This photo provided by researchers in December 2022 shows a glass frog, strict leaf dwelling frogs, that sleep, forage, fight, mate, and provide (male) parental care on leaves over tropical streams. Some frogs found in South and Central America have the rare ability to turn on and off their nearly transparent appearance, researchers report Thursday, Dec. 22, 2022, in the journal Science. Credit: Jesse Delia/AMNH via AP Now you see them, now you don't. Some frogs found in So...