Adapted perfectly to its habitat, it has a thick layer of grease as well as a fur which isolates it from the cold, the white color of its peeling ensures an ideal camouflage to him on the ice-barrier and its black skin enables him to better store its body heat. Equipped with a short tail and small ears, the bear has a relatively small tapering head and a long body adapted to swimming.
The polar bear is a semi-watery marine mammal, whose survival depends primarily on the ice-barrier and the marine productivity. It drives out as well on ground as in water.
Cut and weight
The polar bear is - with the bear kodiak - the largest alive terrestrial carnivore. The adult males weigh between 400 and 600 kg and can sometimes reach 800 kg for a size from 2,4 to 3 meters length. The bear presents an important sexual dimorphism: the females are generally twice smaller than the males, weigh from 200 to 300 kg and measure from 1,9 to 2,1 meters. With the birth, the bear cubs weigh only between 600 and 700 grams . The record of weight for an polar bear is currently of 1102 kg.
The polar bears have rather spectacular catches of weight. For example, in Canada, an polar bear female took more than 400 kilos in nine months. In November, it weighed 92 kg, but in August, it was weighed to 505 kg. This is explained by the grease of the seals which are eaten in spring.
Recent data suggest that the weight of the polar bears declines. These data can be taken as an indication of the pressures which weigh on them. A study of 2004 of the National Geographic Society showed that the weight of the polar bears, on average, was 50% lower than their weight in the years 1970 . As an example, in 2007, the females of Hudson Bay had an average weight of only 230 kg, against a weight of 300 kg in the years 1980.
Their weights do not prevent them from being very swift on the dry land. They can without problem exceed a man in race.
The polar bears are excellent swimmers thanks to their layer of grease. They can be seen on the open sea to hundreds of meters of any ground. They swim by using their front legs to be propelled and their back legs like rudder.
Skin and fur
The polar bear is immediately recognizable with its white fur. With the difference of other Arctic mammals (such as the Arctic fox), it never changes this peeling for a color more sunk into summer. The hairs are not really pigmented in white; they not-are pigmented and hollow, like the grey hair at the man.
An interesting characteristic of its fur is that it appears black if it is photographed under ultraviolet rays. Certain people put forth the assumption that the hairs dig drains collecting the light towards the black skin of the bear to help it to remain with the heat during the cold winters and without sun, but that is contradicted by more recent studies. Measurements show that the hairs strongly absorb the purple and ultraviolet rays. This is why the skin of the polar bear seems often yellow.
The polar bears renew their furs from May to August. The fur is usually of 5-15 centimetres on the major part of the body. However, on the forefeet, the males have hairs longer and growing in length until 14 years lâge. One supposes that is a form of attraction for females, with the manner of the mane of the lion.
These bears are extremely well isolated; so much so that they catch hot with higher temperatures with 10 °C. So they were prélassent sometimes on the ice to cool; and on ground, they can dig with the research of the colder layer of permafrost under the ground.
Geographical distribution and habitat
The polar bear is a species living on the level of the north pole, at the edge of the Arctic Ocean, whose habitat is limited almost to the ice-barrier. The southernmost point of their habitat is in the James bay at Canada. Although manpower decrease in the north of 88° of latitude, one can meet some in all Arctic.
The most populations are:
on the Wrangel island and the west of Alaska,
the north of Alaska,
the Canadian Arctic archipelago,
Svalbard - Ground of François-Joseph,
the northern center of Siberia.
The extent of its territory is limited by the availability of benches of drift ice on the sea, which they use as platform of hunting for the seal, its principal food. The destruction of its habitat on the Arctic ice-barrier threatens survival even of the species, the polar bear then which can die out at the end of the century. Harbingers were observed at the south-western ends of its territory.
The polar bears are solitary animals.
In the family of the bears, the polar bear is the member with the most carnivorous mode, since it nourishes mainly seals.
As a carnivorous predator, consuming fish, the polar bear introduces great quantities of vitamin has, which are stored in its liver: in the past of the explorers of the Arctic were often poisoned by eating the liver of an polar bear, because of a surdose of vitamin A.
The females are small (one or two in general) every three years old. They come in the world while the mother cut off herself in her den to winter: they do not awake it, being satisfied to nourish itself of the rich person mother's milk while tétant during several weeks. The mother takes along them out of the den only when they are old from three to four months: it is at this time only that they discover the world which surrounds them. The young people remain a long time near their mother. It is it which makes all their education: drive out, choice of a den, etc They separate definitively from the mother only at age the three years.
During this period, the small ones take much weight thanks to the milk produced by the female and which contains fat contents 50%.
The polar bear belongs to the red list of the species threatened of the UICN (International union for the Nature conservation). Previously classified in the category “risks weak, depend on the efforts of conservation” according to the red list drawn up in 1996, the polar bear from now on is classified in the “vulnerable” category. It is estimated that the species could disappear within one century because of a reduction of the surface and quality of its habitat [desired ref.].
