The blue-belly crocodile is large, approximately 30 feet in length from snout to tail. Bony plates cover its back and tail forming a kind of armor on its thick skin. The crocodile has a long, triangular snout. Its teeth, 30 to 40 in each jaw, are set into sockets in the jawbones and interlock when the mouth is closed; the fourth tooth from the front on each side of the jaw can always be seen, even when its mouth is shut. It is amphibious, spending most of time in the water, where it swims with rhythmic strokes of its tail. The tail is also used to capture prey, sweeping it from shallow to deeper water, where it can be devoured more easily. As it floats almost completely submerged, the crocodile's protruding nostrils and eyes and a portion of its back are the only parts visible as it stalks its prey. It moves most quickly in a belly crawl, but can also walk on all four legs.