Eastern brown snake
Encyclopedia
The eastern brown snake (Pseudonaja textilis), often referred to as the common brown snake, is a species
of genus
Pseudonaja
. This snake is considered the second most venomous land snake based on its value (SC) in mice
. It is native to Australia
, New Guinea
and Indonesia
.
This species has an average length of 1.5–1.8 m and it is rarely larger than 2 m. Large eastern brown snakes are often confused with "king brown" snakes (Pseudechis australis), whose habitat they share in many areas.
s, a divided anal scale
and 45–75 divided subcaudal scales
.
, from the tip of Cape York
, along the coast
s and inland ranges of Queensland
, New South Wales
, Victoria
and South Australia
. They are also found in arid areas of the Northern Territory
, the far east of the Kimberley in Western Australia
and discontinuously in parts of New Guinea
, specifically northern Milne Bay Province
and Central Province
in Papua New Guinea
, and the Merauke region of Papua Province, in the Indonesia
n part of New Guinea. Because their mainly rodent
diet, they can often be found near houses and farms.
The snake occupies a varied range of habitats from wet to dry sclerophyll
forests (Eucalypt forests) and heath
s of coastal ranges, through to savannah
woodlands, inner grassland
s and arid scrublands. It is not found in rainforest
s or other wet areas.
(meaning it is active during the day). It is notorious for its speed and aggression throughout its habitats. When highly agitated, they hold their necks high, appearing in an upright S-shape. The snake usually seeks to flee when confronted, though it can be highly aggressive if provoked. This species is attracted to rural and farming areas, probably due to the large numbers of associated rodents. Such areas also normally provide shelter in the form of rubbish and other cover.
s, lizard
s, birds, rodent
s or other snakes.
neurotoxin
s) and blood coagulants. These snakes kept at venom supply laboratories yield an average of 2—10 mg
of venom per milking. As with most venomous snakes, the volume of venom produced is largely dependent on the size of the snake. Worrell (1963) reported a milking of 41.4 mg from a relatively large (2.1 m) specimen. This record is atypical, as on average the eastern brown snake yields a low volume of venom which is reported as not more than 10 mg.
Clinically, the venom of the eastern brown snake is known to cause diarrhea
, dizziness
, collapse or convulsions, renal failure
, paralysis
and cardiac arrest
.
Without medical treatment, bites can be fatal. As this species tends to initiate their defence with non-fatal bites, the untreated mortality rate in most snakebite
cases reported is 10—20% which is not very high.
conduction altered.
Sutherland (1983), reported,"that textilotoxin had direct presynaptic actions and no appreciable effect on muscle or acetylcholine receptors. The presynaptic blockade was due to the phosphoilpase, a component of the textilotoxin acting on the axolemma.
Hamilton et al. (1980), showed that the crude venom produced "coated omega figures" in the axolemma of the rat nerve terminals. Those figures are probably due to the action of the textilotoxin.
Barnett et al. (1980), isolated a postsynaptic neurotoxin called pseudonajatoxin A. It has 117 amino acid
residues and a molecular weight of 12,280. It causes irreversible blockade by firm binding to the acetylcholine receptors.
, wartrin plasma, factor V and factor X deficient plasmas and will hydrolyse peptide
p-nitroanilide substrale S-222.Ca++ and phospholipids have little effect on it. It was shown by Doery and Pearson (1961), that P. textilis venom was low in direct haemolytic properties and phospholipase. A.Kaire (1964), reported it had the least amount of heat stable anticoagulant than in most other Australian snakes.
A 16-year-old boy from Sydney died on 13 January 2007 after being bitten on the hand in a reserve at Whalan
.
9-year-old girl Milena Swilks from Rocky River
, south of Armidale
in rural New South Wales, died on 8 March 2007 after being bitten on the foot while picking corn. She collapsed and was taken to hospital unconscious, with the cause not known until after her death two hours later.
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 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...
Pseudonaja
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...
. This snake is considered the second most venomous land snake based on its value (SC) in mice
MICE
-Fiction:*Mice , alien species in The Hitchhiker's Guide to the Galaxy*The Mice -Acronyms:* "Meetings, Incentives, Conferencing, Exhibitions", facilities terminology for events...
. It is native to 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...
, New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
and Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
.
Description
Adult eastern brown snakes are highly variable in colour. Whilst usually a uniform shade of brown, they can have various patterns including speckles and bands, and range from a very pale fawn colour through to black, including orange, silver, yellow and grey. Juveniles can be banded and have a black head, with a lighter band behind, a black nape, and numerous red-brown spots on the belly.This species has an average length of 1.5–1.8 m and it is rarely larger than 2 m. Large eastern brown snakes are often confused with "king brown" snakes (Pseudechis australis), whose habitat they share in many areas.
