1. Temperature Regulation: Polar bears live in extremely cold environments. They have evolved several adaptations to maintain a stable internal body temperature:
* Thick Blubber Layer: A layer of thick blubber beneath their skin acts as insulation, trapping heat and preventing heat loss to the frigid air and water.
* Dense Fur Coat: Their fur is incredibly dense, with two layers: a thick undercoat for warmth and a long, oily outer layer for water resistance. This fur traps a layer of warm air close to their skin, further reducing heat loss.
2. Water Conservation: Polar bears spend a significant amount of time in the icy waters of the Arctic. They need to conserve water:
* Efficient Kidneys: Their kidneys are very efficient at conserving water, allowing them to produce concentrated urine and minimize water loss.
* Limited Sweating: Polar bears sweat very little, further reducing water loss. This is because they rely on their thick fur and blubber to regulate their body temperature, limiting the need for evaporative cooling.
These are just two examples of how polar bears maintain homeostasis in their harsh environment. They have numerous other adaptations that contribute to their survival.