Facts About Saltwater Crocodiles

You think dinosaurs are extinct? Well, you haven’t met a saltwater crocodile. These blokes are as old as the earth — all scales, snouts and serious bite force. I still remember the first time I saw a big male slide into a billabong up near Cahills Crossing. If you’re curious, here are some facts about saltwater crocodiles: Saltwater crocodiles (Crocodylus porosus), also known as estuarine crocodiles, are the largest living reptiles on the planet. Found across Northern Australia, Southeast Asia and as far west as India, these big buggers have been ruling the waterways for millions of years. But don’t let the name fool you — they’re not just beach bums. Salties are just as happy in freshwater rivers, brackish mangrove swamps and coastal waters.

Crocodile Habitat

Despite the name, salties aren’t fussy about water type. They’ll cruise through freshwater rivers, billabongs, swamps, river deltas and even the open sea. That last one stumps a lot of people — but yep, saltwater crocs are pretty good swimmers and can travel hundreds of kilometres.
In Australia you’ll find them across the tropical north: from Broome in Western Australia to Rockhampton in Queensland. Some of the best-known croc countries include:

Kakadu National Park (NT)
Mary and Daly Rivers (NT)
Bhitarkanika Wildlife Sanctuary (India)
Daintree River (QLD)
Kimberley coast (WA)
Cape York Peninsula (QLD)

Always follow the signs and assume any water in these regions could have a croc. Don’t risk it for a quick dip.

As Old as Dino

Saltwater crocodiles (or ‘salties’ if you’re local) are some of the oldest living reptiles on the planet. We’re talking 200 million years of evolutionary resilience — they’ve been cruising rivers and coastal waters since before the T. rex roamed the earth. These estuarine crocodiles have outlasted ice ages, shifting continents and the odd asteroid. So when you see one lounging in a brackish mangrove swamp, just know you’re looking at a living fossil with a mean mug and a stronger bite than a great white.

The Biggest Reptiles in the World

If you’re after record-holders, the saltwater crocodile doesn’t disappoint. Adult males can grow over 6 metres long and weigh over 1,000 kilograms — an incredible example of body size and sexual size dimorphism. That’s heavier than a Hilux ute and twice as long. The biggest verified saltie? Lolong — 6.17 metres, caught in the Philippines. But Aussie crocs aren’t far behind — especially in the Northern Territory’s Daly River and East Alligator River regions, and across croc country in Western Australia and Northern Australia.

READ Crocodiles in the Northern Territory

Crocodiles Lay Eggs

Female saltwater crocodiles don’t mess around when it comes to parenting. They lay around 40 to 60 eggs in mounded nests during the wet season — usually November to March. The temperature of these nests even determines the sex of the hatchlings. And unlike many other crocodile species, she’ll fiercely guard that nest from natural predators, including wild boar, goannas and nosey humans. Don’t be the tourist who gets between a female saltwater crocodile and her eggs.

The Strongest Bite on Earth

Salties have the strongest bite of any living animal — up to 3,700 PSI (pounds per square inch). This incredible bite is part of their unique animal physiology and is the strongest bite in the animal kingdom. It’s not just brute force either — that bite comes with 60+ conical teeth designed for gripping slippery prey like fish, birds and the odd wallaby. The bite force quotient of salties is off the charts, way above all other crocodilian bite forces.

They Can’t Sweat

Like most reptiles, saltwater crocodiles can’t sweat. To cool down, they’ll hang around in fresh water or bask with their mouths open — known as “gaping”. It’s a croc’s way of thermoregulating. If you see one sunbaking with its jaws open, it’s not threatening you (yet) — it’s just trying not to overheat.

Top of the Food Chain

Saltwater crocodiles are apex predators. Once they reach sexual maturity and adult size range, they’ve got no natural predators — except humans, and even then, we tread lightly. Their diet? Anything they can catch, which includes fish, birds, turtles, feral pigs, buffalo, dingoes, wild boar, and even sharks. They’re among the deadliest ambush predators in both saltwater and freshwater rivers.

They Can Only Eat Above Ground

Crocs might be kings of the water, but they can’t eat underwater — they’ve got a special valve in their throat that stops water from flooding their lungs. So once they catch something, they need to surface or drag it ashore to eat. That’s where the infamous “death roll” comes in — they’ll spin their body to tear off chunks, especially if the prey’s a bit on the large side. This is a primary behaviour associated with feeding.

Faster than Speedy Gonzales

Despite their bulky build, salties can move surprisingly fast on land in short bursts — up to 12–14 km/h in a gallop. That’s not marathon pace, but it’s enough to ruin your picnic if you’re not paying attention. In water? Even faster — up to 30 km/h in short ambush lunges using their powerful tails.

Marathoners — Not Just Sprinters

While they’re not built for long land chases, saltwater crocodiles can travel hundreds of kilometres by sea. They ride ocean currents, estuaries and river deltas with GPS-worthy precision. Juvenile crocodiles have even been tracked crossing entire gulfs. This current-riding behaviour helps crocs conserve energy and explains why they show up in places you didn’t expect.

READ Crocodile Farm

Temperatures Determine Their Gender

The sex of baby crocs is determined by the temperature inside the nest. Warmer nests (around 31.6°C) produce males, cooler or hotter temps produce females. This temperature-sex link is crucial for population health. That’s why changing water levels and climate is a concern — it can skew sex ratios in wild saltwater crocodile populations. .

Protected Animals

Back in the day (pre-1970s) saltwater crocodiles were nearly hunted to extinction for their skins — a big chapter in the history of wildlife trade and unregulated hunting. Since protections were introduced — first in Queensland (1974), then the NT (1971), and WA (1970) — populations have recovered, especially under the Northern Territory Government’s conservation efforts. Today they are managed through programs like the Assessment of Saltwater Crocodile Populations.

Camouflage

A salties‘ rough, mottled skin isn’t just for show. It’s brilliant camouflage in murky water and mangrove shadows. Add to that a low floating posture and just the eyes and nostrils above water and you have a stealth machine. They’ll often lie still for hours waiting for the perfect ambush moment — true to their role as ambush predators.

Sleep with One Eye Open (Literally)

These prehistoric lizards have a party trick — unihemispheric sleep. That means one half of their brain can sleep while the other stays alert. They’ve been seen resting with one eye open especially when surrounded by threats or during agonistic behaviour (like territory disputes). Handy for guarding nests — or just being croc-level paranoid.

Baby Crocs and the Long Crawl to Survival

Only 1% of hatchlings survive to adulthood. Between goannas, birds, fish and bigger crocs it’s a tough world out there for a baby croc. Those that make it? Tough as nails. Mums will often carry their young to water in their mouths — and can recognise their baby’s distress calls weeks after hatching. That journey from egg to adult crocodile in captivity or the wild is no easy feat.Get ready for an unforgettable experience on our crocodile tours from Darwin, where you can see these incredible creatures in action.

“Death Roll” Move

Yes, the death roll — the stuff of nightmares and wildlife docos. When a croc grabs prey too big to swallow whole, it spins with terrifying force to rip it apart. It’s brutal, efficient and uniquely crocodilian. You’ll see it in action if you ever watch croc feeding time at a park like Crocodylus Park near Darwin or observe behaviour at a Wildlife Sanctuary like Bhitarkanika Wildlife Sanctuary.

READ Things to do around Darwin