Little was known about how common wombats (Vombatus ursinus) mate in the wild before the new millennium. These stocky, coarse-haired herbivores, also known as bare-nosed wombats, are mainly nocturnal and live around two thirds of their lives in burrows, so it was generally assumed that mating takes place underground. One night in 1990, researcher Dr. Clive A. Marks, using infrared equipment, filmed the rough-and-tumble courtship between a pair of common wombats mating in an open pasture.
Common wombats reach sexual maturity around 2 years old. Females have more than one estrous cycle in a year; in captivity, they've been observed having a cycle every 32 to 34 days. Estrus -- the period when they're receptive to mating -- lasts for 24 to 81 hours. Wombats generally breed when the perennial grasses they graze on are starting to peak, but they can mate at any time during the year if plenty of food is available. Populations in New South Wales breed mainly between December and March. While in Tasmania, 48 percent of common wombats give birth during October and January. The subspecies Vombatus ursinus urisinus, found on Flinders Island, are seasonal breeders. Their young are born between the middle of January and late August.
Female Calling Cards
The females' cube-shaped scat is covered in pheromones during their estrous cycles. The pheromones are hormonal messages that let any passing male wombats know the females will soon be ready to mate. The females make sure their scat is prominently displayed. If they live close to a number of burrows, several males may be interested and often fight amongst each other. Where burrows are spread out, females sometimes roam from their home ranges, leaving trails of scat for male wombats to find.
A Rough Affair
When Clive Marks videoed a pair of common wombats mating in the wild, courtship began with the male chasing the female as she trotted about, forming circles and figures of eight. Every so often, she would slow down to let the male catch up. After chasing for about 2 minutes, the male gave the female's tough rump a hard bite. The female stopped, and the male held her hindquarters with his forelimbs and rolled her onto her side to mount her. During mating, the female rolled back into a prone position; after several minutes, she broke free. The chasing behavior began again, and the wombats, over 25 minutes, repeated this sequence seven times.
The mating wombats' behavior in Mark's film is the same as an earlier observation, so it's tentatively believed that the behavior is probably typical courtship and mating behavior for common wombats in the wild. Meanwhile, In captivity, a female common wombat was observed attacking the male for about 30 minutes before she allowed mating to take place. The male and female then lay on their sides and mating lasted around 30 minutes.
After Mating Comes Joey
After mating, the males don't have anything to do with the females or their offspring. Common wombats are marsupials; they care for their young, called joeys, in pouches that open toward the females' rumps. This helps to keep their pouches free of dirt when they are digging. Gestation is short, about 22 days; at birth, each underdeveloped newborn -- the size of a jellybean, hairless and blind -- crawls out of the mothers' birth canal and into the pouch to attach onto a teat. Despite having two teats, common wombats give birth to only one joey. The juvenile lives in the mother's pouch for about six months and may stay with the mother, outside the pouch, until 18 months old. Because the young are dependent for so long, female common wombats probably mate only every two years.
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