Animal
Saltwater crocodile
The saltwater crocodile is the biggest reptile in the world. It lives in rivers, swamps and along the coast, and it can even swim in the sea.
The saltwater crocodile is the largest reptile alive today. It lives in rivers, swamps and estuaries from India to northern Australia, can cope with fresh water and seawater, and sometimes swims far out across the open ocean to reach distant islands.
Crocodylus porosus, the estuarine or saltwater crocodile, is the largest living reptile. It tolerates salinities from fresh water to full seawater, ranges from India and Sri Lanka to northern Australia and the Solomon Islands, and has recovered strongly in Australia since protection in the 1970s; the IUCN lists it as Least Concern.
Photo: Obtained from Molly Ebersold of the St. Augustine Alligator Farm, public domain, via Wikimedia Commons
Meet the saltwater crocodile
The saltwater crocodile is the biggest reptile on Earth.
It has a long tail, bumpy skin and a big, wide snout. Its eyes and nose are on top of its head. It can live in rivers and in the salty sea.
The saltwater crocodile is the largest reptile alive today. It is often called a 'saltie', and also the estuarine crocodile, after the estuaries where rivers meet the sea.
An average adult is 3 to 5 meters long, and males grow much bigger than females. Its broad snout is lined with teeth, its back is covered with bony plates, and its eyes and nostrils sit on top of its head, so it can watch and breathe while almost hidden underwater.
Crocodylus porosus is the largest living reptile by mass and the largest crocodilian by confirmed measurements (crocodilian.com). The Australian Museum gives an average adult total length of 3 to 5 meters; the largest reliably measured animal, caught on the Mary River in the Northern Territory in 1974, was at least 6.15 meters, and the largest reliably measured female was 4 meters. A 5-meter adult weighs roughly 400 to 500 kilograms, and very large males have exceeded 1,000 kilograms.
The snout is broad, less than twice as long as the head is wide, which helps tell it apart from Australia's slender-snouted freshwater crocodile. In large adults a pair of ridges runs from the eyes along the snout.
Quick facts
- Group
- Reptile
- Length
- 3 to 5 m
- Weight
- 400 to 500 kg
Where it lives
Saltwater crocodiles live in warm places.
They live in Asia and in the north of Australia. They swim in rivers, swamps and along the coast. Some even swim across the sea to faraway islands.
Saltwater crocodiles live from India and Sri Lanka across Southeast Asia, the Philippines and Indonesia to northern Australia and the Solomon Islands. In Australia they live along the northern coast, from Broome to near Gladstone.
They use many watery homes: rivers, estuaries, creeks, swamps, lagoons and billabongs. They can live in fresh water or seawater, and some travel across stretches of open ocean. Crocodiles have turned up on remote islands, and a few travelers have even been found with barnacles growing on their scales.
The species ranges from southwestern India and Sri Lanka through Southeast Asia, the Philippines and the Indonesian archipelago to northern Australia, New Guinea and the Solomon Islands. The IUCN lists it as possibly extinct in Cambodia, Thailand and Vietnam and extinct in the Seychelles.
It tolerates salinities from 0 (fresh water) to 35 parts per thousand (seawater), and has been recorded in water about twice as saline. Individuals cross large stretches of open sea; strays have reached remote islands such as Fiji, and a few strays far from the usual range have been found with barnacles on their scales. Social pressure also moves animals: young adults unable to win a territory in a tidal river are pushed into marginal or saline areas or out to sea.
Continents
Where can you find this animal?
- Used to live here · Countries and seas named by a scientific source
- Lives here naturally · Countries and seas named by a scientific source
- Sightings recorded · Records of wild sightings (GBIF)
Used to live here · Countries and seas named by a scientific source
Countries where the IUCN lists the saltwater crocodile as possibly extinct.
Places: Cambodia, Thailand and Vietnam.
Source: iucn-red-list · checked October 2026
Lives here naturally · Countries and seas named by a scientific source
Coastal rivers, estuaries, swamps and lagoons from India and Sri Lanka through Southeast Asia and Indonesia to northern Australia, New Guinea, the Solomon Islands and Vanuatu. Crocodiles live only near the coasts and rivers of the countries shown.
