As tiny glass frogs fall asleep for the day, they take almost 90 percent of their red blood cells out of circulation. The colorful cells cram into hideaway pockets inside the frog liver, which ...

Glass frogs have the rare ability to turn on and off their nearly transparent appearance, researchers report Thursday in the journal Science. Ernesto Benavides/Getty Images Now you see them, now you ...

Glass frogs can boost their transparency by up to 61 per cent by storing most of their blood in their liver while they sleep. Researchers hope that understanding how the frogs manage to pool their ...