Notechis
Encyclopedia
Tiger snakes are a type of venomous
serpent
found in southern regions of Australia
, including its coastal islands and Tasmania
. These snakes are highly variable in their colour, often banded like those on a tiger
, and forms in their regional occurrences. All populations are in the genus
Notechis, and their diverse characters have been described in further subdivisions of this group; they are sometimes described as distinct species and/or subspecies.
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 color. Individuals also show seasonal variation in color.
The total length can be up to 2.1 meters (7 ft). The patterning is darker bands, strongly contrasting or indistinct, which are pale to very dark in color. Coloration is composed of olive, yellow, orange-brown, or jet-black, the underside of the snake is lighter and yellow or orange. The tiger snake uses venom to dispatch their prey, and may bite an aggressor; they are potentially fatal to humans. Tolerant of low temperatures, the snake may be active on warmer nights.
When threatened they will flatten their body and raise their head above the ground in a classic pre-strike stance.
s) 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. Body capable of being flattened along entire length when snake is agitated or basking. Average length 0.9 m, maximum length 1.2 m but has been recorded at 2.0 m (or ~6.6 ft). Highly variable in colour, with base colours of brown, grey olive, green with lighter crossbands usually of creamy yellow. Occasionally unbanded specimens are found. Scales appear like overlapping shields, especially around the neck. Ventrals 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 has a head that is distinct from its robust body, and grows to 2.0 m in length. Dorsally, steel-blue to black 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
, averaging 1.9 m (over 6 feet) in length. Dorsally, 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.
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 1.5 m in length. Dorsally, 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 range they inhabit.
The Peninsula tiger snake has a blunt head distinct from a robust body. Averages 1.1 m in length. Roxby Island specimens are much smaller, averaging 0.86 m in length. Dorsally, 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. Mid-body 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.
Tiger snakes are found in coastal environments, wetlands, and creeks where they often form territories. Areas with an abundance of prey can support large populations. The species' distribution extends from the south of Western Australia
through to South Australia
, Tasmania
, up through Victoria, and New South Wales
. Its common habitat includes the coastal areas of Australia.
snakes. There are two widely recognized species
of this genus, Notechis scutatus (Peters, 1861) and Notechis ater (Krefft, 1866), which show further variety in their characteristics. Several authors have published revisions or described subspecies
of these species. Others consider the names contained by this taxonomic arrangement to be unwarranted, and describe Notechis as a monotypic
genus. Various authorities accept some or all the systematics previously applied but most agree that a revision of the genus is needed. Names for these subdivisions include the Western types, appended to both species names as occidentalis (Glauert 1948) The island groups have also been described as subspecies: Chappell Island tiger snake as N. ater serventyi (Warrell, 1963), King Island and Tasmanian tiger snakes subspecies N. ater humphreysi, (Warrell, 1963) and the Peninsula tiger snake N. ater niger( Kinghorn 1921).
* Not including the nominate subspecies (typical form).
, coagulant
s, haemolysins and myotoxin
s. Symptoms of a bite include localized pain in the foot and neck region, tingling, numbness, and sweating, followed by a fairly rapid onset of breathing difficulties and paralysis. In a study, the untreated mortality rate from its bites is reported to be between 40-60%.
Treatment is the same for all Australian venomous snake
s. The Pressure Immobilization Method (PIM) is used to inhibit the flow of venom through the lymphatic system. Broad thick bandages are applied over the bite, then down and back along the limb to the armpit or groin. The affected limb is then immobilized with a splint. Identification of the venom is possible if traces are left near the wound. Identifying the snake is not necessary if bitten in Tasmania, however, as the same antivenom is used to treat all Tasmanian snakes' bites. The availability of antivenom has greatly reduced the incidence of fatal tiger snake bites. The number of deaths is now exceeded by the brown snake
.
. It is also illegal to export a native Australian snake.
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...
serpent
Serpent
Serpent may refer to:* Serpent, a synonym for snake* Serpent , the name given to a snake in a religious or mythological context* Serpent , said to have tempted Adam and Eve in the Garden of Eden* Serpent in astronomy...
found in southern regions of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, including its coastal islands and Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
. These snakes are highly variable in their colour, often banded like those on a tiger
Tiger
The tiger is the largest cat species, reaching a total body length of up to and weighing up to . Their most recognizable feature is a pattern of dark vertical stripes on reddish-orange fur with lighter underparts...
, and forms in their regional occurrences. All populations are in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Notechis, and their diverse characters have been described in further subdivisions of this group; they are sometimes described as distinct species and/or subspecies.
Description
A genus of large venomous snakeSnake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
in the family Elapidae
Elapidae
Elapidae is a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America and South America and aquatically in the Pacific and Indian Oceans...
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 color. Individuals also show seasonal variation in color.
The total length can be up to 2.1 meters (7 ft). The patterning is darker bands, strongly contrasting or indistinct, which are pale to very dark in color. Coloration is composed of olive, yellow, orange-brown, or jet-black, the underside of the snake is lighter and yellow or orange. The tiger snake uses venom to dispatch their prey, and may bite an aggressor; they are potentially fatal to humans. Tolerant of low temperatures, the snake may be active on warmer nights.
