There are 51 colonies of Steller sea lions along the Asian and North American Pacific coasts. The largest are in the Aleutian and Kuril Islands . Other important colonies can be found on the coasts of Sakhalin and Kamchatka, as well as Alaska and British Columbia . Further south the sea lions become rarer and the colonies much smaller; the southernmost is on the California Channel Islands .
Way of life
Most of the colonies are on islands in particularly rich fishing grounds. The Steller sea lion dives up to 180 m deep and feeds almost exclusively on fish, but is also said to attack and kill ringed seals and sea otters occasionally . The sea lions often dive in large groups in order to circle the schools of fish together.
Like other sea lions, the bulls arrive in the colonies before the cows. They look for places along the coast, which they defend in fierce battles against their peers. These fights often result in serious injuries. As a result, weaker and younger males are gradually pushed to the edge of the colony, where they have little chance of establishing a harem. As soon as the cows come ashore, the place where they go ashore decides which harem they will belong to. Shortly after going ashore, the females throw their young. A few days later the bull mates with the cows.
Inventory development
Until the 1960s the population was stable at around 250,000 animals. In the following 20 years the population collapsed by 80%. In 1990 the species was placed under the protection of the Endangered Species Act in the United States as threatened , and in 1997 it was upgraded to endangered . As a result, all hunting was prohibited and fishing techniques were changed so that sea lions no longer accidentally get caught in nets. Since then, the eastern population has recovered, with a geographic focus on the Aleutian Islands , but the western population has only stabilized. Due to the age distribution, it is feared that the population in the west will collapse again from 2010 onwards. The reasons are being researched at great expense, but in Alaska, which is dominated by fishing , there is strong political pressure to look for alternative explanations to the predominantly assumed food competition with the fishing industry.
The IUCN lists the Steller sea lions on the Red List of Endangered Species as low endangered.
Others
Because of its high level of aggressiveness, this species is almost never kept in zoos , unlike the Californian sea lion , for example . The Steller sea lion was never hunted on a large scale, except by Eskimos , who used and used its skin to make leather .
literature
- Ronald M. Nowak: Walker's Mammals of the World . Johns Hopkins University Press, 1999, ISBN 0-8018-5789-9 .
Web links
- Eumetopias jubatus in the endangered Red List species the IUCN 2006. Posted by: Seal Specialist Group, 1996. Retrieved on 9 May, 2006.
- Video: Eumetopias jubata (Otariidae) - behaviors in the colony . Institute for Scientific Film (IWF) 1978, made available by the Technical Information Library (TIB), doi : 10.3203 / IWF / E-1498 .
Individual evidence
- ^ Science. Vol 320, from April 4, 2008, p. 44 f.
- ↑ Eumetopias jubatus in the endangered Red List species the IUCN 2006. Posted by: Seal Specialist Group, 1996. Retrieved on 9 May, 2006.