minor inconveniences to be gone through or under. Wombats leave distinctive cubic feces. As wombats arrange these feces to mark territories and attract mates, it is believed that the cubic shape makes them more stackable and less likely to roll, which gives this shape a biological advantage. The method by which the wombat produces them is not well understood, but it is believed that the wombat intestine stretches preferentially at the walls, with two flexible and two stiff areas around its intestines. The adult wombat produces between 80 and 100, pieces of feces in a single night, and four to eight pieces each bowel movement. In 2019 the production of cube-shaped wombat feces was the subject of the Ig Nobel Prize for Physics, won by Patricia Yang and David Hu. Wombats are herbivores; their diets consist mostly of grasses, sedges, herbs, bark, and roots. Their incisor teeth somewhat resemble those of rodents (rats, mice, etc.), being adapted for gnawing tough vegetation. Like many other herbivorous mammals, they have a large diastema between their incisors and the cheek teeth, which are relatively simple. The dental formula of wombats is . Wombats' fur can vary from a sandy colour to brown, or from grey to black. All three known extant species average around in length and weigh between . Female wombats give birth to a single young after a gestation period of roughly 20–30 days, which varies between species. All species have well-developed pouches, which the young leave after about six to seven months. Wombats are weaned after 15 months, and are sexually mature at 18 months. A group of wombats is known as a wisdom, a mob, or a colony. Wombats typically live up to 15 years in the wild, but can live past 20 and even 30 years in captivity. The longest-lived captive wombat lived to 34 years of age. In 2020, biologists discovered that wombats, like many other Australian marsupials, display bio-fluorescence under ultraviolet light. Ecology and behaviour Wombats have an extraordinarily slow metabolism, taking around 8 to 14 days to complete digestion, which aids their survival in arid conditions. They generally move slowly. When threatened, however, they can reach up to and maintain that speed for . Wombats defend home territories centred on their burrows, and they react aggressively to intruders. The common wombat occupies a range of up to , while the hairy-nosed species have much smaller