When threatened they will flatten their body and raise their head above the ground in a classic pre-strike stance.
Reproduction
Tiger snakes give birth to 12 to 40 live young, an exceptional record was made of 64 from an eastern female.Morphs
The widely dispersed populations (sometimes referred as polymorphPolymorphism (biology)
Polymorphism in biology occurs when two or more clearly different phenotypes exist in the same population of a species — in other words, the occurrence of more than one form or morph...
s) 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. Body capable of being flattened along entire length when snake is agitated or basking. Average length 0.9 m, maximum length 1.2 m but has been recorded at 2.0 m (or ~6.6 ft). Highly variable in colour, with base colours of brown, grey olive, green with lighter crossbands usually of creamy yellow. Occasionally unbanded specimens are found. Scales appear like overlapping shields, especially around the neck. Ventrals 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 has a head that is distinct from its robust body, and grows to 2.0 m in length. Dorsally, steel-blue to black 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
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, averaging 1.9 m (over 6 feet) in length. Dorsally, 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.
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 1.5 m in length. Dorsally, 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 range they inhabit.
The Peninsula tiger snake has a blunt head distinct from a robust body. Averages 1.1 m in length. Roxby Island specimens are much smaller, averaging 0.86 m in length. Dorsally, 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. Mid-body 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.
Habitat
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
through to South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...
, Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
, up through Victoria, and New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
. Its common habitat includes the coastal areas of Australia.
Taxonomy
The genus Notechis is placed in the family of elapidElapidae
Elapidae is a family of venomous snakes found in tropical and subtropical regions around the world, terrestrially in Asia, Australia, Africa, North America and South America and aquatically in the Pacific and Indian Oceans...
snakes. There are two widely recognized species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of this genus, Notechis scutatus (Peters, 1861) and Notechis ater (Krefft, 1866), which show further variety in their characteristics. Several authors have published revisions or described subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of these species. Others consider the names contained by this taxonomic arrangement to be unwarranted, and describe Notechis as a monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
genus. Various authorities accept some or all the systematics previously applied but most agree that a revision of the genus is needed. Names for these subdivisions include the Western types, appended to both species names as occidentalis (Glauert 1948) The island groups have also been described as subspecies: Chappell Island tiger snake as N. ater serventyi (Warrell, 1963), King Island and Tasmanian tiger snakes subspecies N. ater humphreysi, (Warrell, 1963) and the Peninsula tiger snake N. ater niger( Kinghorn 1921).
Species
| Species | Authority | Subsp.* | Common name | Geographic range |
|---|---|---|---|---|
| N. ater | Krefft, 1866 | 3 | Black tiger snake | Australia Australia Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area... (Western Australia Western Australia Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east... , South Australia South Australia South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland... , Tasmania Tasmania Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart... ) |
| N. scutatus | Peters, 1861 | 1 | Mainland tiger snake | Australia (New South Wales New South Wales New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales... , Queensland Queensland Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean... , South Australia, Victoria Victoria (Australia) Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively.... , Western Australia) |
* Not including the nominate subspecies (typical form).
Venom
Tiger snakes possess a potent neurotoxinNeurotoxin
A neurotoxin is a toxin that acts specifically on nerve cells , usually by interacting with membrane proteins such as ion channels. Some sources are more general, and define the effect of neurotoxins as occurring at nerve tissue...
, coagulant
Coagulant
Coagulant can refer to:* flocculation* coagulation agent...
s, haemolysins and myotoxin
Myotoxin
Myotoxins are small, basic peptides found in snake venoms, such as in that of certain rattlesnakes. This involves a non-enzymatic mechanism that leads to severe muscle necrosis...
s. Symptoms of a bite include localized pain in the foot and neck region, tingling, numbness, and sweating, followed by a fairly rapid onset of breathing difficulties and paralysis. In a study, the untreated mortality rate from its bites is reported to be between 40-60%.
Treatment is the same for all Australian venomous snake
Venomous snake
"Poisonous snake" redirects here. For true poisonous snakes, see Rhabdophis.Venomous snakes are snakes which have venom glands and specialized teeth for the injection of venom...
s. The Pressure Immobilization Method (PIM) is used to inhibit the flow of venom through the lymphatic system. Broad thick bandages are applied over the bite, then down and back along the limb to the armpit or groin. The affected limb is then immobilized with a splint. Identification of the venom is possible if traces are left near the wound. Identifying the snake is not necessary if bitten in Tasmania, however, as the same antivenom is used to treat all Tasmanian snakes' bites. The availability of antivenom has greatly reduced the incidence of fatal tiger snake bites. The number of deaths is now exceeded by the brown snake
Pseudonaja
Pseudonaja is a genus of venomous elapid snakes native to Australia. Members are known commonly as brown snakes and are considered to be one of the most dangerous snakes in the country; even young snakes are capable of delivering a fatal envenomation to a human.- Species :* Dugite or Spotted...
.
Conservation
In most Australian states they are protected species, and to kill or injure one incurs a fine of up to $7,500 as well as a jail sentence of 18 months in some states. It is also illegal to export a native Australian snake.
External links
- video of Mainland Tiger snakes
- Information on bites from survivaliq.com
- Information on the genus from snakeshow.net
- Integrated Taxonomic Information System - Notechis