Pygmy sperm whale
| Pygmy sperm whale | ||||||||||||
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Little Sperm Whale ( Kogia breviceps ) |
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| Scientific name | ||||||||||||
| Kogia breviceps | ||||||||||||
| ( Blainville , 1838) |
The dwarf sperm whale ( Kogia breviceps ) is a species of whale from the family of the dwarf sperm whale (Kogiidae). Its closest relative is the little sperm whale .
description
Minke sperm whales reach a length of up to 3.3 meters and a weight of up to 400 kilograms; they are thus somewhat larger than the small sperm whales. In addition, they can be distinguished from these by the smaller fins .
The head makes up a maximum of 15 percent of the body length, the snout region is large and slightly arched, on top of which, like the other sperm whales, lies the whale organ . While the snout of young animals is still relatively pointed in profile, it becomes increasingly angular to rectangular in adult animals. The narrow mouth is below. In the lower jaw, they have between 20 and 32 curved and very sharp teeth, while the upper jaw is toothless.
Their skin is colored blue-gray on the top, while the underside is lighter, almost pink in color. As with all sperm whales, the blowhole is shifted to the left. A light stripe runs on each side from the eyes to the short, wide flippers , which are convexly curved. The broad parts of the river taper towards the end.
distribution
Minke sperm whales live in tropical and temperate oceans around the world. They mainly live in deep waters and rarely come near the coast. They may migrate to cooler seas in the summer months to return to the tropics in winter. There are sightings or strandings , for example, in the Atlantic (with Ireland or Nova Scotia as the northernmost points), in the Indian Ocean and in the Pacific (north up to the height of Japan or southern Canada ).
Most of the information about the distribution of the pygmy sperm whale comes from finds of stranded specimens. Especially on the southeastern coast of the United States, this species is the second highest number of stranded animals, and they are also found frequently off the coast of South Africa.
Way of life
Since pygmy sperm whales are seldom seen in the sea and most of the knowledge comes from researching stranded animals, relatively little is known about their way of life. They move unobtrusively and come to the surface of the water without splashing or blowing much . Sometimes you can see them floating motionless in the water. Their submersion is similarly unspectacular: they simply disappear into the water.
These whales either live alone or in small groups of three to six animals, and their diet consists primarily of squid and crustaceans . Presumably they are excellent divers, catching their food at depths of 200 to 1200 meters.
Reproduction and development
Very little is known about the breeding of the pygmy sperm whale. Due to stranded animals, it is assumed that sexual maturity is reached with a body length of 2.7 to 2.8 meters. The gestation period is about eleven months and the young are born with a body length of 1.20 meters. The lactation period is likely to last at least a year, but the females can become pregnant again during this time.
threat
The world's minke sperm whale population is unknown. Your IUCN status is "insufficient data basis".
Minke sperm whales have never been hunted on a large scale; on a small scale, they are sometimes hunted by whalers from Japan and Indonesia . Other threats are likely to be marine pollution (stranded specimens with plastic bags in their stomachs were found) and the risk of being caught in fishing nets, especially in set nets such as those used off the coast of Sri Lanka.
A dead pygmy sperm whale is pulled into port on La Gomera (Canary Islands).
The (non-fatal) injuries to his skin were caused by a ship's propeller.
Biologists later autopsied him , but could not clarify the cause of death.
A tourist photographs the animal.
Systematics
Together with the small sperm whale , the dwarf sperm whale forms the genus of the dwarf sperm whale ( Kogia ), which, together with the actual sperm whale, was usually united in a common family of sperm whales , although some zoologists place them in their own family Kogiidae . In the past, both small sperm whales were thought to be a single species, and it was only in 1966 that it was recognized that they were two different species.
literature
- Mark Carwardine: Whales and Dolphins in European Waters. Delius Klasing, Bielefeld 2003, ISBN 3-7688-1456-4 (high quality guide).
- Ralf Kiefner: Whales & Dolphins worldwide. Jahr, Hamburg 2002, ISBN 3-86132-620-5 (guide of the magazine "diving", very detailed).
- J. Niethammer, F. Krapp (Ed.): Wale und Delphine 1. Aula, Wiesbaden 1994, ISBN 3-89104-559-X ( Handbook of Mammals in Europe. Volume 6, Part 1a; very detailed specialist book).
- Randall R. Reeves, Brent S. Stewart, Phillip J. Clapham, James A. Powell: Sea Mammals of the World. A Complete Guide to Whales, Dolphins, Seals, Sea Lions and Sea Cows. Black, London 2002, ISBN 0-7136-6334-0 (guide with numerous pictures).
- Maurizio Würtz, Nadia Repetto: Underwater World. Dolphins and Whales. White Star, Pittsburg 2003, ISBN 978-88-544-0452-6 (identification book).
Web links
- Kogia breviceps inthe IUCN Red List of Threatened Species 2011.2. Posted by: BL Taylor, R. Baird, J. Barlow, SM Dawson, J. Ford, JG Mead, G. Notarbartolo di Sciara, P. Wade, RL Pitman, 2008. Retrieved April 3, 2012.
Individual evidence
- ↑ WDCS : Species Guide: Pygmy Sperm Whale
- ↑ Kogia breviceps in the IUCN Red List of Threatened Species 2011.2. Posted by: BL Taylor, R. Baird, J. Barlow, SM Dawson, J. Ford, JG Mead, G. Notarbartolo di Sciara, P. Wade, RL Pitman, 2008. Retrieved April 3, 2012.