• by pollution
The polar bear is a super predator that is has no direct enemy in Antarctica, also hunting is regulated. However, it was added to the red list of endangered in 2006.
This may seem hard to believe, but the polar bear is threatened by our daily actions. Thousands of kilometers separating us insufficient to protect it.
For several years,Canadian and Norwegian scientists themselves are previews that our industrial pollutants have previously moved past to the Arctic by air and sea currents. This pollution is plant plankton to krill (plankton from the cold seas formed small transparent crustaceans) and then to Arctic Cod. Toxic substances such as PCBs (persistent organic pollutants) eventually focus the greasy animals, more tissueearlier in the food chain. The seal, primary source of polar bears, food is contaminated. PCBs are concentrated in the bear grease and will be spilled blood animal when it will undergo a prolonged fasting the oblige to use its reserves of grease. It should be noted that there is a higher concentration of PCB in Arctic countries that produce.This abnormal rate of pollutant causes significant problems in bears:
-Disruption of the endocrine system, therefore reproduction and growth.
-Birth defects at the teddy bears.
-Weakening of the immune system.
We may report such instances of hermaphrodite observed on polar bears. The teddy bears are contaminated by the placenta and breast milk. Bear populations mostaffected are located on the islands of Svalbard (Spitsbergen), Norway. For its part, Hudson Bay bear population is threatened by hybridization, now documented between Alaskan Grizzly and polar bears. More clement temperature allows grizzly bears migrate more north polar bears are increasingly reduced to hunt on the coasts, which allows two species are confronting, not alwaysharmoniously elsewhere.
• by warming
The reproduction is not only affected by the disruption of the endocrine system of polar bears. As in other species of bear, poor physical conditions may interrupt the implantation of the fertilized ovum in the uterus. The scopes that were usually composed of 2 to 3 small byte more than one and the mothers are sometimes too weak to feed the teddy bears.Furthermore, the onset of rain in the winter is sometimes melt repairs in which the bear’s female put down, exposing small cold and predators. The teddy bears mortality rate is very important. The White bear finds much of its power between April and July. Sea ice is the polar bear hunting territory and its reduction causes undernourished and fasting periods moreloins. Cases of cannibalism were reported by observers. These behaviors were considered "normal" when males attacked the teddy bears to reproduce with females, Alaska Labs scientists reported in 2004 three disturbing dead on a young male and two females.
by the pressure of human activities
Until now, polar bear territory was preserved and the pressure of the man in these lands was anecdotal. But theconstant search for new oil deposits begin to gangrened the North Pole. According to some estimates, the arbitrate one quarter of the world's reserves of oil! Despite the risks of pollution very important oil tankers will show very interested by these untapped stocks. Certainly, that is why we intend to recently some scientists take a completely opposite to that of all specialists who derive thealarm bell speech and who have requested protection of polar bears and their habitat. Increase protection, is to limit human activities compete with this species, so extremely lucrative oil activities. Since the opening of new sea routes for the transport of oil could disrupt further polar bears by reducing its habitat. AT present, the Panama canal serves as a link between the Atlantic Ocean and...