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THE ESTUARINE OR AUSTRALIAN SALTWATER CROCODILE

COMMON NAMES:
Australian Saltwater Crocodile, Estuarine Crocodile, 'Saltie', Indo-Pacific Crocodile

DISTRIBUTION:
Australia, Bangladesh, Brunei, Myanmar (Burma), Cambodia, China, India (including Andaman Islands), Indonesia, Malaysia, Palau (Caroline Islands) , Papua New Guinea, Philippines, Singapore, Sri Lanka, Solomon Islands, Thailand, Vanuatu (Banks Islands), Vietnam. Some ‘Salties’ have been found to travel some distance from their usual range (e.g. Japan, islands in the Indian Ocean). They can travel long distances (over a thousand km) by sea - barnacles have been found on the scales of a few stray individuals. This sea-faring ability probably helps to explain their wide distribution.

HABITAT:
As their name suggests, this species has a high tolerance for salinity, being found in brackish water around coastal areas and in rivers. However, it is also present in freshwater rivers, billabongs and swamps. Subordinate animals unable to establish a territory in a tidal river system are either killed or forced out into the sea by their elders, where they move around the coast in search of another river system.

STATUS:
IUCN-International Union of Conservation of Nature (Least Concern)
Estimated wild population: 200,000 to 300,000

APPEARANCE:
The saltwater crocodile is the largest living crocodilian species based on confirmed measurements. It is also the world's largest living reptile in terms of mass. Adult males can reach sizes of up to 20 feet. However, the largest confirmed individual was measured as 20.7 feet taking into account a piece missing from his tail! Females are smaller, the normal maximum adult size being 8 to 10 feet. Maximum weight varies, but large salties have been known to exceed 1,000 kg as 18 to 19 foot adults. This is a large-headed species with a heavy set of jaws. A pair of ridges run from the eye orbits along the centre of the snout, becoming more distinct with age. Ostioderms are restricted to the back and a small cluster on the neck. Juveniles are normally pale tan in colour with black stripes and spots on the body and tail. Mature adults are generally dark, with lighter tan or grey areas.

DIET:
Saltwater crocodiles have a big appetite and consume a large quantity of prey, although juveniles are restricted to smaller items such as insects, amphibians, crustaceans, small reptiles and fish. Prey items include crustaceans (e.g. mudcrabs) and vertebrates (e.g. turtles, goannas/lizards, snakes, shore and wading birds). Large adults occasionally take much larger prey include buffalo and domestic livestock, wallabies, wild boar, monkeys etc.

BREEDING:
Breeding territories are usually established along tidal rivers, creeks and freshwater areas. Females reach sexual maturity at lengths of 6-7ft (10 to 12 years old). Males mature later around 9ft, and around 16 years old. Females on average lay 40 to 60 eggs (this can range from 25 to 90) in mound nests made from vegetation (usually grasses and vines) and mud. These are normally constructed between the months of November and March during the wet season, but this varies slightly geographically. The mound helps to insulate the eggs from temperature extremes, hides them from predators, stops them from dehydrating, and also serves to raise the eggs above the ground to minimise the risk of flooding. Although the female stays near the nest, eggs do occasionally fall foul of predators (e.g. monitor lizards, feral wild pigs in Australia) and human egg collectors.

CONSERVATION:
Many species of crocodilians are falsely viewed as man-eaters, but fear of this species is not unfounded, with a number of people injured or killed each year, although in most cases these tragedies are usually human error. However, loss of life has led to a degree of antipathy towards the species, making conservation measures more difficult to implement.

Australia has been the centre for most of the extensive research carried out on this species, and several model breeding and conservation programs exist there. It is estimated that there are at least 100,000 to 150,000 crocodiles in the northern three states of Australia (Western Australia, Queensland and Northern Territory where the largest population base exists). Sustainable use programs have been implemented in the Northern Territory, and have proven to be highly successful in giving people an incentive to preserve not only the crocodiles but more importantly the habitat which supports them. The future of the species seems to be very secure at the moment, given the large population bases in Australia and Papau New Guinea.