In captivity, unlike the soft shelled turtles of the family Trionychidae, pig-nosed turtles retain a domed bony carapace beneath their leathery skin, rather than a flat plate. They also retain a solid plastron, connected to the carapace by a strong bony bridge, rather than the soft margin of the trionychids.
Pig-nosed turtles are not completely aquatic. Little is known about general behaviour, as there have been few studies in the wild. Their known extreme aggression in captivity suggests the species is markedly more territorial than most other turtles and tortoises. They seem to display a degree of social structure during the cooler dry season around the hydrothermal vents that line some river systems they inhabit.
The species is omnivorous, eating a wide variety of plant and animal matter, including the fruit and leaves of figs, as well as crustaceans, molluscs and insects. The turtle is native to freshwater streams, lagoons and rivers of the Northern Territory of Australia, as well as to the island of New Guinea, where it is believed to occur in all the larger, and some smaller, southward-flowing rivers.
The species experienced a population decline of more than 50% in the thirty years between 1981 and 2011. Although the turtles are protected in Indonesia under Law No. 5/1990 on Natural Resources and Ecosystems Conservation, smuggling occurs. Some 11,000 turtles captured from smugglers were released into their habitats in the Wania River, Papua Province, Indonesia, on 30 December 2010. 687 pig-nosed turtles were seized at an Indonesian airport in March 2013. They were reportedly destined for Hong Kong.