Notechis is a genus of large venomous
snakes in the family
Elapidae restricted to subtropical and temperate regions of Australia. Tiger snakes are a large group of distinct populations, which may be isolated or overlapping, with extreme variance in size and colour. Individuals also show seasonal variation in colour. The total length is typically about The patterning is darker bands, strongly contrasting or indistinct, which are pale to very dark in colour. Colouration is olive, yellow, orange-brown, or jet-black, and the underside of the snake is light yellow or orange. Tiger snakes use venom to kill prey, and may also bite an aggressor; they are potentially fatal to humans. Tolerant of low temperatures, the snake may be active on warmer nights. When threatened, they flatten their bodies and raise their heads above the ground in a classic prestrike stance.
Morphs The widely dispersed populations (sometimes referred as
polymorphs) show some conformity in their descriptions, but these characters may be shared by separate or adjacent groups. Tiger snakes are also identified by the region or island in which the forms occur, which is prefixed to a common name. The
common tiger snake has a flat, blunt head, slightly distinct from a robust body. Its body is capable of being flattened along its entire length when the snake is agitated or basking. Its average length is , with a maximum length of , but has been recorded at . Highly variable in colour, its base colours are brown, grey olive, or green with lighter crossbands usually of creamy yellow. Occasionally, unbanded specimens are found. Scales appear like overlapping shields, especially around the neck. Ventral scales number 140 to 190, subcaudals 35 to 65, mid-body in 17 or 19 rows and the anal scale is single. The
western tiger snake head is distinct from its robust body, and grows to in length. Dorsally, it is steel-blue to black in color with bright yellow bands; unbanded specimens occur. The ventral surface is yellow, tending black towards the tail. Midbody scales are in 17 or 19 rows, ventrals number 140 to 165, subcaudals 36 to 51 (single) and the anal scale is single (rarely divided). The
Chappell Island tiger snake has a blunt head distinct from a robust body. The giant of the tiger snakes
species, it averages 1.9 m (over 6 ft) in length. Dorsally, its colour is olive-brown to almost black, sometimes with lighter crossbands. The ventral surface is usually lighter in colour. Juveniles are banded. Mid-body scales are in 17 rows; ventrals number 160 to 171, subcaudals 47 to 52 (single), and the anal scale is single. These snakes are quite docile. . In Tasmania. The
King Island and
Tasmanian tiger snakes each have a blunt head distinct from a robust body. Younger snakes may be slimmer and similar to other tiger snakes, eventually growing up to in length. Dorsally, they may be jet black, jet black with lighter crossbands, grey with black flecks forming faint bands, or an unbanded grey or brown. The ventral surface is usually a lighter colour. Midbody scales are in 19, 17 or sometimes 15 rows, ventrals number 161 to 174, subcaudals 48 to 52 (single) and the anal scale is single. Tasmanian tiger snakes tend to be quiet snakes, probably due to the lower temperature ranges they inhabit. The
Peninsula tiger snake has a blunt head distinct from a robust body; it averages in length. Roxby Island specimens are much smaller, averaging in length. Dorsally, it is generally jet black, sometimes with white or cream markings around the lips and chin. On Kangaroo Island, specimens are highly variable in colour, often exhibiting banding and uniform brown colours. The ventral surface is dark grey to black, with some specimens on Kangaroo Island even possessing red bellies. The ventral surface becomes much lighter prior to shedding. Juveniles nearly always have banding. Midbody scales are in 17, 18, 19 and rarely 21 rows, ventrals number 160 to 184, subcaudals 45 to 54 (single) and the anal scale is single. The subspecies
Notechis ater ater, found away from mainland Australia, is typically uniformly black. As with most snakes, the colours vary widely between individuals and are an unreliable means of identifying subspecies. Accurate identification is best performed with a venom test kit or scale count. ==Reproduction==