Which is the largest living reptile?

The saltwater crocodile is the largest living reptile, with big males passing six metres and weighing over a tonne. Despite the name, it is not confined to the sea. It lives in estuaries, rivers and coastal swamps across northern Australia and southern Asia, and it tolerates salt water well enough to travel long distances between river systems, riding ocean currents rather than swimming the whole way, which is how the species spread so widely. It is an ambush predator, holding still at the surface with almost nothing showing, then launching with a burst of power and dragging prey under. Its bite force is among the strongest measured in any animal, though the muscles that open the jaw are weak by comparison. Crocodiles keep growing slowly throughout life and are long-lived, so the largest individuals are old ones, and males grow considerably bigger than females.

In many crocodiles and turtles the temperature of the nest determines whether the eggs produce males or females.