During the day, hummingbirds maintain a high, constant body temperature, but at night they can lower their metabolism to save energy and allow their body temperatures to fall by as much as 20°C.Hummingbirds are therefore
A) endotherms.
B) ectotherms.
C) heterotherms.
D) pyrotherms.
E) varitherms.

Question

Quizplus · Accepted Answer

Hummingbirds are able to lower their metabolism and allow their body temperatures to fall significantly at night, which is a characteristic of heterothermic animals. They are not ectothermic (reliant on external sources to regulate body temperature) or pyrothermic (reliant on heat production from metabolism) as they can maintain a high body temperature during the day. Varitherms is not a term used to describe animal thermoregulation.

During the Day, Hummingbirds Maintain a High, Constant Body Temperature