Habitat: Brackish and freshwater areas such as mangrove forests, rivers, estuaries, creeks, swamps, lagoons and billabongs
Distribution: Southwestern India and Sri Lanka, south-eastern Asia, and Northern Australia
Lifespan: Unknown in the wild, but are expected to live for 70 years or more
Conservation status: Least Concern
Main threats: Fishing nets, habitat destruction, illegal hunting, habitat loss, and antipathy toward the species
About
Earth’s largest living crocodilian, and the largest living reptile in the world, is the saltwater or estuarine crocodile (Crocodylus porosus).
The estuarine crocodile has a broad snout, with extremely powerful jaws responsible for creating the strongest bite in the animal world. Their colouring ranges from almost black to grey and olive-brown, with ragged, dark mottling.
This species is sexually dimorphic. Adult males are, on average, 5m long and weigh more than 450kg, while females are much smaller, generally around 3m long and up to 150kg.
Saltwater crocodile leather is in high demand, and farms are established to raise crocodiles solely for their hides which are used most often in shoes and handbags. Like other animal skin trades, this practice is highly controversial.
Did you know: The species is no longer found in much of its original range due to the destruction of habitat and over-hunting.
Behaviours
Saltwater crocodiles are cold-blooded and rely on external sources of heat to warm up.
They are ambush predators that lie in wait for fish or animals to come close, before rushing forward to attack. They will eat just about any animal they can get their jaws on, including water buffalo, monkeys, wild boar, and even sharks. They can also attack and kill domestic livestock and even humans.
Saltwater crocodiles breed in freshwater during the wet season. Courtship begins in October to November, with nesting spread over several months from December to April.
During the breeding season, male crocodiles become very mobile as they look for a mate and drive off rival males. Females also become intolerant of other females and will jostle for dominance.
After mating, the female deposits between 40-60 eggs on average, but can lay as many as 90 at a time. She buries her eggs in nests of vegetation and mud which are elevated to avoid loss from flooding during the rainy season. Females protect their nests until the eggs are hatched between 65 and 114 days depending on nest temperature.
Sex is also determined by nest temperature. Males are produced at around 31.6° C. Any deviation from that temperature will result in a female hatchling.
As they hatch, the young will begin to ‘chirp’ to attract the attending female. After helping dig out the hatchlings, the female carries them in her mouth down to the water where she will continuesto protect them until they learn to swim.
What should you do if you encounter a crocodile?
- Stay calm and back away.
- Do not approach, provoke or feed the animal.
Having a connected rainforest is crucial to the long-term survival of this species. You can help protect saltwater crocodile habitat in the Daintree. Find out how.