Tuesday, September 22, 2020

"This hummingbird survives cold nights by nearly freezing itself solid"

The black metaltail of the Andes:

During the day, these hummingbirds’ tiny-yet-mighty hearts can beat 1,200 times a minute to power their frenetic lifestyle. But during torpor, their heart rates plummet to as low as 40 beats a minute. “It’s an astounding drop,”

...

Around sunrise, the hummingbirds start revving up, warming about a degree a minute by vibrating their muscles. “You see the bird quivering there, then all the sudden its eyes pop open and it’s ready to go,”