Inland taipan

The inland taipan (Oxyuranus microlepidotus)—also called the western taipan, small-scaled snake, or fierce snake—belongs to the Elapidae family and is native to the semiarid parts of central-eastern Australia. Aboriginal communities in areas where Karnic languages are spoken know it as dandarabilla. Frederick McCoy formally described the species in 1879, and William John Macleay did so again in 1882. For nearly 90 years after that, scientists knew almost nothing about it: no further specimens were collected, and its biology remained a blank until it was rediscovered in 1972.

Venom

Based on tests measuring the median lethal dose (LD50) of its venom in lab mice, the inland taipan is widely considered the world’s most venomous snake. Drop for drop, its venom is far more toxic than any sea snake tested. It also has the most toxic venom of any reptile when tested on human heart cell cultures. The snake specializes in hunting mammals, and its venom is tailored to killing warm-blooded prey.

A single bite is thought to carry enough venom to kill more than 100 adult humans. Despite this extreme potency, the inland taipan is usually shy and reclusive, with a generally calm temperament. It rarely encounters people because it lives in remote areas. In practice, the coastal taipan (Oxyuranus scutellatus) is often considered more dangerous, mainly because of how it behaves around humans and its presence near populated coastal regions.

Taxonomy

The “fierce” in one of its common names refers to the strength of its venom, not its disposition. Among Aboriginal people from the area now called Goyder Lagoon in northeastern South Australia, the inland taipan was traditionally called dandarabilla. The species was first described scientifically in 1879, when two specimens were collected where the Murray and Darling Rivers meet in northwestern Victoria. Frederick McCoy named them Diemenia microlepidota, the “small-scaled brown snake.” In 1882, a third specimen was found near Bourke, New South Wales, and William John Macleay described it as Diemenia ferox, thinking it was a different species.

No more material turned up until the 1970s. In 1896, George Albert Boulenger moved both taxa to the genus Pseudechis (black snakes), calling them Pseudechis microlepidotus and P. ferox. In 1956, working only from published descriptions and notes, James Roy Kinghorn considered ferox a synonym of microlepidotus and proposed the new genus Parademansia for the species.

In 1963, Eric Worrell thought Parademansia microlepidotus was the same species as Oxyuranus scutellatus (then simply called the “taipan”). However, in September 1972, an unclassified snake head collected by a grazier on a Channel Country station west of Windorah in southwestern Queensland was sent to the Queensland Museum. Herpetologists Jeanette Covacevich and Charles Tanner went to the site, found 13 live specimens, and thereby rediscovered the long-lost “western taipan” Parademansia microlepidotus. In 1976, Covacevich and Wombey argued that Parademansia microlepidotus was distinct enough to deserve its own genus, a view Harold Cogger shared.

Later, in 1981, Covacevich, McDowell, Tanner, and Mengden compared anatomical features, chromosomes, and behavior of the two then-recognized species Oxyuranus scutellatus and Parademansia microlepidota and concluded both belonged in a single genus. The older name Oxyuranus (created in 1923) therefore took priority and was adopted for the combined genus. Since the early 1980s, the inland taipan’s current binomial name has been Oxyuranus microlepidotus. The genus name Oxyuranus comes from the Greek oxys (“sharp” or “needle-like”) and ouranos (“arch,” specifically the arch of the palate), referring to the needle-like front process on the palatal arch.

Distribution and habitat

The species name microlepidotus is Latin for “small-scaled,” referring to the small body scales, and is the source of the common name “small-scaled snake.” Once Covacevich et al. (1981) showed that the fierce snake (formerly Parademansia microlepidota) belonged to the genus Oxyuranus, the name “taipan” (from the Aboriginal term dhayban) was kept for O. scutellatus, which became known as the coastal taipan (or “eastern taipan”), while O. microlepidotus came to be widely called the “inland (or western) taipan.” The inland taipan lives on cracking-clay plains in semiarid areas near the border of Queensland and South Australia. In Queensland, it has been recorded in the Channel Country bioregion, including Diamantina National Park, Durrie Station, Morney Plains Station, and Astrebla Downs National Park. In South Australia, it has been seen in the Marree–Innamincka NRM district, including Goyder Lagoon, the Tirari Desert, Sturt Stony Desert, Coongie Lakes, Innamincka Regional Reserve, and near Oodnadatta. An isolated population also exists near Coober Pedy, South Australia.

Conservation status

Two historical records exist from farther southeast: at the junction of the Murray and Darling Rivers in northwestern Victoria (1879) and near Bourke, New South Wales (1882), but the species has not been recorded in either state since the late 1800s. Like all native snakes in Australia, the inland taipan is protected by law. The species was assessed for the IUCN Red List for the first time in July 2017, and in 2018 it was listed as least concern. The assessment notes that the species is widespread within its range and is not thought to be in overall decline, although the potential impacts of threats require further investigation and may need more study.