Sperm whales
| Sperm whales | ||||||||||||
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Sperm whale ( Physeter macrocephalus ), mother with calf |
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| Physeteridae | ||||||||||||
| JE Gray , 1821 |
The sperm whales (Physeteridae) are a family of toothed whales . In addition to the actual sperm whale , it includes (according to some views) the two species of the dwarf sperm whale .
features
Sperm whales differ significantly in size. While the actual sperm whale can reach 20 meters in length and 50 tons in weight, the dwarf sperm whales are only up to 3.4 meters long and weigh 400 kilograms. What they have in common is the excessively large forehead with the spermaceti organ. Teeth are only present on the lower jaw, the unpaired nostril is on the left side of the skull - in the case of the dwarf sperm whale on the vertex and in the case of the actual sperm whale on the front head.
Systematics
Traditionally, the sperm whales are classified as toothed whales. However, some phylogenetic analyzes see them as a sister group of the baleen whales and therefore more closely related to them than to the other toothed whales. But this is controversial. The family of the sperm whales is placed in a superfamily Physeteroidea with some extinct whales from the trunk line of the sperm whales (e.g. Livyatan melvillei ) .
Within the sperm whale, two genera with three species are distinguished:
- Genus Physeter
- Sperm whale ( Physeter macrocephalus )
- Genus pygmy sperm whales ( Kogia )
- Small sperm whale ( Kogia simus )
- Pygmy sperm whale ( Kogia breviceps )
Due to large differences in size, body structure and way of life, the minke sperm whales are sometimes classified in a separate family, Kogiidae .
literature
- Ronald M. Nowak: Walker's Mammals of the World . Johns Hopkins University Press, 1999 ISBN 0-8018-5789-9
- Milan climate: cetacea, cetaceans. In: Wilfried Westheide , Reinhard Rieger (Ed.): Special Zoology. Part 2: vertebrates or skulls. Spektrum Akademischer Verlag, Heidelberg / Berlin 2004, ISBN 3-8274-0307-3 , especially pp. 640–641.
