Zalophus
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California sea lion ( Zalophus californianus ) |
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| Scientific name | ||||||||||||
| Zalophus | ||||||||||||
| Gill , 1866 |
Zalophus is a genus of ear seals (Otariidae). It comprises the following three types :
- California sea lion ( Zalophus californianus )
- Japanese sea lion ( Zalophus japonicus , extinct)
- Galápagos sea lion ( Zalophus wollebaeki )
The division into three types instead of the previously common grouping into one type was controversial.
features
The seals of the genus Zalophus reach a head body length of 150 to 250 centimeters and a weight of 50 to 400 kilograms. As with all ear seals, the males are significantly larger and heavier than the females. The males are dark brown in color, the females are lighter. In contrast to the other ear seals, the males do not have a clearly defined mane.
Distribution and way of life
These seals live in the Pacific . The California sea lion has its colonies on the coast of the south-western USA and northern Mexico , the Galápagos sea lion on the Galápagos Islands . The extinct Japanese sea lion lived in Japan and Korea .
These seals go to the coasts to rest. When looking for food, they dive up to 40 meters deep and prey on fish and octopus . During the breeding season, the males establish strictly guarded territories on the coasts and try to gain a harem from several females.
Systematics
Traditionally, the three populations were listed as subspecies of a common species, but this was controversial. Wilson & Reeder classified the three populations as separate species. A molecular genetic study by Wolf et al. (2007) came to the same conclusion. As a result, the mitochondrial and cell nucleus SNPs justify separation into several species. According to the molecular clock , the Californian and Galápagos sea lions separated around 2.3 (± 0.5) million years ago.
literature
- Ronald M. Nowak: Walker's Mammals of the World . 6th edition. Johns Hopkins University Press, Baltimore 1999, ISBN 0-8018-5789-9 (English).
- Don E. Wilson, DeeAnn M. Reeder (Eds.): Mammal Species of the World . A Taxonomic and Geographic Reference . 3. Edition. Johns Hopkins University Press, Baltimore 2005, ISBN 0-8018-8221-4 (English).
- JBW Wolf, Diethard Tautz, Fritz Trillmich: Galapagos and Californian sea lions are separate species. Genetic analysis of the genus Zalophus and its implications for conservation management . In: Frontiers in Zoology . tape 4 , no. 20 , 2007, doi : 10.1186 / 1742-9994-4-20 .