Places: Australia, Bangladesh, Brunei, India, Indonesia, Malaysia, Myanmar, Papua New Guinea and 5 more places.
Source: iucn-red-list · checked October 2026
Sightings recorded · Records of wild sightings (GBIF)
Counts of GBIF records of wild observations (human and machine) and preserved specimens. Records include introduced populations, vagrants, escaped or released animals and misidentifications, so a country with records is not necessarily part of the native range.
Wild sightings have been recorded in Australia, Malaysia, Indonesia, India, Sri Lanka, Papua New Guinea, Timor-Leste, Brunei and 23 more places.
Source: gbif · checked October 2026
Range maps show where scientists say an animal lives, often country by country. An animal may live in only part of a country shown, and sightings records can include animals that wandered far from home.
What it eats
Saltwater crocodiles eat other animals.
Babies eat bugs, crabs and small fish. Big crocodiles eat fish, birds and bigger animals. They often hunt at night.
Saltwater crocodiles are carnivores. Young crocodiles catch insects, crabs, frogs and small fish, often by waiting quietly in shallow water. As they grow, they add turtles, lizards, snakes and water birds, and the biggest adults can catch large mammals.
Even so, small animals make up most of what adults eat. Crocodiles mostly hunt at night, and they also eat dead animals they find. Because a crocodile's stomach is small, it may save part of a big meal to eat later.
The diet broadens with size. Juveniles take insects, amphibians, crustaceans, small reptiles and fish, often by sitting and waiting in shallow water; adults add mud crabs, turtles, goannas, snakes and shore and wading birds, and large adults occasionally take mammals up to the size of buffalo. Small prey still makes up most of the diet even in large adults.
Hunting is mostly nocturnal, with a stealthy approach underwater and a fast lunge. Small prey is crushed and swallowed whole. Saltwater crocodiles also scavenge carrion, and because the stomach is relatively small they may cache leftovers in mangroves or underwater.
Did you know?
A crocodile tosses its food in its mouth before it swallows.
A crocodile's tongue cannot move much, so it tosses its food around in its mouth to get it into position to swallow.
With a relatively immobile tongue and skull bones, crocodiles reposition food by tossing it in the mouth before swallowing.
Built for water
A crocodile's eyes and nose are on top of its head.
It can float and still see and breathe. Its strong tail pushes it through the water. Its feet have claws and a little webbing.
A saltwater crocodile has the classic crocodile shape: a long snout full of teeth, eyes and nostrils on top of the head, a streamlined body, short legs with clawed, webbed feet and a long, muscular tail for swimming.
Its skin has bony plates called osteoderms set into it, but only on its back and neck. Its belly has smooth, even scales. Adults are tan, gray or nearly black with darker blotches, while babies are pale tan with bold black stripes and spots.
The body follows the typical crocodilian plan: a long, well-toothed snout, dorsal eyes and nostrils, a streamlined trunk, short limbs with clawed, webbed feet and a long, muscular tail. Osteoderms are restricted to the back and a small cluster on the neck; the belly scales are small, rectangular and even, without osteoderms.
Adults range from golden tan to gray or black with darker mottling and a creamy belly; juveniles are pale tan with black stripes and spots, a pattern that fades but never fully disappears. The tongue and skull bones are not very movable, so crocodiles toss food in the mouth to position it for swallowing.
Nest, eggs and hatchlings
A mother crocodile builds a big nest of plants and mud.
She lays about 50 eggs and guards them. When the babies chirp, she digs them out. She carries them to the water in her mouth.
Saltwater crocodiles nest in the wet season. The female scrapes plants and earth into a mound up to 2.5 meters long and lays around 50 eggs inside. She often stays in a muddy pool beside the nest to guard it.
The temperature of the nest decides whether each baby will be male or female. After two to three months, the hatchlings start to chirp. Their mother digs them out and carries them gently to the water in her mouth. Very few babies grow up: floods drown many nests.
