Inland Taipan

## Description

The Inland taipan (Oxyuranus microlepidotus) is an extremely venomous snake endemic to semi-arid regions of central east Australia. Aboriginal Australians living in those regions named the snake dandarabilla. It was first described by Frederick McCoy in 1879 and then by William John Macleay in 1882, but for the next 90 years it was a mystery to the scientific community; no further specimens were found, and virtually nothing was added to the knowledge of this species until its rediscovery in 1972. Based on the median lethal dose value in mice, the venom of the inland taipan is by far the most toxic of any snake - much more so than even that of sea snakes - and it has the most toxic venom of any reptile when tested on human heart cell culture. The word "fierce" from its alternative name describes its venom, not its temperament.

## Appearance

The Inland taipan is dark tan in color, ranging from a rich, dark hue to brownish light green, depending on the season. Its back, sides, and tail may be different shades of brown and grey, with many scales having a wide blackish edge. These dark-marked scales occur in diagonal rows so that the marks align to form broken chevrons of variable length that are inclined backward and downward. The lowermost lateral scales often have an anterior yellow edge. The dorsal scales are smooth and without keels. The round-snouted head and neck are usually noticeably darker than the body (glossy black in winter, dark brown in summer), the darker color allowing the snake to heat itself while exposing only a smaller portion of the body at the burrow entrance. The eye is of average size with a blackish-brown iris and without a noticeable colored rim around the pupil.

## Distribution

Inland taipans occur in the semi-arid regions where Queensland and South Australia borders converge. In Queensland, they have been observed in the Channel Country region (e.g., Diamantina National Park, Durrie Station, Morney Plains Station, and Astrebla Downs National Park), and in South Australia, these snakes have been observed in the Marree-Innamincka NRM District (e.g., Goyder Lagoon Tirari Desert, Sturt Stony Desert, Coongie Lakes, Innamincka Regional Reserve, and Oodnadatta). An isolated population also occurs near Coober Pedy, South Australia. Inland taipans inhabit the black soil plains or floodplains, and gibber plains.

## Behavior

Inland taipans are solitary and diurnal creatures. They are most active in the early morning, spending their time basking in the sun and foraging. The rest part of the day they spend in shelters. On cooler days they may also be seen in the afternoon. Inland taipans adapt to their environment by changing the color of their skin during seasonal changes. They tend to become lighter during summer and darker during the winter. This seasonal color change serves the purpose of thermoregulation, allowing the snake to absorb more light in the colder months. Although extremely venomous and capable strikers, Inland taipans are usually quite shy and reclusive snakes and prefer to escape from trouble. However, they will defend themselves and strike if provoked, mishandled, or prevented from escaping. Because they live in such remote locations, Inland taipans seldom come in contact with people.

## Venom

The Inland taipan is an extremely fast and agile snake that can strike instantly with extreme accuracy, often striking multiple times in the same attack, and it envenomates in almost every case. The average quantity of venom delivered by this species is 44 mg and the maximum dose recorded is 110 mg. One bite's worth of venom is enough to kill 100 fully-grown men. The first local and general symptoms of a bite are local pain and variable non-specific effects which may include headache, nausea, vomiting, abdominal pain, diarrhea, dizziness, collapse, or convulsions leading to major organ effects: neurotoxicity, coagulopathy, rhabdomyolysis or kidney failure/damage and finally death. Because the Inland taipan can act so fast, it can kill a person within about 45 minutes. There have been reports of people experiencing the effects of the venom within half an hour.

## Diet

Inland taipans are carnivores. They consume only mammals, mostly rodents, such as the long-haired rat, the plains rat, and the introduced house mouse.

## Reproduction

The reproduction rate of Inland taipans depends in part on their diet: if there is not enough food, then these snakes will reproduce less. Females lay between 12-24 eggs in abandoned animal burrows and deep crevices. The eggs hatch two months later. In captivity, males reach reproductive maturity at 16 months of age and females become reproductively mature when they are 28 months old.

## Population

### Population threats

The main threats to Inland taipans include habitat loss and degradation. These snakes also suffer from the loss of their main food source, rodents. This happens mainly because of predation by non-native predators including cats and foxes.

### Population number

The IUCN Red List and other sources don’t provide the number of the Inland taipan total population size. Currently, this species is classified as Least Concern (LC) on the IUCN Red List.