Snappy facts: everything you wanted to know about crocodiles in Queensland
Issued: 25 Jun 8 min read

Crocodiles are some of Queensland’s oldest residents – learn a little more about these fascinating creatures (and how to coexist with them safely).

Whether they fascinate or terrify you (or maybe a little of each), there’s no denying that crocodiles are divisive creatures. Like most dangerous animals, much of the fear surrounding crocs comes from knowledge gaps and misinformation. Once you learn about the fascinating physiology and behaviour of these ancient reptiles, you can gain a new understanding of the vital role they play in Queensland’s ecosystem.

We’re here to shed some light on one of Queensland’s most misunderstood residents, as well as provide some practical tips for coexisting safely with crocs.

(left photo) A freshwater crocodile sitting in shallow water raises its snout. (right photo): Close-up of a saltwater crocodile’s face showing its teeth.

Face-off: Apart from their size difference, the snout is the biggest visual clue to tell a freshwater crocodile (left) from a saltwater crocodile (right).

What types of crocodiles are found in Queensland?

When people talk about Queensland’s croc population, odds are they’re referring to the estuarine crocodile (also known as the saltwater crocodile). However, our state also has “freshies” – yep, freshwater crocodiles can also be found in Queensland’s temperate northern waters.

What’s the difference between saltwater and freshwater crocodiles?

At first glance, freshwater and saltwater crocodiles seem quite similar – but when you dive a little deeper, there are some key differences between these two distinct species. Check out the table below for a quick guide to telling these reptilian relatives apart.

Feature	Saltwater/estuarine crocodiles	Freshwater crocodiles
Size	Males: Average between 3–4 metres long, weighing around 200–300 kilograms. Females: 2.5–3 metres long, weighing up to 150 kilograms.	Males: Up to 3 metres long, weighing up to 60 kilograms. Females: Around 2 metres long, weighing up to 30 kilograms.
Habitat	Both saltwater and freshwater environments; coastal areas, estuaries, rivers, swamps, and can venture out to sea.	Primarily freshwater habitats; rivers, lakes, billabongs; rarely brackish or saltwater.
What they look like	Broader snout, robust build, irregularly sized rounded teeth. Colours range from almost black through to grey and olive-brown, with ragged, dark mottling.	Narrower, longer snout, slender body, evenly shaped and sized needle-like teeth. They have grey or olive-brown colouring with ragged dark mottling.
Distribution in Queensland	Northern regions, including along the coast and in major river systems.	Northern parts, more restricted to freshwater environments away from coastal areas.

Are crocodiles aggressive?

Both estuarine crocodiles and freshwater crocodiles are ambush predators that wait for their prey to visit the water’s edge – from here, they can grab their meal with their powerful jaws.

Due to their size and their territorial, opportunistic nature, saltwater crocodiles are considered an aggressive species. Basically, once these crocs reach adult size, any creature they can overpower is fair game. If a human encroaches on a saltwater croc’s territory, the croc may decide to attack.

On the other hand, freshwater crocodiles are generally shy and quick to flee from humans. That said, if you disturb them in their habitat and they feel cornered, they’ll likely get defensive and bite. While freshies are relatively chill compared to their estuarian counterparts, you should still regard them with caution and avoid approaching them in the water.

Photo of an estuarine crocodile on the shores of Pelican Island holding a pomarine jaeger in its jaws.

This estuarine crocodile is dining on a pomarine jaeger, an arctic migratory bird.

What do crocodiles eat?

Young saltwater crocodiles are born hunters – they dine on small insects, crabs, prawns and shrimps as soon as they hatch! When estuarine crocs hit the two-metre mark, their diet expands to bigger vertebrates like fish, frogs, birds, water snakes, and rats. Full-grown adults virtually have a buffet at their disposal – they can overpower sea turtles, goannas, wallabies, feral cats and pigs, dogs, kangaroos, cattle, horses, buffalo, and even other crocodiles.

Conversely, freshwater crocodiles don’t have such large targets. Their diet is mostly small animals including insects, fish, frogs, lizards, turtles, bats, and birds. If the timing is right, they may also snatch small mammals from the water’s edge.

Graphic outline of a map of Queensland with crocodile habitats coloured in green and the text “Croc Country” overlaid.

This map of Queensland shows typical known crocodile habitats.

Where do crocodiles live?

While there are no hard and fast borders, the typical crocodile habitat in Queensland begins at the Boyne River south of Gladstone, extending northward up the east coast and across far north and northwest Queensland to the Northern Territory border.

