Here's why:
* Endotherms are animals that regulate their own body temperature internally. They generate heat through metabolic processes and can maintain a relatively stable body temperature regardless of the external environment.
* Ectotherms rely on external sources of heat, like the sun, to regulate their body temperature. Their body temperature fluctuates with the temperature of their surroundings.
Grizzly bears are warm-blooded mammals, meaning they are capable of maintaining a consistent internal body temperature, even in cold environments. This is a key characteristic of endotherms.