A number of physical and behavioral adaptations allow polar bears to survive in their environment (harsh tundra regions). Behaviorally polar bears are very solitary animals and spend most of their lives alone, since there is very little life in Tundra and competition for food is great. Polar bears exhibit some aggression to protect their cubs or food and to compete for females. The mode of communication is typically vocalization and sign language. Pregnant polar bears hibernate through the winter in their dens and their cubs are born in den, protected from harsh weather outside, and hence are healthier and have better survival chances. They use the body fat during hibernation (since they are fasting) and can also use it during conditions of food scarcity (and not just during hibernation).
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