Saltwater Crocodile
The saltwater crocodile, also known as the estuarine, marine or Indo Pacific crocodile and in Australia simply as the saltie, is the largest living reptile on the planet and one of the most powerful predators in the coastal ecosystems of Asia and Oceania. Adult males usually measure 4 to 5 meters and the largest pass 6 meters, while females remain considerably smaller. Its robust body, the strongest bite ever measured and salt glands that let it live in salt water allow it to move between rivers, mangroves, estuaries and open sea with an ease unmatched by other crocodiles. It is a patient ambush hunter, capable of remaining motionless for hours before striking with surprising speed. Although often associated with Australia, its range extends from India and Sri Lanka across Southeast Asia to the islands of the western Pacific, where it has coexisted with human communities for centuries.
Where do saltwater crocodiles live?
The saltwater crocodile has the widest range of any crocodile. It lives from the east coast of India and Sri Lanka through Bangladesh, Myanmar, Malaysia, Brunei, Indonesia, the Philippines and Timor Leste to Papua New Guinea, northern Australia and the islands of Palau, the Solomon Islands and Vanuatu. Its main habitats are estuaries, mangroves, tidal rivers, deltas and coastal swamps, but it also moves far up freshwater rivers and into floodplain lagoons, especially in the dry season. The best known locations to see one in the wild are the Adelaide River and Kakadu in Australia's Northern Territory, the Daintree River in Queensland, Bhitarkanika in India, the Sundarbans of Bangladesh and India, the Kinabatangan in Sabah and the Sepik in Papua New Guinea. The species has vanished from the Seychelles, and the IUCN considers it possibly extinct in Thailand, Cambodia and Vietnam, where hunting and the loss of mangroves wiped out the last wild groups.
How big is a saltwater crocodile? The largest ever measured
The saltwater crocodile is the largest living reptile. Adult males usually measure 4 to 5 meters and weigh 400 to 1,000 kilograms, and the biggest pass 6 meters and a tonne. Females are far smaller: they rarely exceed 3 or 3.5 meters and usually weigh 80 to 150 kilograms. The largest crocodile ever measured with certainty was Lolong, a male captured in Bunawan, in the Philippines, in 2011: he measured 6.17 meters and weighed 1,075 kilograms, and died in captivity in 2013. After him the record of the largest crocodile in captivity passed to Cassius, a 5.48 meter male kept on Green Island, in Queensland, who died in November 2024 at an estimated age of more than 110 years. Why are they so big? Crocodiles keep growing for much of their lives, although more slowly with age, and large males win territories and females, so size pays off. Older reports of crocodiles of 7 or 8 meters have never been confirmed.
Saltwater crocodiles in Australia
In Australia, where it is simply called the saltie, the saltwater crocodile lives across the tropical north: the Kimberley in Western Australia, the whole Top End of the Northern Territory, the Gulf of Carpentaria, Cape York and the east coast of Queensland south to around Rockhampton and Gladstone. It is not found in the south of the country. Commercial hunting for skins brought it close to collapse, and the Northern Territory had only about 5,000 left when hunting was banned there in 1971; Western Australia and Queensland protected it in 1970 and 1974. Today the Northern Territory alone has more than 100,000, one of the great wildlife recoveries of the twentieth century. Living with that many crocodiles takes work: rangers trap between 250 and 300 a year in and around Darwin Harbour, and warning signs line rivers, beaches and swimming holes. The jumping crocodile cruises on the Adelaide River, the Yellow Water billabong in Kakadu and Cahills Crossing on the East Alligator River are the classic places to see them.
What do saltwater crocodiles eat?
