Amphibians have a three-chambered heart - two atria and one ventricle. The mixing of oxygenated and deoxygenated blood is kept to a minimum due to the timing of the contractions between the atria.

Amphibians like glass frogs become see-through whilst sleeping - and now scientists have discovered how. The creatures hide 90 per cent of their red blood cells in their liver, which is mirror-coated, ...

Glass frog photographed during sleep and while active, showing the differences in red blood cells within the circulatory system. Jesse Delia via AMNH When a tiny glass frog dozes off to sleep, its ...

Glassfrogs are able to pull off a “disappearing act” to hide from predators — turning much of their body see-through while they sleep — by hiding 90 percent of their red blood cells in a reflective, ...