Nesting runs through the wet season, from late October to about May or June in the Northern Territory. The female builds a mound of vegetation and earth up to 2.5 meters long and 80 centimeters high, usually within 20 meters of permanent water, and lays up to 71 eggs, about 50 on average. Heat from decomposing vegetation and the sun incubates them.
Sex is set by incubation temperature. The Australian Museum summarizes it as cooler nests tending to produce females and warmer nests males; the crocodilian.com species account adds detail, reporting the most males at about 31.6 °C, with more females a few degrees above and below. Hatching follows after two to three months. Up to 75 percent of eggs may fail, mostly from flooding, overheating or infertility. Females mature at about 2.2 to 2.5 meters (10 to 12 years), males at about 3.2 meters (around 16 years).
Keeping warm and finding home
Crocodiles lie on muddy banks to warm up in the sun.
When it is too hot, they rest in the shade or in the water. Crocodiles can find their way home from far away.
Saltwater crocodiles control their body temperature by moving between sun, shade and water. In cooler months they bask on mud banks, and in the hottest months they keep to the shade of mangroves or the water.
They are also very good at finding their way home. In one Australian study, crocodiles moved to a different river found their way back to where they had been caught, some in as little as 10 days. Crocodiles talk with sounds too: babies chirp to their mother, and adults growl.
Studies suggest saltwater crocodiles rarely let their body temperature rise much above 35 °C before moving into water or shade; in the Northern Territory large animals bask on open mud banks in June and July but avoid the sun from October to December.
They show strong homing. In a Northern Territory study of 'problem' crocodiles moved to other river systems, recaptured animals returned a mean straight-line distance of 25.6 kilometers, taking from 10 days to 3.7 years, so relocation is not an effective way to manage them. Communication uses sounds (hatchling chirps, growls), postures such as raising the snout in submission, and possibly musk from glands under the chin.
Did you know?
Baby crocodiles chirp to call their mother.
Hatchlings chirp to get their mother's attention and to keep their group together.
Hatchling chirps both summon the attending female and keep the creche together; adults growl, and males growl to advertise themselves in the breeding season.
Crocodiles and people
Long ago, people hunted many crocodiles for their skins.
Now they are protected, and there are many more in Australia. Near crocodile rivers, people stay well back from the water and read the warning signs.
Before the 1970s, saltwater crocodiles were hunted heavily for their valuable skins, and their numbers fell. Since they were protected, they have made a big comeback in Australia, and the species is now listed as Least Concern.
In some other countries they are still rare, and they face habitat loss and being killed out of fear. In places where crocodiles live, people stay safe by obeying warning signs, keeping well back from the water's edge and making sure children stay with a grown-up.
The IUCN assessed C. porosus globally as Least Concern in 2019, estimating about 500,000 mature individuals with a stable trend. Unregulated hide hunting, mainly between 1945 and 1970, caused steep declines; since protection in the 1970s, Australian populations have recovered and reclaimed much of their former range. Elsewhere the picture is weaker: the IUCN lists the species as possibly extinct in Cambodia, Thailand and Vietnam, and habitat loss, drowning in fishing nets and killing out of fear remain threats.
In the Northern Territory, sustainable-use programs pay landowners for wild eggs collected for farms, giving people a reason to keep wetland habitat. Public education and warning signs aim to protect both people and crocodiles.
IUCN Red List
How is the saltwater crocodile doing in the wild?
- Least Concern (this animal)
- Near Threatened
- Vulnerable
- Endangered
- Critically Endangered
- Extinct in the Wild
- Extinct
Least Concern
Not at risk of disappearing from the wild right now.
See the IUCN Red List assessment · The IUCN Red List of Threatened Species 2022.2
Amazing facts
-
Some saltwater crocodiles have barnacles growing on them, like a ship!
Saltwater crocodiles can travel more than a thousand kilometers by sea, and barnacles have been found growing on the scales of a few strays.
Long-distance sea travel, of over a thousand kilometers, is shown by strays far outside the range, a few carrying barnacles on their scales.
