Pygmy right whale
| Pygmy Right Whale | |
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| Family: | Neobalaenidae Miller, 1923
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| Genus: | Caperea Gray, 1864
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| Species: | C. marginata
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| Binomial name | |
| Caperea marginata | |
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| Pygmy Right Whale | |
The Pygmy Right Whale (Caperea marginata) is a baleen whale and as such is a marine mammal of the order Cetacea. The whale, which lives in the Southern Hemisphere, was first described by Gray in 1846, and is the sole member of the genus Caperea and the family Neobalaenidae. Despite its name, the Pygmy Right Whale has more in common with the Gray Whale and rorquals than the Bowhead and Right Whales.
Physical description
The Pygmy Right Whale is rarely encountered and consequently little studied. However it is known that the Pygmy Right is by far smallest of the baleens. The birth weight and size of the animal are unknown. The estimated length of an adult is between 4 and 6.5 m. The estimated weight of an adult is between 3,000 and 3,500 kg. Gestation and lactation periods and longevity are all unknown. Part of the reason for the paucity of data may be the relative inactivity of the whale, making study difficult. The blow is small and indistinct and the whale is usually a slow undulating swimmer, but capable of bursts of acceleration.
The colouring and shape of the Pygmy Right Whale, a dark grey top side and lighter grey underside, commonly with a pair of chevron-shaped lighter patches behind the eyes, is similar to that of the Dwarf and Antarctic Minke Whales and at sea may easily be confused with these two species if the jaw and flippers are not. The arched jawline is not as pronounced as other Right Whales and may not be sufficient to distinguish a Pygmy Right from a Minke. The long, narrow cream-coloured baleen plates with a distinctive white gumline are the most effective discriminators. Unlike true Right Whales, Pygmy Rights do not have callosities. The dorsal fin is falcate (crescent-shaped) and located about three-quarters of the way along the back of the animal. Unlike the Minke Whale, occasionally the dorsal will not be seen on the whale surfacing, and the tail fin has not been observed clear of the water.
Analysis of the stomach contents of dead Pymgy Rights indicates that it feeds on copepods and euphausiids. It is not known if the animal feeds close to shore or at sea. Similarly the social and mating structures are unknown. The whale is typically seen alone or in a pair, with occasional sightings of groups up to 10 strong and one report of 80 animals grouped closely in oceanic waters.
Population and distribution
The Pygmy Right Whale is perhaps the least studied of all cetaceans on account of its sparse population (as of 1998 fewer than 20 encounters in the open sea have been recorded worldwide - the whale prefers sheltered shallow bays). The species lives in the Southern Hemisphere and is believed to be circumpolar, living in a band from about 30°S to 50°S in areas with surface water temperature between 5 and 20 degrees Celsius. One individual was found washed up as far south as Tierra del Fuego (55°S) in southern Argentina. Individuals have been found on the coast of Namibia, South Africa, Australia and New Zealand. One group may be a year-round resident off Tasmania. The total population is unknown.
Whaling and whale-watching
On account of its relatively small size and sparse distribution the Pygmy Right Whale was not the target of a whalers. It is likely that a few Pygmy Rights were taken opportunistically by whalers hunting Minke Whales. Also a few Pygmy Rights are known to have been caught in fishing nets. However these factors are not believed to have had a significant on population.
Most data about Pygmy Right Whales comes from individuals washed up on coastlines; they are rarely encountered at sea and so they are not the primary subject of any whale watching cruises.
References
- Template:IUCN2006 Database entry includes justification for why this species is of least concern
- Encyclopedia of Marine Mammals, Perrin Wursig and Thewissen (eds). ISBN 0-12-551340-2
- Whales Dolphins and Porpoises, Mark Carwardine. ISBN 0-7513-2781-6
- National Audubon Society Guide to Marine Mammals of the World. ISBN 0-375-41141-0
- Pictures of Pygmy Right Whales are rare. One picture is available at Cetacea.org's Pygmy Right page.