Scalation
They have 17 rows of mid-body scaleSnake scales
Snakes, like other reptiles, have a skin covered in scales. Snakes are entirely covered with scales or scutes of various shapes and sizes. Scales protect the body of the snake, aid it in locomotion, allow moisture to be retained within, alter the surface characteristics such as roughness to aid in...
s, a divided anal scale
Anal scale
In snakes, the anal scale is the scale just in front of and covering the cloacal opening. This scale can be either single or paired . When paired, the division is oblique. It is preceded by the ventral scales and followed by the subcaudal scales....
and 45–75 divided subcaudal scales
Subcaudal scales
In snakes, the subcaudal scales are the enlarged plates on the underside of the tail. These scales may be either single or divided and are preceded by the anal scale....
.
Distribution and habitat
The eastern brown snake is found all the way along the East coast of AustraliaAustralia
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...
, from the tip of Cape York
Cape York Peninsula
Cape York Peninsula is a large remote peninsula located in Far North Queensland at the tip of the state of Queensland, Australia, the largest unspoilt wilderness in northern Australia and one of the last remaining wilderness areas on Earth...
, along the coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...
s and inland ranges of 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...
, 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...
, 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....
and 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...
. They are also found in arid areas of the Northern Territory
Northern Territory
The Northern Territory is a federal territory of Australia, occupying much of the centre of the mainland continent, as well as the central northern regions...
, the far east of the Kimberley in 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...
and discontinuously in parts of New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
, specifically northern Milne Bay Province
Milne Bay Province
Milne Bay is a province of Papua New Guinea. Its capital is Alotau. The province covers 14,000 km² of land and 252,990 km² of sea, within the province there are more than 600 islands, about 160 of which are inhabited...
and Central Province
Central Province (Papua New Guinea)
Central Province is a province in Papua New Guinea located on the southern coast of the country. It has a population of 183,983 people and is in size. The seat of government of Central Province, which is located within the National Capital District outside the province, is the Port Moresby suburb...
in Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
, and the Merauke region of Papua Province, in the Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
n part of New Guinea. Because their mainly rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
diet, they can often be found near houses and farms.
The snake occupies a varied range of habitats from wet to dry sclerophyll
Sclerophyll
Sclerophyll is the term for a type of vegetation that has hard leaves and short internodes . The word comes from the Greek sclero and phyllon ....
forests (Eucalypt forests) and heath
Heath (habitat)
A heath or heathland is a dwarf-shrub habitat found on mainly low quality acidic soils, characterised by open, low growing woody vegetation, often dominated by plants of the Ericaceae. There are some clear differences between heath and moorland...
s of coastal ranges, through to savannah
Savannah
Savannah or savanna is a type of grassland.It can also mean:-People:* Savannah King, a Canadian freestyle swimmer* Savannah Outen, a singer who gained popularity on You Tube...
woodlands, inner grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s and arid scrublands. It is not found in rainforest
Rainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s or other wet areas.
Behaviour
The eastern brown snake is diurnalDiurnal
Diurnal may refer to:* Diurnal cycle, any pattern that recurs daily** Diurnality, the behavior of animals and plants that are active in the daytime* Diurnal motion, the apparent motion of stars around the Earth...
(meaning it is active during the day). It is notorious for its speed and aggression throughout its habitats. When highly agitated, they hold their necks high, appearing in an upright S-shape. The snake usually seeks to flee when confronted, though it can be highly aggressive if provoked. This species is attracted to rural and farming areas, probably due to the large numbers of associated rodents. Such areas also normally provide shelter in the form of rubbish and other cover.
Diet
Being an opportunistic feeder, the eastern brown snake will consume almost any vertebrate animal, including frogFrog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s, lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
s, birds, rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....
s or other snakes.
Venom
The eastern brown snake is considered to be the second most venomous terrestrial snake. The venom with the values of 0.0365 mg/kg—0.053 mg/kg SC consists mostly of neurotoxins (pre-&post-synapticSynaptic
Synaptic may refer to:*Synapse, part of the nervous system*Synapsis, the pairing of two homologous chromosomes*Synaptic , a Linux graphical package management program for APT See also...
neurotoxin
Neurotoxin
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...
s) and blood coagulants. These snakes kept at venom supply laboratories yield an average of 2—10 mg
Mg
MG, M.G., M-G and variants may refer to:Business* MG Cars , a British automobile manufacturer, now part of SAIC* Champion Air , an American charter airline with IATA code MGEducation...
of venom per milking. As with most venomous snakes, the volume of venom produced is largely dependent on the size of the snake. Worrell (1963) reported a milking of 41.4 mg from a relatively large (2.1 m) specimen. This record is atypical, as on average the eastern brown snake yields a low volume of venom which is reported as not more than 10 mg.