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Baby crocodiles chirp to call their mother.
Hatchlings chirp to get their mother's attention and to keep their group together.
Hatchling chirps both summon the attending female and keep the creche together; adults growl, and males growl to advertise themselves in the breeding season.
-
Crocodiles can find their way home from far away.
Crocodiles moved to other rivers in an Australian study found their way back home, some in only 10 days.
Relocated Northern Territory crocodiles homed over a mean straight-line distance of 25.6 kilometers, in 10 days to 3.7 years.
-
A crocodile tosses its food in its mouth before it swallows.
A crocodile's tongue cannot move much, so it tosses its food around in its mouth to get it into position to swallow.
With a relatively immobile tongue and skull bones, crocodiles reposition food by tossing it in the mouth before swallowing.
Words to know
- estuary
- the place where a river flows into the sea and fresh water mixes with salt water
- osteoderms
- bony plates in the skin that work like armor
- reptile
- a cold-blooded animal with scales that usually lays eggs, such as a crocodile, lizard or snake
- hatchling
- a baby animal that has just come out of its egg
- billabong
- an Australian word for a pool or pond left behind when a river changes course or dries back
- homing
- being able to find the way back to a home place
Discovery challenge
-
What is special about the saltwater crocodile?
What record does the saltwater crocodile hold?
Which superlative applies to Crocodylus porosus?
- It is the biggest reptile alive
- It is the fastest animal on land
- It is the smallest crocodile
Show the answer
It is the biggest reptile alive
It is the biggest reptile in the world!
It is the largest reptile alive today; average adults are 3 to 5 meters long.
It is the largest living reptile; the largest reliably measured individual was at least 6.15 meters.
-
Where can saltwater crocodiles live?
Which kinds of water can saltwater crocodiles live in?
What range of salinity does C. porosus tolerate?
- Only in ice-cold lakes
- In fresh water and in salty seawater
- Only in fresh water
Show the answer
In fresh water and in salty seawater
They live in rivers and in the salty sea.
They live in rivers, swamps and estuaries and can swim in the sea.
From 0 to 35 parts per thousand (seawater), and they have been recorded at about 70.
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How does a mother crocodile take her babies to the water?
How does a female saltwater crocodile move her hatchlings to the water?
What does the female do when hatchlings start chirping?
- She leaves them alone
- She rolls them like balls
- She digs them out and carries them in her mouth
Show the answer
She digs them out and carries them in her mouth
She carries them gently in her mouth.
When the babies chirp, she digs them out of the nest and carries them to the water in her mouth.
She excavates the nest and carries hatchlings to the water in her mouth, then guards them for some time.
-
Near a crocodile river, what should you do?
What is the safe thing to do in crocodile country?
Which precaution does the Australian Museum recommend near crocodile habitat?
- Stay well back from the water and obey warning signs
- Go paddling in muddy water
- Leave fish scraps by the water
Show the answer
Stay well back from the water and obey warning signs
Stay well back from the water and listen to grown-ups.
Obey crocodile warning signs, keep well back from the water's edge and stay close to a grown-up.
Obey warning signs, stand at least 3 meters back from the edge when fishing, and never leave fish waste where people swim or moor boats.
Places where you might see it
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Watch
Country
Australia
Australia is a country and the smallest continent, surrounded by ocean in the Southern Hemisphere. Much of its middle is dry and flat, most people live near the coast, and its animals include kangaroos, koalas and the platypus, a mammal that lays eggs.
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Watch
Country
Indonesia
Indonesia is a country of about 17,500 islands in Southeast Asia, spread across the Equator between the Indian and Pacific oceans. It has more than 100 active volcanoes, rainforests full of wildlife, and about 286 million people (2025).
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Natural wonder
Kakadu National Park
Kakadu, in Australia's Northern Territory, is the country's largest national park. It stretches from a high sandstone cliff called the escarpment down to floodplains, mangroves and the sea. Aboriginal people have lived here for tens of thousands of years, and their rock paintings, some up to 20,000 years old, record their way of life.
