11. We do know this: About 52.5 million years ago in what’s now Wyoming, early bat Onchonycteris finneyi was already capable of powered flight.
12. Bats are the only mammals with this trait; they also take to the skies differently than other flying animals. Unlike the more rigid wings of birds and insects, bat wings have multiple joints and move in and out as well as up, down, back and forth with every stroke.
13. One thing bats do have in common with birds: According to research released in June, the outer layer of their skin contains a compound that enhances pliability — handy when flight depends on your flexible wings. No other mammal has this adaptation.
14. You might think echolocation is another defining Chiroptera trait, but not all bats send out sound waves that bounce off prey and potential obstacles to create a picture of their environment.
15. Fruit bats, for example, generally rely on their eyesight to find food. For decades, it was assumed they didn’t echolocate, and most don’t. But a 2014 study found three fruit bat species sometimes use a rudimentary method of echolocation: They make a clicking noise with their wings to navigate in darkness.
16. If not for the Vikings, we might call a bat a “rearmouse.” It derives from the Anglo-Saxon term for the animal, hreáðe-mús. As Norsemen moved into what’s now the United Kingdom, beginning in the ninth century, bakke, of Scandinavian origin, gradually replaced the word and evolved into bat.
17. “Rearmouse” persists colloquially today in areas of Great Britain that never fell under Scandinavian influence, including pockets of Wales and England’s southwest.
18. Bats jam. Seriously. A 2014 Science study found that when competing for food, Mexican free-tailed bats emit an ultrasonic signal that effectively blocks the sound waves another bat sends out to home in on an insect. The interference causes the rival to miss its target.
19. Something else that’s off-target: the myth that bats get tangled in long hair. Some scholars trace the notion to an early Christian edict that women must cover their heads because their hair attracted demons. Already associated with devilish things, bats were assumed also to have a thing for hair.
One more fiction that makes us batty is the whole vampire thing. Only three of the more than 1,200 bat species are sanguivorous. Any bat you meet is far more likely to eat a mosquito or pollinate fruit than go for your jugular.