Freshwater Crocodile
Crocodylus johnstoni
Freshwater crocodiles are shy and secretive. They are much smaller in size and with a narrower snout than their cousin, the saltwater crocodile. ‘Freshies’ grow to between 1.5-2.5m long, and weigh between 30-60kg with females being much smaller than males. They are grey to olive-brown, with dark mottling along their backs and sides.
They inhabit inland rivers, swamps and billabongs in the north of the country, as well as some brackish areas, though they cannot live in seawater. Freshwater crocodile threats include other crocodiles and the ingestion of toxic cane toads.
WHAT THEY EAT
They will hunt for lizards, birds, or small mammals near the water’s edge, by ambushing them from the shallows. They will also actively hunt in the water for fish, frogs, turtles and insects, snapping them up in their jaws with a sideways motion. Their eyes and nostrils are on the top of their head so they can stay submerged whilst keeping an eye out for prey.
BREEDING
Females will lay up to 20 eggs in holes dug in the soft substrate near the water. They display temperature-dependent sex determination, with high or low nest temperatures resulting in female hatchlings, and mid-range temperatures resulting in males. Females don’t nest guard but will return upon hearing the nestlings call, to help excavate and carry them to the water.
It’s a fight for survival, with many eggs taken by predators like goannas, and most hatchlings not surviving the first year, often preyed upon by turtles, fish and other crocodiles. After one year, survival rates are much higher.