Clinically, the venom of the eastern brown snake is known to cause diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, dizziness
Dizziness
Dizziness refers to an impairment in spatial perception and stability. The term is somewhat imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or a non-specific feeling such as giddiness or foolishness....
, collapse or convulsions, renal failure
Renal failure
Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
, paralysis
Paralysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
and cardiac arrest
Cardiac arrest
Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
.
Without medical treatment, bites can be fatal. As this species tends to initiate their defence with non-fatal bites, the untreated mortality rate in most snakebite
Snakebite
A snakebite is an injury caused by a bite from a snake, often resulting in puncture wounds inflicted by the animal's fangs and sometimes resulting in envenomation. Although the majority of snake species are non-venomous and typically kill their prey with constriction rather than venom, venomous...
cases reported is 10—20% which is not very high.
Neurotoxins
The neurotoxin of the eastern brown snake is textilotoxin (a presynaptic neurotoxin). It is a potent neurotoxin and represent 3% of the crude venom by weight. Southcott and Coulter (1979), reported that textilotoxin acted on the prejunctional terminal by selectively blocking the release of acetycholine after the appearance of the action potential. This blockage had no effect on the resting membrane potential of the muscle cells, nor was the nerveNerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
conduction altered.
Sutherland (1983), reported,"that textilotoxin had direct presynaptic actions and no appreciable effect on muscle or acetylcholine receptors. The presynaptic blockade was due to the phosphoilpase, a component of the textilotoxin acting on the axolemma.
Hamilton et al. (1980), showed that the crude venom produced "coated omega figures" in the axolemma of the rat nerve terminals. Those figures are probably due to the action of the textilotoxin.
Barnett et al. (1980), isolated a postsynaptic neurotoxin called pseudonajatoxin A. It has 117 amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
residues and a molecular weight of 12,280. It causes irreversible blockade by firm binding to the acetylcholine receptors.
Coagulants
Kellaway (1933), stated that P. textilis venom possessed a strong, highly diffusible coagulation factor. Denson (1969), concluded that the coagulation factor was a complete prothrombin activator. Masci et al. (1988) found the prothrombin activator to be a major component of the venom with a high molecular weight of larger than 200,000. They found it was related antigenically to the prothrombin activator of O. scutellatus venom, able to activate citrated blood plasmaBlood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
, wartrin plasma, factor V and factor X deficient plasmas and will hydrolyse peptide
Peptide
Peptides are short polymers of amino acid monomers linked by peptide bonds. They are distinguished from proteins on the basis of size, typically containing less than 50 monomer units. The shortest peptides are dipeptides, consisting of two amino acids joined by a single peptide bond...
p-nitroanilide substrale S-222.Ca++ and phospholipids have little effect on it. It was shown by Doery and Pearson (1961), that P. textilis venom was low in direct haemolytic properties and phospholipase. A.Kaire (1964), reported it had the least amount of heat stable anticoagulant than in most other Australian snakes.
Some snake bite cases
It is reported that at 8:45 am on February 4, 1981, an experienced herpetologist was cleaning the cage of a female eastern brown snake which had laid a clutch of 33 eggs on December 8, 1980. The snake suddenly bit the herpetologist's right thumb in a single fast strike. Two fangs marks were clearly visible 30 minutes later. The right arm was ensheathed in a self-applied compression bandage consisting of two rubber Esmarch's bandages, and the victim was transported to the hospital by ambulance. One hour after the release of the compression bandage, one ampule (50 ml) of CSL brown snake anti-venom mixed with 50 ml of dextrose saline was adminsitered intravenously. The herpetologist recovered and returned to work within six days.A 16-year-old boy from Sydney died on 13 January 2007 after being bitten on the hand in a reserve at Whalan
Whalan, New South Wales
Whalan is a suburb of Sydney, in the state of New South Wales, Australia. Whalan is located 44 kilometres west of the Sydney central business district, in the local government area of the City of Blacktown and is part of the Greater Western Sydney region....
.
9-year-old girl Milena Swilks from Rocky River
Rocky River (New South Wales)
Rocky River is a locality in northern New South Wales, Australia near the town of Uralla on the Northern Tablelands plateau.About two kilometres west of Uralla, was the gold mining area and associated village also called Rocky River. In 1851 W.F. Buchanan and J. Lucas reported to the Maitland...
, south of Armidale
Armidale, New South Wales
Armidale is a city in the Northern Tablelands, New South Wales, Australia. Armidale Dumaresq Shire had a population of 19,485 people according to the 2006 census. It is the administrative centre for the Northern Tablelands region...
in rural New South Wales, died on 8 March 2007 after being bitten on the foot while picking corn. She collapsed and was taken to hospital unconscious, with the cause not known until after her death two hours later.