Here's why:
* Warm-blooded animals (also called endothermic) maintain a constant internal body temperature regardless of the external environment. They do this through internal mechanisms like shivering or sweating.
* Cold-blooded animals (also called ectothermic) rely on external sources like the sun to regulate their body temperature.
Yaks live in high-altitude, cold environments, and they need to keep their internal temperature stable to survive. They achieve this through their thick fur, layers of fat, and the ability to generate their own heat.