Eastern brown snake
The eastern brown snake, often referred to as the common brown snake, is a species of extremely venomous snake in the family Elapidae. The species is native to eastern and central Australia and southern New Guinea. It was first described by André Marie Constant Duméril, Gabriel Bibron, and Auguste Duméril in 1854. The adult eastern brown snake has a slender build and can grow to in length. The colour of its surface ranges from pale brown to black, while its underside is pale cream-yellow, often with orange or grey splotches. The eastern brown snake is found in most habitats except dense forests, often in farmland and on the outskirts of urban areas, as such places are populated by its main prey, the house mouse. The species is oviparous. The International Union for Conservation of Nature classifies the snake as a least-concern species, though its status in New Guinea is unclear.
It is considered the world's second-most venomous land snake after the inland taipan, based on its value in mice. The main effects of its venom are on the circulatory system—coagulopathy, haemorrhage, cardiovascular collapse, and cardiac arrest. One of the main components of the venom is the prothrombinase complex pseutarin-C, which breaks down prothrombin.
Taxonomy
, the surgeon-general of the First Fleet to New South Wales, wrote, A Journal of a Voyage to New South Wales in 1790, which described many Australian animal species for the first time. In it, he reported a snake that fits the description of the eastern brown snake, but did not name it. French zoologists André Marie Constant Duméril, Gabriel Bibron, and Auguste Duméril were the first to describe the species in 1854. They gave it the binomial name Furina textilis – furine tricotée in French – from a specimen collected in October 1846 by Jules Verreaux, remarking that the fine-meshed pattern on the snake's body reminded him of fine stockings, which was the inspiration for the name. Due to differences in appearance, different specimens of the eastern brown snake were categorised as different species in the early 19th century. German herpetologist Johann Gustav Fischer described it as Pseudoelaps superciliosus in 1856, from a specimen collected from Sydney. German-British zoologist Albert Günther described the species as Demansia annulata in 1858. Italian naturalist Giorgio Jan named Pseudoelaps sordellii and Pseudoelaps kubingii in 1859.Gerard Krefft, curator of the Australian Museum, reclassified Duméril, Bibron, and Duméril's species in the genus Pseudonaia in 1862 after collecting multiple specimens and establishing that the markings of young snakes faded as they grew into adult brown snakes. He concluded the original description was based on an immature specimen and sent an adult to Günther, who catalogued it under the new name the same year when cataloguing new species of snakes in the British Museum's collection. After examining all specimens, Günther concluded that Furina textilis and Diemansia annulata were named for young specimens and Pseudoelaps superciliosus, P. sordelli, and P. kubingii were named for adults, and all represented the same species, which he called Diemenia superciliosa. Belgian-British naturalist George Albert Boulenger called it Diemenia textilis in 1896, acknowledging Duméril, Bibron, and Duméril's name as having priority. In subsequent literature, it was known as Demansia textilis as Diemenia was regarded as an alternate spelling of Demansia.
The brown snakes were moved from Diemenia/Demansia to Pseudonaja by Australian naturalist Eric Worrell in 1961 on the basis of skull morphology, and upheld by American herpetologist Samuel Booker McDowell in 1967 on the basis of the muscles of the venom glands. This classification has been followed by subsequent authors. In 2002, Australian herpetologist Richard W. Wells split the genus Pseudonaja, placing the eastern brown snake in the new genus Euprepiosoma, though this has not been recognised by other authors, and Wells has been strongly criticised for a lack of rigour in his research.
Within the genus Pseudonaja, the eastern brown snake has the largest diploid number of chromosomes at 38; those of the other species range from 30 to 36. A 2008 study of mitochondrial DNA across its range showed three broad lineages – a southeastern clade from South Australia, Victoria, and southeastern and coastal New South Wales; a northeastern clade from northern and western New South Wales and Queensland; and a central Australian clade from the Northern Territory. The central Australian clade had colonised the region around Merauke in southern West Papua, and the northeastern clade had colonised Milne Bay, Oro, and Central Provinces in eastern Papua New Guinea in the Pleistocene via landbridges between Australia and New Guinea.
