Australian freshwater crocodile, Johnstone's crocodile, Freshie
The Freshwater crocodile (Crocodylus johnsoni) is a species of crocodile found only in the northern regions of Australia. Unlike their much larger Australian relative, the Saltwater crocodile, Freshwater crocodiles are not known as man-eaters, although they bite in self-defense, and brief, nonfatal attacks have occurred, apparently the result of mistaken identity.
The Freshwater crocodile is a relatively small crocodilian. This species is shy and has a slenderer snout and slightly smaller teeth than the dangerous saltwater crocodile. The body color is light brown with darker bands on the body and tail - these tend to be broken up near the neck. Some individuals possess distinct bands or speckling on the snout. Body scales are relatively large, with wide, close-knit, armored plates on the back. Rounded, pebbly scales cover the flanks and outsides of the legs.
The freshwater crocodile is an Australian reptile. The species inhabits rivers, creeks, freshwater wetlands, swamps, and billabongs of Western Australia, Queensland, and the Northern Territory.
These reptiles are night hunters, meanwhile being active by day. Freshwater crocodiles use the so-called "sit-and-wait" technique of hunting, unexpectedly attacking the prey by quick sideways motion of the head. Those, living in areas with constant availability of water, are active throughout the year. In the meantime, those, exposed to drought during the dry winter season, tend to become dormant. During the winter, the crocodiles find shelter in dens, dug into the creek bank, where a group of these animals can be seen using the same den. Freshwater crocodiles, living in captivity, are not tolerant of their own kind, often showing extremely aggressive behavior towards one another. Those, living in the wild, are typically dominated by a large male, who tends to attack and bite the tails of lower-ranked crocodiles, thus establishing dominance. When threatened on land, the reptile quickly flees by fast galloping, entering into the water, where the animal feels safe.
Adult freshwater crocodiles are carnivores, they usually feed upon reptiles, amphibians, insects, bats, crustaceans, and fish as well as occasional land mammals, caught in nearby water. Meanwhile, juveniles tend to consume smaller prey such as insects, crustaceans, and smaller species of fish.
Freshwater crocodiles have a polygynous mating system, where each male mates with more than one female. About 3-6 weeks after mating, typically between August and September, the female digs a nest: she chooses a place along the river bank and digs a hole in a sand embankment. She usually lays the eggs at night. The amount of eggs per clutch varies from 13 to 20. As the offspring hatch out (in about 65-95 days), the female carries them to the water in its mouth. Over a short period of time, the female remains with the young, protecting and caring for them, after which she leaves her offspring on their own. Male freshwater crocodiles reach reproductive maturity at 16-17 years old, whereas females - a little bit earlier - at 11-14 years of age.
The primary threat to these crocodiles is habitat destruction due to agricultural development. Freshwater crocodiles also suffer from illegal hunting, which significantly decreases the population of this species.
The IUCN Red List and other sources don’t provide the number of the Freshwater crocodile total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
These reptiles form an important link in the food chain of freshwater and estuarine ecosystems of their habitat. Thus, they are top predators of their range, consuming a variety of animal species. On the other hand, their hatchlings and juveniles become prey for other animals in the area, including goannas, barramundi, feral pigs, sea eagles, turtles as well as other crocodiles. This makes Freshwater crocodile both predator and prey, due to which the animal helps keep a wetland ecosystem healthy, which, in turn, maintains the fishery healthy.