Polar bears are the world's largest land predators. They are large and stout, with a shoulder height of 1.6 meters. The adult male polar bear weighs 300-800 kg and has a head and body length of 2.5 meters. Female polar bears are smaller, weighing 150-300 kg and 1.8-2 meters long.

Polar bears live in ice covered waters of the Arctic circle. In winter, the depth of the cave can reach permafrost. The preferred habitat is ice floes in the Arctic Ocean. The broken and frozen periglacial and pressure ridges provide the best hunting ground for polar bears. They generally act alone, except during mating and lactation.

Polar bears are so excellent swimmers that they were once considered marine animals. Polar bears spend most of their lives (about 66.6%) in a "static" state, such as sleeping, lying down, or waiting for their prey. The rest of their time walking, swimming, tracking prey or eating.

Sometimes the hard-earned prey of polar bears will attract the prying eyes of the same kind. Generally speaking, if they are unlucky to face those big guys, the smaller polar bears will be more inclined to run away. However, a mother who is feeding her baby will sometimes compete with the big male bears who come to offend in order to protect her baby or defend the hard-earned rations of the family.

There are more than 20000 wild polar bears living in the world, and the number is relatively stable. To protect their survival, as early as 1972, the United States enacted a law prohibiting the hunting of polar bears in addition to survival needs. In 1973, the countries in the Arctic Circle, including the United States, Canada, Norway, Denmark, and the former Soviet Union, further signed the International Convention for the protection of polar bears. In addition to restricting hunting and trade, the Convention also further proposed provisions for the protection of their habitats and cooperative research.