Explore next
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Nile crocodile
The Nile crocodile is Africa's largest crocodile. It lives in rivers, lakes and swamps across much of eastern, central and southern Africa and Madagascar. It eats mostly fish, basks on sunny banks and is a surprisingly caring parent.
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Animal
American crocodile
The American crocodile is a large reptile of warm coasts and mangrove swamps, from the southern tip of Florida through Mexico, Central America, the Caribbean and northern South America. It is shy, it basks in the sun to warm up, and mother crocodiles carry their babies to the water.
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American alligator
The American alligator is a large, armored reptile of the swamps, marshes and lakes of the southeastern United States. Alligator mothers guard their nests and carry their babies to the water, and the holes alligators dig help many other animals survive dry seasons.
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Country
Australia
Australia is a country and the smallest continent, surrounded by ocean in the Southern Hemisphere. Much of its middle is dry and flat, most people live near the coast, and its animals include kangaroos, koalas and the platypus, a mammal that lays eggs.
-
Watch
Country
Indonesia
Indonesia is a country of about 17,500 islands in Southeast Asia, spread across the Equator between the Indian and Pacific oceans. It has more than 100 active volcanoes, rainforests full of wildlife, and about 286 million people (2025).
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Animal
Flatback sea turtle
The flatback sea turtle is named for its flat, smooth shell. It stays in shallow coastal seas around northern Australia, eats soft sea animals such as sea cucumbers and jellyfish, and nests only on Australian beaches, where its big hatchlings dash for the waves at night.
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Natural wonder
Kakadu National Park
Kakadu, in Australia's Northern Territory, is the country's largest national park. It stretches from a high sandstone cliff called the escarpment down to floodplains, mangroves and the sea. Aboriginal people have lived here for tens of thousands of years, and their rock paintings, some up to 20,000 years old, record their way of life.
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Animal
Gharial
The gharial is a crocodile relative with a long, skinny snout full of sharp teeth, perfect for snapping up fish. It lives in a few big rivers of northern India and Nepal, and it is one of the most threatened crocodilians on Earth.
For parents & teachers
What children will learn
- Describe what makes the saltwater crocodile the largest living reptile and how its body suits life in water.
- Explain what an estuary is and how this crocodile copes with both fresh and salt water.
- Describe the nest, temperature-dependent sex and the care females give their young.
- Explain how protection helped the species recover and how people stay safe in crocodile country.
Recommended ages: 3 to 17 · About 15 minutes
Talk about it
- Why might being able to live in seawater help an animal spread to so many islands?
- Why do you think moving a crocodile to another river does not stop it coming back?
- How can warning signs and education protect both people and crocodiles?
Try at home or in class
- Measure 5 meters with string in a hallway or yard to see how long a big saltwater crocodile is.
- Stir salt into a glass of water a spoonful at a time and taste a drop at each step (then spit it out) to feel how salty seawater is.
Key vocabulary: estuary, osteoderms, reptile, hatchling, billabong, homing
Where these facts come from
- The IUCN Red List of Threatened Species , International Union for Conservation of Nature (IUCN terms of use (no redistribution of Red List data or range maps))
- GBIF Backbone Taxonomy and GBIF Occurrence Search , Global Biodiversity Information Facility (CC0 1.0 (backbone); occurrence counts are facts derived from records under CC0, CC BY and CC BY-NC)
- Wikidata , Wikimedia Foundation (CC0 1.0)
- Crocodylus porosus (Saltwater Crocodile), Red List assessment 2019 , IUCN Red List of Threatened Species
- Estuarine crocodile , Australian Museum
- Crocodilian Species: Australian Saltwater Crocodile (Crocodylus porosus) , Crocodilians: Natural History and Conservation (Adam Britton)
- Wikimedia Commons , Wikimedia Foundation (Per file: Public domain, CC0, CC BY or CC BY-SA only (credited on each page))
Checked, not yet human-reviewed. Last updated October 27, 2026. Spotted a mistake? Tell us.