Wombat

Wombats are sturdy, short-legged marsupials that belong to the family Vombatidae and are found only in Australia. They have a muscular build, four legs, and a small, stubby tail. Adult wombats typically measure about one meter in length and weigh between 20 and 35 kilograms. These animals are highly adaptable and live in a variety of habitats, including forests, mountains, and heathlands across southern and eastern Australia, as well as on the island of Tasmania. There is also a small, isolated population of around 300 hectares in Epping Forest National Park in central Queensland.

The word "wombat" comes from the Dharug language, spoken by the Aboriginal people who originally lived in the Sydney area. It was first recorded in January 1798 by John Price and James Wilson, two Europeans who had adopted Aboriginal ways, while visiting what is now Bargo, New South Wales. Price described the animal as about 20 inches high, with short legs, a thick body, a large head, round ears, and very small eyes, noting it was very fat and resembled a badger. Early settlers often called wombats badgers because of their size and habits, which led to place names like Badger Creek in Victoria and Badger Corner in Tasmania. Over time, the spelling of the name went through many variations, including "wambat," "whombat," "womat," "wombach," and "womback."

The evolutionary history of wombats is not well understood, even with genetic studies. They are thought to have split from other Australian marsupials relatively early, with estimates ranging from 25 to 40 million years ago. Some prehistoric wombat species were much larger than modern ones. The largest known, *Phascolonus*, went extinct about 40,000 years ago and may have weighed up to 360 kilograms.

Wombats are skilled diggers, using their rodent-like front teeth and strong claws to create extensive burrow systems. A unique feature is their backward-facing pouch, which prevents soil from getting inside while they dig. Though mainly active at dawn, dusk, and night, they may also feed during cool or overcast days. They are rarely seen but leave clear signs of their presence, often treating fences as minor obstacles to go through or under.

One of the most distinctive traits of wombats is their cube-shaped droppings. They use these feces to mark territory and attract mates, and the cubic shape is thought to make them more stackable and less likely to roll, offering a biological advantage. How the wombat produces these cubes is not fully understood, but it is believed the intestine has two flexible and two stiff areas that stretch preferentially. An adult wombat produces 80 to 100 pieces of feces per night, each about 2 centimeters long, with four to eight pieces per bowel movement. In 2019, this phenomenon earned Patricia Yang and David Hu the Ig Nobel Prize for Physics.

All of a wombat's teeth lack roots and grow continuously, similar to rodent incisors. Wombats are herbivores, feeding mostly on grasses, sedges, herbs, bark, and roots. Their incisors are adapted for gnawing tough plants, and like many herbivorous mammals, they have a large gap (diastema) between the incisors and cheek teeth. Their dental formula is 1.0.1.4 / 1.0.1.4 × 2 = 24 teeth. Fur color ranges from sandy to brown, or from grey to black. All three living species average about one meter in length and weigh between 20 and 35 kilograms.

Male wombats have spines on their penis, a non-pendulous scrotum, and three pairs of bulbourethral glands. These glands, along with the testes and prostate, enlarge during the breeding season. Females give birth to a single young after a gestation period of about 20 to 30 days, depending on the species. The young stay in the well-developed pouch for about six to seven months, are weaned by 15 months, and reach sexual maturity at 18 months. Although a group of wombats is sometimes called a wisdom, mob, or colony, they are generally solitary animals. In the wild, they typically live up to 15 years, but can live past 20, and even up to 34 years in captivity. In 2020, biologists discovered that wombats, like many other Australian marsupials, glow under ultraviolet light.

Wombats have an unusually slow metabolism, taking 8 to 14 days to fully digest food, which helps them survive in dry conditions. They move slowly and defend home territories centered on their burrows, reacting aggressively to intruders. The common wombat’s range can be up to 23 hectares, while hairy-nosed species have smaller ranges of no more than 4 hectares. Dingos and Tasmanian devils are predators of wombats, and extinct predators likely included *Thylacoleo* and possibly the thylacine. Their main defense is a toughened rear hide, with much of the posterior made of cartilage. Combined with a lack of a meaningful tail, this makes it hard for a predator following a wombat into its tunnel to bite and injure it. When attacked, the wombat dives into a nearby tunnel and blocks the entrance with its rump. According to an urban legend, wombats may even allow an intruder to put its head over the wombat’s back, then use its powerful legs to crush the predator’s skull.