The saltwater crocodile is an opportunistic carnivore that feeds on almost any animal it can overpower. Hatchlings and juveniles eat insects, crabs, shrimp, small fish and frogs. As they grow they switch to bigger prey: fish such as barramundi and mullet, turtles, snakes, waterbirds, monkeys, wallabies, wild pigs and deer. The largest males can take water buffalo, cattle and horses that come down to drink, and sharks have been found among their prey in Australia. Its technique is the ambush: it waits almost completely submerged, with only its eyes and nostrils above the surface, and then lunges with an explosive burst. Once it has a grip, it drags the prey underwater to drown it and uses the death roll, spinning its whole body to tear off pieces, because it cannot chew and swallows meat in large chunks. A large crocodile can go months between big meals, since its slow metabolism uses very little energy.
Are saltwater crocodiles dangerous? Why they are so aggressive
Yes. Together with the Nile crocodile, the saltwater crocodile is the crocodile that kills the most people. Its reputation for aggression has simple reasons: large males defend stretches of river or coast against anything that enters, females guard their nests fiercely, and a big crocodile sees any animal at the water's edge, including a person, as possible prey. Most attacks happen to people who fish, bathe, wash clothes or collect water in rivers and estuaries. Indonesia records more attacks than any other country, many of them around the flooded tin mines of Bangka Belitung, and Timor Leste has one of the highest attack rates in the world relative to its population. In Australia attacks are rarer thanks to warnings, education and the removal of problem crocodiles, but they still happen most years in the north. The basic rules in crocodile country are to obey warning signs, never swim in rivers or estuaries, keep several meters back from the water's edge and never clean fish or camp right next to it.
Behavior: territories and journeys out to sea
Outside the breeding season the saltwater crocodile lives a mostly solitary and territorial life. Adult males hold stretches of river or coast and drive out rival males, while young males are pushed away and often have to travel far to find a place of their own. It is active by day and by night, and spends many hours basking on banks to warm up or lying with its mouth open to cool down. Its tolerance for salt water comes from salt glands on the tongue that get rid of excess salt. That lets it travel by sea, and it does so cleverly: a study in Queensland's Kennedy River, led by Hamish Campbell with the late Steve Irwin, showed that crocodiles ride surface currents and tides instead of swimming against them. One 3.84 meter male covered 590 kilometers in 25 days along the coast of Cape York. These journeys explain how the species reached remote islands such as Palau, the Solomon Islands and Vanuatu.
Nests and baby crocodiles
Saltwater crocodiles nest in the wet season, which in northern Australia runs from about November to March. The female builds a mound of mud and plant matter near the water, often on a floating mat of vegetation or a riverbank, and lays about 40 to 60 eggs. The heat of the rotting plants and the sun incubates them for around 80 to 90 days. The temperature inside the nest decides the sex of the babies: nests at around 32 degrees produce mostly males, while cooler or hotter nests produce females. The female stays close and defends the nest, but floods drown many clutches and monitor lizards and pigs dig up others. When the hatchlings are ready they call from inside the eggs; the mother opens the nest and carries the babies to the water in her mouth, and guards them for a few weeks. Even so, only about one egg in a hundred produces a crocodile that reaches adulthood. Females mature at around 10 to 12 years and males at about 16.
Is the saltwater crocodile endangered?
No. The IUCN lists the saltwater crocodile as Least Concern, and the Crocodile Specialist Group estimates more than 400,000 wild crocodiles, not counting hatchlings. That global number hides very different situations. Australia, Papua New Guinea and Indonesian Papua hold large, secure populations, and in Sarawak numbers have grown enough to cause conflict. Elsewhere the species is scarce: small groups survive in Bhitarkanika and the Sundarbans, in the Ayeyarwady Delta in Myanmar and in parts of the Philippines, and it has disappeared from the Seychelles and possibly from Thailand, Cambodia and Vietnam. Skin hunting caused the great collapse of the twentieth century; today the main threats are the clearing of mangroves for shrimp farms and settlements, drowning in fishing nets and the killing of crocodiles after attacks. International trade is controlled by CITES: the species is in Appendix I in most countries, while the healthy populations of Australia, Papua New Guinea, Indonesia and Sarawak are in Appendix II, where trade in farmed and ranched skins is allowed under strict rules.
Where it is found
The Saltwater Crocodile can be found in places such as:
