Thursday, January 30, 2014

Beluga Whale

Beluga Whale
The beluga or white whale Delphinus Lucas is an Arctic and sub Arctic cetacean. It is one of two members of the family Orthodontia along with the narwhal and the only member of the genus Delphinus. This marine mammal is commonly referred to simply as the melon head beluga or sea canary due to its high-pitched twitter.It is adapted to life in the Arctic so has a number of anatomical and physiological characteristics that differentiate it from other cetaceans. Among st these are its unmistakable all-white color and the absence of a dorsal fin. It possesses a distinctive protuberance at the front of its head which houses an echolocation organ called the melon, which in this species is large and plastic. The beluga’s body size is between that of a dolphin’s and a true whale’s with males growing up to 5.5 m  long and weighing up to 1,600 kg . This whale has a stocky body; it has the greatest percentage of blubber. Its sense of hearing is highly developed and it possesses echolocation, which allows it to move about and find blowholes under sheet ice.Belugas are gregarious and they form groups of up to 10 animals on average although during the summer months they can gather in the hundreds or even thousands in estuaries and shallow coastal areas. They are slow swimmers but they can dive down to 700 m  below the surface. They are opportunistic feeders and their diets vary according to their locations and the season. They mainly eat fish, crustaceans and other deep-sea invertebrates.The majority of belugas live in the arctic and the seas and coasts around North America, Russia and Greenland their worldwide population is thought to number around 150,000 individuals. They are migratory and the majority of groups spend the winter around the arctic ice cap but when the sea ice melts in summer they move to warmer river estuaries and coastal areas. Some populations are sedentary and do not migrate over great distances during the year.The native peoples of North America and Russia have hunted belugas for many centuries. They were also hunted commercially during the 19th century and part of the 20th century. Whale hunting has been under international control since 1973. Currently, only certain Inuit groups are allowed to carry out subsistence hunting of belugas. Other threats include natural predators contamination of rivers, and infectious diseases.From a conservation perspective the beluga was placed on the International Union for Conservation of Natures Red List in 2008 as being near threatened however the sub population from the Cook Inlet in Alaska is considered Critically Endangered and is under the protection of the United States' Endangered Species Act Of seven Canadian beluga populations, the two inhabiting eastern Hudson Bay and Ungava Bay are listed as endangered.Belugas are one of the cetaceans most commonly kept in captivity in aquarium and wildlife parks in North America Europe and Asia they are popular with the public due to their color and expressiveness.


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