Polar Bear

The Polar Bear is found in the circumpolar Arctic region. Due to rapid human development and activities like poaching, the number of polar bear has declined to less than 25000. Furthermore, the loss of sea ice and climate change due to various factors are pushing the number of polar bears lower.Polar bears are considered to be mainly marine animals and spend much more time on the sea ice than they do on land. They can swim several hundred kilometres without resting and can dive under water for up to one minute.Polar bears are at the top of the Arctic food chain. They prefer to remain on the sea ice, where they hunt their main prey, ringed seals.In many areas of the Arctic, polar bears remain on the ice year-round. It is only in areas where the ice melts in the summer, such as Hudson Bay, that the bears are forced ashore until the ice refreezes in autumn.Polar bears are the largest land carnivores in the world! An average adult male weighs 500 kg to 600 kg and reaches maximum size by eight to 10 years of age. Male bears reach their maximum weight in their early teens.

An average adult female is about half the size of a male, weighing 200 kg to 300 kg and reaching maximum size by age four or five. Cubs weigh only 0.6 kg (about 1 lb.) at birth. The lifespan for males is more than 20 years and for females, more than 25 years.Polar bears are well adapted to live in the Arctic. Parts of their bodies are covered with a thick layer of fat called adipose tissue that protects them from the cold and adds buoyancy in the water. During the long months of fasting, bears depend on these fat reserves for survival. They also play an important role in reproductive success.

If a pregnant female has an insufficient store of adipose tissue, she will have insufficient energy to feed her cubs, to fast, and to return to her preferred hunting grounds at ice freeze-up.Both males and females become mature at four to five years, although most males probably do not breed until eight to ten years.

Polar bears mate out on the sea ice in spring. The female has delayed implantation. That means that the fertilized egg develops to a multicellular state and then stops developing until it is implanted in the uterus in September or October.Females usually give birth to twins, although a litter can range from one to three cubs.