P. textilis is monotypic. Raymond Hoser described all New Guinea populations as Ps. t. pughi based on a differing maxillary tooth count from Australian populations; this difference was inconsistent, and as no single New Guinea population is genetically distinct, the taxon is not recognised. Wells and C. Ross Wellington described Pseudonaja ohnoi in 1985 from a large specimen from Mount Gillen near Alice Springs, distinguishing it on the basis of scale numbers, but it is not regarded as distinct.
The species is commonly called the eastern brown snake or common brown snake. It was known as marragawan to the Eora and Darug inhabitants of the Sydney basin. To the Dharawal of the Illawarra, it is goobalaang. The Dharawal and Awabakal held ceremonies for the eastern brown snake. Warralang is the reconstructed name in the Wiradjuri language of southern New South Wales.
Description
The eastern brown snake is of slender to average build with no demarcation between its head and neck. Its snout appears rounded when viewed from above. Most specimens have a total length up to, with some large individuals reaching. The maximum recorded total length for the species is. Evidence indicates that snakes from the northern populations tend to be larger than those from southern populations. The adult eastern brown snake is variable in colour. Its upper parts range from pale to dark brown, or sometimes shades of orange or russet, with the pigment more richly coloured in the posterior part of the dorsal scales. Eastern brown snakes from Merauke have tan to olive upper parts, while those from eastern Papua New Guinea are very dark grey-brown to blackish.The eastern brown snake's fangs are small compared to those of other Australian venomous snakes, averaging in length or up to in larger specimens, and are apart. The tongue is dark. The iris is blackish with a paler yellow-brown or orange ring around the pupil. The snake's chin and under parts are cream or pale yellow, sometimes fading to brown or grey-brown towards the tail. Often, orange, brown, or dark grey blotches occur on the under parts, more prominent anteriorly. The ventral scales are often edged with dark brown on their posterior edges.
Juveniles can vary in markings, but generally have a black head, with a lighter brown snout and band behind, and a black nuchal band. Their bodies can be uniform brown, or have many black bands, or a reticulated pattern, with all darker markings fading with age. Snake clutches in colder areas tend have a higher proportion of young snakes with banded markings on their bodies.
Its yellowish under parts serve to distinguish it from the dugite and peninsula brown snake, which are entirely brown or brown with grey under parts. The eastern brown snake has flesh-pink skin inside its mouth, whereas the northern brown snake and western brown snake have black skin. Large eastern brown snakes are often confused with mulga snakes, whose habitat they share in many areas, but may be distinguished by their smaller heads. Juvenile eastern brown snakes have head markings similar to red-naped snakes, grey snakes , Dwyer's snakes , and the curl snake.
Scalation
The number and arrangement of scales on a snake's body are a key element of identification to species level. The eastern brown snake has 17 rows of dorsal scales at midbody, 192 to 231 ventral scales, 45 to 75 divided subcaudal scales, and a divided anal scale. Its mouth is bordered by six supralabial scales above, and seven sublabial scales below. Its nasal scale is almost always undivided, and rarely partly divided. Each eye is bordered posteriorly by two or rarely three postocular scales.Distribution and habitat
The eastern brown snake is found along the east coast of Australia, from Malanda in far north Queensland, along the coasts and inland ranges of Queensland, New South Wales, Victoria, and to the Yorke Peninsula in South Australia. Disjunct populations occur on the Barkly Tableland and the MacDonnell Ranges in the Northern Territory. and 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 South Papua, in the Indonesian part of New Guinea. It is common in southeastern Queensland between Ipswich and Beenleigh.The eastern brown snake occupies a varied range of habitats from dry sclerophyll forests and heaths of coastal ranges, through to savannah woodlands, inner grasslands, and arid scrublands and farmland, as well as drier areas that are intermittently flooded. It is more common in open habitat and also farmland and the outskirts of urban areas. It is not found in alpine regions, or on Phillip Island. Because of its mainly rodent diet, it can often be found near houses and farms. Such areas also provide shelter in the form of rubbish and other cover; the snake can use sheets of corrugated iron or buildings as hiding spots, as well as large rocks, burrows, and cracks in the ground.
In December 2023 an eastern brown snake interrupted play at the Brisbane International tennis tournament. Play was paused for 40 minutes, while the animal was removed by a professional snake catcher.