| Orca | ||||||||||||||
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Orcinus orca | ||||||||||||||
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| Binomial name | ||||||||||||||
| Orcinus orca |
| Table of contents |
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2 Range and distribution 3 Diet 4 Orcas and man 5 See also 6 External links |
Physical characteristics
The animals are distinctively marked, with a black back, white chest and sides and a white patch above and behind the eye. They have a heavy and stocky body and a large dorsal fin. Males can be up to 9.5 metres long (a little over 31 feet) and weigh as much as 10 tons; females are smaller, reaching 8.5 metres (about 28 feet) at most and a weight of 7 or 8 tons. Calves at birth weight about 180 kilos and are about 2.4 metres long (about 8 feet). At about 1.8m (about 6 feet), the dorsal fin of the male is taller than the female's, and more upright. From a distance, females and juveniles can be confused with various dolphin and porpoise species.
Range and distribution
Most live in the polar regions but they are found in all seas including the Mediterranean and Arabian Sea. At sea they are usually seen in pods of 5-25 animals, although groups of up to 150 have been seen together.
Diet
An Orca's diet depends entirely on availability, although pods can specialize and thus ignore potential prey. It is believed they require around 60kg of food daily. Their prey includes twenty species of cetaceans, five species of pinniped (sealss), thirty species of fish (particularly salmon), seven species of bird and two species of squid, in addition to a variety of other sea creatures, occasionally including larger whales such as Fin Whales, Minke Whales, Gray Whales, or even young Blue Whales. Orcas even hunt and kill Great White Sharks for their nutrient-rich livers and to eliminate competitors for food. It is from their attacks on whales that they gained their name; they do not attack humans.
Orcas and man
Orca are considered to be too small for commercial whaling, but they are sometimes killed because they compete with humans for fish. In the 1950s the U.S. Air Force, at the request of the Icelandic government used bombers and riflemen to slaughter orcas in Icelandic waters. The operation was considered a great success at the time.
In recent years, the Orca's intelligence, trainability, and striking appearance have made it a popular public aquarium or zoo attraction. This, combined with the fact that the animal is not aggressive towards humans, has lead to the image of the species being rehabilitated from an object of fear like Great White Sharks to a respected predator, worthy of toleration, like the wolf in the United States. Orcas in captivity may develop pathologies such as dorsal fin collapse, seen in 60-90% of captive males.
The movie Free Willy (1993) focused on the quest for freedom for a captive orca and his human well-wishers. The whale starring in the movie, Keiko, was originally caught in Icelandic waters. After rehabilitation at the Oregon Coast Aquarium in Newport, Oregon, he was later returned to the waters of the Nordic countries, his native habitat, but continued to be dependent on humans until his death in December 2003.