Hummingbirds can enter a hibernation-like state at night, dropping their body temperature to under 4°C in an effort to preserve energy for use during the day.

The birds are one of a few species, including night hawks and some small rodents , that are capable of torpor, in which body function reduces to a bare minimum for a few hours, says Blair Wolf at the University of New Mexico.

Previous studies have found that hummingbirds can drop their body …