Experts at Washington University in St. Louis are describing how hummingbirds use torpor, a hibernation-like state of inactivity, to survive harsh environments. According to the study, hummingbirds use torpor in different ways depending on their physical state and the environmental conditions they are facing.  In collaboration with biologists in Colombia, the researchers caught 249 hummingbirds (29 different species) living in the middle to high altitudes of the Andes Mountains. The experts wanted to measure torpor under various semi-natural conditions.  “Torpor is somewhere between a power nap and...