Crocodiles take up residence in freshwater and saltwater locations along the coast, as well as up to hundreds of kilometres inland. You’re liable to find these snappy subjects hanging out in:

rivers and creeks (including tidal reaches and mouths)
swamps
lagoons
waterholes
beaches
oceans
offshore islands of the Great Barrier Reef and Torres Strait.

Don’t let the name fool you – saltwater crocodiles can also live in freshwater (they just prefer saltwater environments because they boast more food sources).

A group of estuarine crocodiles congregate on a riverbank.

Estuarine crocodiles become very mobile (and visible) during breeding season.

Photo credit: Tourism and Events Queensland

Crocodile breeding

The differences between how salties and freshies breed have an impact on their overall numbers in Queensland, with estuarine crocs outnumbering their freshwater counterparts quite significantly.

Male estuarine crocodiles reach sexual maturity at around 17, while females mature at about 12. Courtship starts in October/November, with nesting occurring from December to April – and the male crocs become especially sassy when looking for a mate. Females build mounds of vegetation and soil near water to keep their eggs above flood levels, with the mother guarding the nest from predators and helping the young in hatching. The hatchlings hang out in “croc creche” with their mums for up to five weeks before dispersing.

In contrast, freshwater crocodiles are late bloomers, with males and females reaching maturity at around 15–20 years. Their breeding season starts in July/August, with nesting confined to a short period from August to September – this shorter timeframe is called pulse nesting. Freshwater crocodiles lay fewer eggs in simple holes near the water. Unlike salties, they aren’t as vigilant with their eggs, leading to a high rate of egg predation and flooding – and this means only about 12% of hatchlings survive their first year.

Q&A: Fun crocodile facts

Are crocodiles dinosaurs?

While crocodiles are not technically dinosaurs, they are distantly related to them through a group known as archosaurs (or “ruling reptiles”). This group dates back to the Early Triassic Period – we’re talking 250 million years ago!

Are crocodiles endangered?

Good news – Queensland’s two main crocodile species are protected. Both saltwater and freshwater crocodiles in the Sunshine State have healthy populations, with our estuarine mates listed as a vulnerable species under the Nature Conservation Act 1992.

Can crocodiles breathe underwater?

Nope – crocodiles have lungs, not gills. Large saltwater crocs can slow their heart rate to 2–3 beats per minute, meaning they can lurk underwater for at least an hour – an ideal characteristic for these ambush predators.

How long do crocodiles live?

Estuarine and freshwater crocodiles are believed to live for over 50 years in the wild – not a bad innings!

An estuarine crocodile resting on a muddy surface by the edge of a body of water, partially obscured by foliage.

A genetic study of Queensland’s estuarine crocodiles has changed what scientists know about these fascinating creatures.

How crocodile gene studies are keeping humans safe

One of the most divisive issues surrounding crocodiles in Queensland is how they are managed and monitored. In 2024, a massive long-range genetic study of Queensland’s estuarine crocodiles has revealed some fascinating facts about the species’ behaviour – and these critical insights are crucial to crocodile management in the state.

A collaboration between the Department of Environment, Science and Innovation (DESI) and CSIRO, this study has unlocked major mysteries around crocodile movement in Queensland. This data on where crocs come from, where they go, and how far they travel can help improve croc conservation and public safety.

Be Crocwise 00:43
Important safety information about crocodiles.
Important safety information about crocodiles.

Stay safe and Be Crocwise

Crocodiles are a natural part of our Queensland landscape – so it’s vital to act responsibly in areas where they hang out. Being Crocwise in Croc Country is all about understanding common croc behaviours and reducing your risk of unfriendly croc encounters. Here are some quick tips.

Know when crocs are most active

Crocodiles are very stealthy creatures that use ambush tactics to capture prey. These amazing creatures can stay underwater and remain completely concealed for up to an hour – even in knee-deep water! Long story short, just because you can’t see a croc doesn’t mean you’re in the clear.

Crocodiles are most active at night, dusk, and dawn. They are also very mobile during and after high tides and heavy rains, so it’s vital to be extra vigilant during these periods.

Five golden rules to reduce your risk in Croc Country

Stay at least 5m from the water’s edge – if you must move closer, try to have a sturdy object like an Esky, tree, or large rock between you and the water
Dispose of your food and fish scraps in a bin (or take them home)
Keep pets on a lead and away from the water’s edge
Avoid using small watercraft like kayaks and paddleboards
Stay well away from crocodile traps.