What is the world's largest reptile? It is a Saltwater Crocodile. These large animals can travel for thousands of kilometers in seawater and are native to many Indo Pacific areas.

Saltwater Crocodiles are found in brackish waters, where seawater meets freshwater. They can also exist in entirely saltwaters or entirely freshwaters. Usually juveniles feed on smaller animals like invertebrates, small reptiles, fish, or crustaceans. Adults take larger prey items and may eat animals as large as buffalo when fully grown. Saltwater Crocodiles hunt by waiting for prey to come near and then pounce upon it. Some larger prey items are dragged into the water to drown them. In captivity, caution should be used when keeping Saltwater Crocodiles. They get very large and are difficult to handle. Saltwater Crocodiles are not known to make docile pets as a general rule.

By maturity, Saltwater Crocodiles can reach between 20 and 23 feet (six to seven meters) in length. An average length for full-grown males is about 17 feet (five meters) and females rarely exceed ten feet (three meters). These crocodiles have massive heads with a pair of ridges running down the center of the snout between the eyes. The relatively short snout houses between 64 and 68 teeth. Usually adult Saltwater Crocodiles are brown or gray in color, though juveniles are often yellowish and some melanistic adult populations have been noted. The underside is generally whitish or creamy in color, although the underside of the tail tip is often gray. Usually darker colored bands or stripes mark the flanks. The scales are more oval than those of many crocodile species and the back feet of Saltwater Crocodiles are webbed.

Nicknamed Salties, Saltwater Crocodiles are native to many estuarine Indo Pacific regions. For this reason they are also known as Estuarine Crocodiles. Some have traveled thousands of kilometers in the ocean and have been found with barnacles on their scales. This incredible voyaging ability probably explains why Saltwater Crocodiles are found throughout most of Asia, Indian Ocean, and Pacific Ocean locales. They range from China all the way south through Australia, though they are rarely found far west or east of this long corridor. Though Saltwater Crocodiles were once found on the Seychelles Islands, they are now extinct there. They are listed internationally as a low risk species, tending to be more endangered in some areas than others. Over hunting for their valuable skins has depleted Saltwater Crocodile populations, though they have recovered somewhat through extensive conservation and captive breeding programs. Illegal poaching continues to remain a major problem.

Captive Saltwater Crocodiles are usually fed whole prey items. Hatchlings and growing young are often fed diets based on small pieces of poultry or red meat. Saltwater Crocodiles require plenty of space and a semi-aquatic environment. Although hatchlings are usually kept indoors, by the time they are about one year old, they should be placed outside in areas consisting of shallow water and land. The ponds should be between 150 and 300 millimeters deep, and after the Saltwater Crocodile is four years old, it can be kept in deeper pools. Male-female pairs may get along, although ratios of one male to several females are generally recommended.

Saltwater Crocodiles breed in freshwater areas. By the time females are about two and a fifth meters long, they are sexually mature, though males do not reach sexual maturity until they are about a meter larger than this. Between November and March, raised nests are constructed. Into these nests between 25 and 90 eggs will be deposited. The average clutch contains about 50 eggs. Females will remain near the nests, although many Saltwater Crocodile eggs are drowned in floods or stolen by animals or humans. At appropriate temperatures, the eggs require about 90 days to hatch. Males will be produced when the temperature remains at 31.6 degrees Celsius. Captive bred eggs are usually incubated at 32 degrees Celsius and require 77 days to hatch. When the female hears the young begin to hatch, she will assist them in emerging and will carry them in her mouth to the water. Probably less than one percent of these hatchlings will reach adult hood. Those in areas inhabited by adults may be driven out or killed, and other animals prey upon many hatchlings.