Adults average about 2m in length, but may reach as much as 3m. Robustly built, it has a long head that is slightly distinct from the neck. The anterior supralabials have thermosensitive pits.

Scalation includes a pair of undivided parietal scales and a single loreal scale on either side of the head. On the body, the dorsal scales number 45-55 at midbody, the ventral scales 270-300, the anal scale is single and there are 60-90 paired subcaudal scales.

The color pattern consists of a uniform, iridescent dark blackish brown dorsal color. The belly is a dull to bright yellow that includes the first few rows of dorsal scales. The throat is cream colored, while the upper labials are light gray-brown with dark brown or black spots.

Found in Australia in the Kimberley district of northern Western Australia from around Broome east through Northern Territory at least as far south as Mataranka to the coast of central Queensland to near MacKay. Also found in the Sir Charles Hardy Islands, on Cornwallis Island in the Torres Strait, and in Papua New Guinea, Western District, in the lower Fly River region at least as far inland as Lake Daviumbo. The type locality given is "Port Bowen" (Port Clinton, Queensland, Australia).

The highest population density is reached on the Adelaide River floodplains in the Northern Territory.

An opportunistic feeder, its diet consists of a variety of vertebrates. However, a study by Madsen and Shine (1996) revealed that on the Adelaide River floodplains this species preys mainly on dusky rats (Rattus colletti).

Mating takes place in July-August, which is the middle of the dry season. This is followed by a gestation period of about a month, after which females lay an average of 12 eggs. The hatchlings emerge after 57-61 days of incubation and are each about 30cm in length.

Popular and hardy captive, though young ones may be quite snappy.