Saltwater crocodiles – NT Government

The Saltwater Crocodile (Crocodylus porosus) is one of two species of crocodile found in Australia; the other being the smaller Freshwater Crocodile (Crocodylus johnstoni). Subspecies or races have not been described.

Top End waterways are some of the best remaining habitats for saltwater crocodiles in the world. There is estimated to be over 100,000 saltwater crocodiles in the NT at the moment.

Alarge proportion of the coastal region of the Northern Territory is an idealhabitat for saltwater crocodiles, particularly the big, productive “coastal”wetlands and rivers. Much of the Queensland coastline is in the cooler, moresoutherly latitudes, which is less optimal habitat for crocodiles. Much of thehabitat on the east coast has also been significantly altered and fragmented byhuman settlement. Western Australia has saltwater crocodile habitat around theKimberley coastline but this area is not as rich in mangroves and wetlands asthe Territory coastline.

Inthe southern part of its range, winter temperatures reach a threshold belowwhich crocodile eggs will not hatch and the longer cold periods significantlylower crocodile growth rates. The effect of a cooler climate on crocodiles canbe seen in those animals kept in wildlife parks in southern Queensland. Thecrocodiles do not feed over winter as they cannot absorb enough warmth todigest food.

Howold is the crocodile

Crocodileshave been around for 200 million years, and are a descendant from the dinosaurage.

Whatis the full taxonomic name for the saltwater crocodile?

Whatare the physical features of the crocodile

TheAustralian saltwater crocodile is one of the most aggressive and dangerouscrocodiles. It is also the largest living reptile, exceeding the Komodo dragonin size. Sexual dimorphism (difference) is present in this species, with thefemales normally growing to more than 3 metres and males normally up to 6metres. Crocodiles up to 10 metres have been recorded in the wild in the past,but are extremely rare.

Saltwatercrocodiles have very large heads. A pair of ridges runs from the eyes along thecentre of the snout. The eyes, ears and nostrils are located on the same planeon the top of the head, allowing it to see, hear and breathe while almosttotally submerged. The eyes have a special second pair of eyelids known as thenictitating membrane. These eyelids are clear and protect the eyes while underwater.The ears, situated behind the eyes, have flaps which also close whileunderwater. The jaws are heavyset and contain 64-68 teeth. The teeth in theupper jaw are perfectly aligned with those in the lower jaw. The fourth toothon each side of the bottom jaw is larger than the other teeth and is visiblewhen the mouth is closed.

Whatis the habitat and distribution of the saltwater crocodile?

Thesaltwater crocodile is a mostly aquatic animal that spends little time on dryland. Saltwater crocodiles inhabit coastal rivers and wetlands, the open seaand island shorelines, and extend well inland via major rivers and floodplainbillabongs into freshwater rivers, creeks and swamps.

Theyare distributed widely in the Asia-Pacific region, including Australia, PapuaNew Guinea, Indonesia, Timor Leste, Malaysia, Myanmar, Sri Lanka, Philippines,Singapore, India, Bangladesh, Vietnam, Thailand, Solomon Islands and variousother islands in both the Pacific and Indian Oceans. They are locally extinctfrom the Seychelles islands.

InAustralia, saltwater crocodiles occur in high densities in freshwater wetlands,floodplains and in the tidal portions of some mangrove-lined rivers. Saltwatercrocodiles may occur in any salt or fresh water within their range. Large malesaltwater crocodiles are known to defend their area and females defend theirnest from predators.

Distributionof saltwater crocodiles in the Northern Territory

WithinAustralia, there are two species of (true) crocodiles: the saltwater (orestuarine crocodile) and the endemic Australian freshwater crocodile. Saltwatercrocodiles are found in both tidal and freshwater areas. Saltwater crocodilesare naturally found long distances upstream into areas dominated by, andconsidered typical for fresh water crocodiles. Fresh water crocodiles are onlysometimes found in tidal, saline areas. Within the Northern Territory,freshwater crocodiles were protected in 1963 and saltwater crocodiles wereprotected in 1971.

Whatdo saltwater crocodiles eat

Thesize of the saltwater crocodile prey is only limited by the crocodiles own sizeand strength. Saltwater crocodiles mostly eat fish, but will eat almostanything that they can overpower which can include turtles, goannas, snakes,birds, livestock (cattle), buffalo, wild boar and mud crabs. Hatchlings andjuvenile crocodiles feed on insects, crustaceans, small reptiles, frogs andsmall fish.

Dosaltwater crocodiles have enemies

Saltwatercrocodiles were once hunted extensively in Australia by humans for their skinwhich is considered internationally to be the best hide from the world’scrocodile species. In many countries, including Australia, hunting is nowillegal, yet around the world there is still some illegal poaching. In someparts of the world they have been almost hunted to extinction, due to the valueof their hide, habitat clearing and their reputation as man-eaters.

Humansaren't the crocodiles’ only threat. Feral buffalo destroy nesting habitats andgoannas can dig out eggs from nests. Hatchlings or juveniles can be eaten bybarramundi, turtles, freshwater crocodiles and older saltwater crocodiles.

Additionalthreats to the long term survival of the crocodile include habitat modificationand encroaching human populations and the possibility of climate change inducedsea level rises altering suitable habitats.

Whendo saltwater crocodiles breed

Saltwatercrocodiles reach sexual maturity at 10-12 years for females and males at 16years. Females build mound nests from vegetation between November and May, andan average of 50 eggs are laid. If the nest is around 31.6°C, all the eggs willhatch as males. Above 33°C or below 31°C the crocodile eggs will hatch asfemales. The eggs hatch from 75 days. Only 1% of the hatchlings are thought tosurvive to maturity in the wild.

Howfast do crocodiles grow

Saltwatercrocodile eggs vary in size. The average saltwater crocodile egg weighs 113grams and the average hatchling weighs 72 grams at a total length of 29.3 cm;their head length is 4.3 cm and snout to cloaca length is 13.8 cm.

Femalesusually reach maturity when around 2.3 metres in length. Males mature at around3.3 metres. Farmed crocodiles grow faster and mature earlier that those in thewild.

Whatare some other common crocodile names

EstuarineCrocodile, Saltie, Croc, Indo-Pacific Crocodile, Singapore Small Grain, Baya,Buaja, Buaya maura, Gator.

Saltwater crocodiles – NT Government – Be crocwise (2024)