What characteristics would you expect tundra animals to have?

i'd expect tundra animals to have the proper adaptations for their environment. So maybe some sort of insulation to keep warm, like fur or a thicker layer of fat. Hibernation is also another characteristic certain animals may have.

Also, another characteristic could be the instincts of how to hunt the appropriate prey.

Explanation:

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.

the electromagnetic energy from the sun arrives in the form of visible and invisible light.