In April/May 2008, of the discussions is in hand in the USA in connection with its possible classification on the national list of protected spaces. The federal government not having given an answer to the proposal for a classification of Fish and Wildlife Service (made in January 2007), a Federal judge ordered to the Minister of Interior Department (Interior Department) until May 15th to make its decision. The court rejected the argument of the government according to which the business was too complicated so that it can decide before June 30th, and it declared that once the decision taken, it would take effect immediately.
The habitat of the polar bears is naturally limited by the extent of the ice-barrier and the drifting ice floes of which they are useful as platform for hunting for the seal.
The survival of the polar bear is thus threatened by the climate warming which restricts their habitat while dissolving the ice-barrier. The first signs of a decline were already observed in the southernmost zones of their habitat, like Hudson Bay. No alternative solution such as the introduction of the polar bear in the Antarctic is currently seriously considered.
The discoveries of drowned polar bears, cannibalism, the number in increase of bear “with problems” - seeking bears of food close to the Arctic communities - are reported several areas to the range of the bears. These observations are coherent with the predicted changes caused by the warming of the climate.
Moreover, the widespread toxic matters in the sea are consumed by the phytoplankton then the zooplancton which in their turn are consumed by the fish, which themselves are eaten by the seals, the latter being the prey of the bears. Thus the bears store the poisons which accumulated in the organization of the animals which constitutes the food chain of the polar bears. One can also quote the exploitation of oil and gas like threats for the populations.
Drive out with the polar bear
Hunting for the polar bear is practiced by Inuits and the hunters of trophies.
The United States passed the Marine Mammal Protection Act in 1972 because the population of much of marine species had gone down drastiquement. The prohibited act to badger, wound or kill all the mammalian marine species, of which polar bears. It prohibits also the importation of “trophies” of polar bear in the United States.
The following year, 1973, the creation of International Agreement off one saw the Conservation Bears Whodunnit (also known under the name of the “Agreement of Oslo”), signed by the five nations whose Arctic territories are inhabited by this species: the United States, Canada, Norway and Denmark (via Greenland) and Russia (at the time still the USSR). He saw restrictions on hunting on the trophies and commercial and banishes hunting since the flying machines and the ice-breaker. For this year Norway has completely banished hunting for the polar bear and the United States, Greenland, Russia and Canada allows it within their people autochtones, leaving on the principle that it is part of their culture. Canada and Greenland allow hunting the trophies.
Canada, which shelters more polar bears that the other countries, allows a restricted hunting the trophies. The hunters pay a heavy tariff with the organizers of hunting to drive out polar bears. In 2005 the government of Nunavut increased the quota with 518 bears, in spite of protests of several scientific groups; approximately 50 were sold with hunters of trophies, the number remaining given to of Inuit. The government of the Territories of the North-West maintains its own quota from 72 to 103 polar bears within the Inuvialuit community; some are given to hunters of trophies.
Until 2005 Greenland did not impose limit on hunting on the polar bears by the indigenous population. This year it imposed a limit of 150 bears for 2006 and authorized hunting for the trophies for the first time.
In 1994 the United States modified the Marine Mammal Protection Act, allowing the importation of trophies of polar bears driven out by hunters of trophies and preparing the ground for a possible increase in hunting. For this year, more than 800 trophies of polar bears have been imported in the United States. In May 2007 a legislation was presented to the Congress to cancel the decision of 1994 and to prohibit the importation of the trophies.
Many associations of protection of the animals and environmental in general fear that climate warming does not have an enormous impact on the survival of the population of polar bears and that the continuation of hunting for the trophies does not have negative consequences yet.
State of protection
The five countries dividing the world population of polar bear, are Canada, the United States (via Alaska), Denmark (via Greenland), Norway and Russia signed in 1973 the International agreement on the conservation of the polar bears (polar) and their habitat. This agreement indicates that these countries must “act as it is advisable” to protect the polar bear and its habitat. The protection of the polar bear is the particular classification object on certain territories:
The United States: December 27th, 2006, in answer to an ultimatum coming in the term one year after order from the course following an legal action by Greenpeace and two other ecologists groups, the Department of the Interior of the US government proposed “to actively seek comments and scientific information” in order to determine if the polar bear were to be registered on the list of the threatened species. If such a decision were made, the US government would have obligation to protect the species and its habitat, the ice-barrier. According to the democratic member of Parliament ED Markey and the spokesperson of Greenpeace Kert Davies, that could result in a new American policy on the climate changes affecting the ice-barrier. For economic reasons related to the constraints that would involve on the oil exploitation in its state, the gouverneure of Alaska, Sarah Palin, wrote a letter of protest at the federal government to protest against the possible inscription of the polar bear among protected spaces.
Canada: In November 2002, the polar bear was classified in the category of the “alarming Species”, i.e. among the species sensitive to the effects of the degradation of their habitat by the natural man or phenomena, but without being threatened of disappearance, by the Committee on the situation of the species in danger in Canada. Inuits would be in discredit of a more important protection of the polar bear which would involve the prohibition of its hunting, traditional activity of their people and important economically for them.
Quebec: The species is classified “likely to be indicated threatened or vulnerable”