Freshwater crocodile facts, pictures and information. Discover the smaller of Australia’s two crocodile species …
Freshwater Crocodile Facts at a Glance
- Other Name(s): Australian freshwater crocodile, Johnstone’s crocodile, Johnstone’s river crocodile, fish crocodile, ‘freshie’
- Scientific name: Crocodylus johnstoni (or johnsoni)
- Type of Animal: Reptile
- Animal Family: Crocodylidae
- Where Found: Northern Australia
- Length: males 3 to 3 m (7.5 to 9.8 ft.); females up to 2.1 m (6.9 ft.)
- Average Weight: males 70 kg (150 lb.); females 40 kg (88 lb.)
- Conservation Status: Least Concern
Other interesting freshwater crocodile facts …
- The freshwater crocodile is endemic to (i.e. only found in) northern mainland Australia.
- The freshwater crocodile is the smaller of the two crocodile species found in Australia. (The other species is the mighty saltwater crocodile, which is not only the world’s largest crocodile, but also the world’s largest reptile!)
- The freshwater crocodile isn’t considered deadly, and some people even swim in areas inhabited by the species. However, if threatened, the freshwater crocodile can deliver a nasty bite.
- The freshwater crocodile can stay submerged for over an hour by slowing its heartbeat down to a few beats per hour.
The freshwater crocodile is a relatively small, slender crocodile. The largest individuals reach lengths of around 3 m (10 ft.). The tail makes up nearly half of the freshwater crocodile’s length. The hind limbs are bigger than the forelimbs.
The freshwater crocodile is gray to green-brown in color. The back and tail are marked with darker bands and patches. The undersides are creamy white.
The freshwater crocodile’s scales are large and do not overlap. Bony plates called ‘scutes’ embedded in the skin of the crocodile’s back and tail provide additional protection.
You can see awesome footage of freshwater crocodiles in the video below:
As with all crocodilians, the freshwater crocodile’s eyes and nostrils are located at the top of the head. This allows it to remain almost completely submerged while still being able to breathe and to keep an eye on its surroundings.
The freshwater crocodile has 68 to 72 teeth.
In addition to its smaller size and slender build, the freshwater crocodile can be distinguished from the saltwater crocodile by its significantly narrower snout and smaller teeth.
Populations of ‘pygmy’ freshwater crocodiles exist in the Northern Territory (a large region of northern Australia). The members of these populations rarely exceed 1.5 m (5 ft.) in length. However, there is no evidence to suggest that they are a different species to ‘full size’ freshwater crocodiles.
Freshwater Crocodile Facts: Where Found
The freshwater crocodile is only found in northern mainland Australia. It is present in the states of Western Australia and Queensland, and in the Northern Territory.
You can see these areas on the map below:
Freshwater Crocodile Habitat
The freshwater crocodile may be present in almost any permanent body of freshwater, including rivers, streams, creeks, swamps, floodplain lakes and lagoons.
The species is most commonly found inland in arid, rocky areas. It may also be present in brackish waters in coastal regions. (Brackish water is a mixture of salt and fresh water.)
During the wet season the freshwater crocodile often disperses into flood plains (the low-lying areas either side of a river). During the dry season freshwater crocodiles tend to congregate in deeper bodies of water.
Freshwater Crocodile Behavior
Crocodiles resident in areas with permanent bodies of water tend to stay active throughout the year. Those found in areas that experience dry seasons spend those times in a dormant state, sheltering in holes dug into river banks.
The freshwater crocodile is known to walk long distances while searching for a suitable dry season refuge. Individuals often return to the same sites year after year.
The freshwater crocodile is generally shy and wary of humans. If startled, it is most likely to flee rapidly to the safety of the water. It may also respond to threats either by growling, or by inflating its body and making ripples in the water by shuddering.
Freshwater Crocodile Life Cycle
Unlike its saltwater relative, the freshwater crocodile mates during the dry season. In captivity, a courtship behavior that involves the male placing its head on that of a female and rubbing her with the glands underneath his throat has been observed.
The female lays her eggs around 6 weeks after mating, usually in August or September. Using her hind limbs, she digs a hole into the sand about 10 m (33 ft.) from the water’s edge, usually at night.
Into this nest the female will lay a clutch of between 4 and 20 hard-shelled eggs. Large females typically lay a larger number of eggs.
Incubation takes from 2 to 3 months. The hatchlings usually emerge at the beginning of the wet season (November to December).
The young begin to call from their eggs about 1 to 5 days before hatching. Adult females respond to these calls by digging the nests open. They may also even help the infants break out of the eggs.
The adult female then picks up the hatchlings one by one in her mouth and carries them into the water. It is not known whether or not the adult female attending to the hatchlings is actually the mother of the hatchlings.
What Do Freshwater Crocodiles Eat?
The freshwater crocodile eats a wide variety of invertebrates and vertebrates. Various insects (both aquatic and terrestrial) and fish usually make up a large part of the reptile’s diet.
Other prey animals include turtles, lizards, snakes, frogs, crustaceans, spiders, birds and small mammals (such as bats and rats). Large individuals are able to take down larger prey animals such as wallabies.
The crocodile uses a ‘sit-and-wait’ method to capture small prey: lying in shallow water, it waits until the prey comes within striking distance before grasping the animal using a quick sideways motion of its head. The crocodile catches larger prey by stalking and ambushing.
Mature freshwater crocodiles have few predators but can be targeted by saltwater crocodiles in areas where both species are present.
Freshwater crocodile eggs are frequently eaten by goannas. (These large lizards may consume up to 90% of freshwater crocodile eggs in some areas). The eggs are also eaten by dingoes, feral pigs and feral dogs.
The hatchlings are vulnerable to predation by larger crocodiles, freshwater turtles, birds of prey, large fish and pythons. Few young survive their first year of life.
Is The Freshwater Crocodile Dangerous To Humans?
Unlike the larger and more aggressive saltwater crocodile, the freshwater crocodile will usually flee from humans and is not considered particularly dangerous. However, the animal is capable of giving a nasty bite with its sharp teeth if provoked.
Is The Freshwater Crocodile Endangered?
The freshwater crocodile is rated ‘Least Concern’ by the IUCN. The species is widely distributed, and there are no major threats likely to impact upon the population as a whole.
Some sub-populations have declined due to the presence of the cane toad (Rhinella marina), an introduced species whose skin produces poisonous secretions.
Although large crocodiles can tolerate the toad’s toxin, small and medium-sized individuals frequently die after eating the toad.
The cane toad is also poisonous to the goannas that prey on freshwater crocodile eggs. In some areas the toad’s presence has led to an increase in the number of crocodile hatchlings.