Hummingbirds use torpor in varying ways to survive cold temps

Hummingbirds have the fastest metabolism of any animal. The tropical hummingbirds that live in the Andes Mountains in South America must expend considerable energy to maintain their high body temperatures in cold environments. One tool that they use to survive cold nights is called torpor, a hibernation-like state that allows them to ramp down energy consumption to well below what they normally use during the day.