• 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 tissue earlier 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 most affected 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 always