Adaptations of polar bear
Answers
Low surface area to volume ratio (anatomical) - Compared to other species of bears, polar bears have small extremities, proportionally shorter legs and a stockier build. This reduces the surface area to lose heat from. This is a common characteristic amongst animals that live in cold environments that enables them to retain their heat and conversely means they often can't cope with warm temperatures as they easily overheat in warmer temperatures.
Small extremities to reduce heat loss (anatomical) - Polar bears have small ears covered in thick fur, a very short tail and a relatively short and squat muzzle, all of which help to retain heat.
Polar bears eat a very high fat diet and have adaptations to allow them to process this food (physiological) - *This is possibly the key adaptation that polar bears have*. It enables them to eat the blubber of the seals that they catch which is the most energy rich and abundant part of the seal. Other animals could simply not survive if they ate so much fat in their diet. Adult bears often only eat the blubber while younger still growing bears will also eat the meat for protein.
Strong legs for swimming and running