[6] The genus name Crocodylus comes from the Greek kroko which means a pebble and deilos, a worm or man, referring to the knobbly appearance of the dorsal surface of the reptile.

[6] Phylogenetic evidence supports Crocodylus diverging from its closest recent relative, the extinct Voay of Madagascar, around 25 million years ago, near the Oligocene/Miocene boundary.

[10] Below is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data,[11] as revised by the 2021 Hekkala et al. paleogenomics study using DNA extracted from the extinct Voay.

[10] Note: Crocodylus halli is missing in this diagram, as it was declared a separate species a year after Lee & Yates published their findings.

The colouring is similar to that of the freshwater crocodile (Crocodylus johnsoni) of northern Australia, but the snout is somewhat shorter and broader.

[4] It has been known to enter brackish waters but is very rare in coastal areas, and never found in the presence of the competing saltwater crocodile (C.

A floating nest composed of vegetation is made in a shallow water location such as in an overgrown channel, at the edge of a lake, on a scroll swale or beside a stream.

[4][16] Newly hatched New Guinea crocodiles feed on aquatic insects, spiders, tadpoles, freshwater snails, frogs, fish and small mammals.

An adult's diet is largely fish, caught by sweeping the snout sideways and snapping at the prey, but also includes shrimps, crabs, frogs, snakes, birds and medium-sized mammals.

A crocodile catches its prey by stealth with a flick of its head, impaling it with its sharp teeth and gripping and crushing it.

This crocodile is surprisingly agile and can lunge its body upward into the air to catch bats, flying birds, and leaping fish.

[16] The distress noises of a youngster when handled at a ranching facility was observed to cause all the larger animals to become involved in frenzied activity, with some rushing towards the juvenile and others thrashing about in the water and slapping their heads down on the surface.

It is included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

[2] The skin of the New Guinea crocodile is valuable and in the 1950s and 1960s the animals in the northern population were heavily hunted to a point where they might have become extinct.

[15] Some eggs and hatchlings are still removed from the nest and raised in enclosures and a similar programme has more recently been initiated for southern populations.

[4] In July 2018, a man was reportedly killed by a saltwater crocodile in a breeding farm in West Papua, Indonesia.