Red-bellied Black Snake

The red-bellied black snake has a glossy black top body with a light-grey snout and brown mouth, and a completely black tail. It lacks a well-defined neck; its head merges seamlessly into the body. Its flanks are bright red or orange, fading to pink or dull red on the belly. All these scales have black margins. Snakes from northern populations tend to have lighter, more cream or pink bellies. The red-bellied black snake is on average around 1.25 m (4 ft 1 in) in total length (tail included), the longest individual recorded at 2.55 m (8 ft 4 in). Males are generally slightly larger than females. A large 2 m (6 ft 7 in) specimen caught in Newcastle has been estimated to weigh around 10 kg (22 lb). The red-bellied black snake can have a strong smell, which some field experts have used to find the snakes in the wild. Like all elapid snakes, it is proteroglyphous (front-fanged). Juveniles are similar to the eastern small-eyed snake (Cryptophis nigrescens), with which they can be easily confused, although the latter species lacks the red flanks. Other similar species include the blue-bellied black snake (Pseudechis guttatus) and copperheads of the genus Austrelaps. An early misconception was that the red-bellied black snake was sexually dimorphic, and that the eastern brown snake (Pseudonaja textilis) was the female form. …

The red-bellied black snake is native to the east coast of Australia, where it is one of the most commonly encountered snakes. It can be found in the urban forest, woodland, plains, and bushland areas of the Blue Mountains, Canberra, Sydney, Brisbane, Melbourne, Cairns, and Adelaide. The Macquarie Marshes mark a western border to its distribution in New South Wales, and Gladstone in central Queensland marks the northern limit to the main population. To the south, it occurs across eastern and central Victoria, and extends along the Murray River into South Australia. Disjunct populations occur in the southern Mount Lofty Ranges in South Australia and in North Queensland. The red-bellied black snake is most commonly seen close to dams, streams, billabongs, and other bodies of water, although they can venture up to 100 m (350 ft) away, including into nearby backyards. In particular, it prefers areas of shallow water with tangles of water plants, logs, or debris.

The red-bellied black snake can hide in many places in its habitat, including logs, old mammal burrows, and grass tussocks. It can flee into water and hide there; one was reported as staying submerged for 23 minutes. When swimming, it may hold its full head or its nostrils above the water's surface. At times, it may float without moving on the water surface, thus looking like a stick. Within its habitat, the red-bellied black snake appears to have a home range or territory with which it is familiar and within which it generally remains. A 1987 field study in three New South Wales localities found that these areas vary widely, from 0.02 to 40 ha (0.05 to 100 acres) in size. Within its territory, it may have some preferred places to reside. The red-bellied black snake is generally not an aggressive species, typically withdrawing when approached. If provoked, it recoils into a striking stance as a threat, holding its head and front part of its body horizontally above the ground and widening and flattening its neck. It may bite as a last resort. It is generally active by day, though nighttime activity occasionally has been recorded. When not hunting or basking, it may be found beneath timber, rocks, and rubbish or down holes and burrows. The red-bellied black snake is active when its body temperature is between 28 and 31 °C (82 and 88 °F). …

The red-bellied black snake was first described and named by English naturalist George Shaw in Zoology of New Holland (1794) as Coluber porphyriacus. Incorrectly assuming it was harmless and not venomous, he wrote, "This beautiful snake, which appears to be unprovided with tubular teeth or fangs, and consequently not of a venomous nature, is three, sometimes four, feet in nature." The specific name, porphyriacus, is derived from the Greek porphyrous, which can mean "dark purple", "red-purple" or "beauteous". It was the first Australian elapid described. The syntype is presumed lost. French naturalist Bernard Germain de Lacépède described it under the name Trimeresurus leptocephalus in 1804. His countryman René Lesson described it as Acanthophis tortor in 1826. German biologist Hermann Schlegel felt it was allied with cobras and called it Naja porphyrica in 1837.

The genus Pseudechis was created for this species by German biologist Johann Georg Wagler in 1830; several more species have been added to the genus subsequently. The generic name, Pseudechis, is derived from the Greek words pseudēs "false", and echis "viper". Snake expert Eric Worrell, in 1961, analysed the skulls of the genus and found that of the red-bellied black snake to be the most divergent. …