They Might Be Giants

Part of the Lizards and Snakes: Alive! exhibition.

An artistic rendering of two Megalania, huge monitor lizards that lived in Australia during the Pleistocene Epoch. They are shown near low marshy water and feeding.
© Mark Hallett

Imagine rounding a bend and seeing this huge animal lying in wait! The earliest Australians probably had just that experience: Megalania (MEG-uh-LAIN-ee-uh) was still on the scene when humans first arrived in Australia some 40,000 or more years ago.

Megalania was huge, but estimating its exact size is tricky. Based on fossils, scientists think its length was at least three meters (10 feet) from the tip of its nose to the beginning of its tail-but how long was its tail? The tails of some large Australian monitors are about twice body length, and Megalania is a close relative of the living monitor lizards, so Megalania was probably at least six meters (20 feet) or even up to nine meters (30 feet) long. Either way, it is the largest squamate with legs ever to walk the Earth.