Northern hairy-nosed wombat
|Northern hairy-nosed wombat|
|Northern hairy-nosed wombat range|
The northern hairy-nosed wombat (Lasiorhinus krefftii), is one of three species of wombats. It is one of the rarest large mammals in the world and is critically endangered. Its historical range extended across New South Wales, Victoria, and Queensland as recently as 100 years ago, but it is now restricted to one place, a 3-km2 range within the 32-km2 Epping Forest National Park in Queensland. In 2003, the total population consisted of 113 individuals, including only around 30 breeding females. In the last census taken in 2010 there was found to be an estimated population of 163 individuals, and in recent years the species seems to be following the trend of a slow but steady increase.
In general, all species of wombats are heavily built with large heads and short powerful legs. They have strong claws to dig their burrows, where they live much of the time. It usually takes about a day for an individual to dig a burrow.
Northern hairy-nosed wombats have bodies covered in soft, grey fur and even have fur on their noses, a trait that sets them apart from the common wombat. They have longer, more pointed ears and a much broader muzzle than the other two species. Individuals can be 35 cm high, up to 1 m long and weigh up to 40 kg. The species exhibits sexual dimorphism, with females being somewhat larger than males due to the presence of an extra layer of fat. They are slightly larger than the common wombat and able to breed somewhat faster (giving birth to two young every three years on average).
The northern hairy-nosed wombat's nose is very important in its survival because it has very poor eyesight, so it can easily detect its food in the dark through smell.
The Northern hairy-nosed wombat is nocturnal, living underground in networks of burrows. They avoid coming above-ground in harsh weather conditions because the burrows maintain a constant humidity and temperature threshold. They have been known to share burrows with up to 10 individuals, equally divided by sex. Young are usually born during the wet season between November and April. In years with a lot of rainfall, 50-80% of the females in the population will breed, giving birth to one offspring at a time. Juveniles stay in the mother's pouch for 8 to 9 months and are weaned at 12 months of age.
Northern hairy-nosed wombats do not have to feed every day because they have such a low metabolic rate that allows them to sustain themselves off energy reserves in the body for extended periods of time. Even when they do feed every day, it is only for 6 hours a day in the winter and 2 hours in the summer, significantly less than a similar-sized kangaroo that must feed for at least 18 hours a day. Their diet consists of native grasses (black speargrass (Heteropogon contortus), bottle washer grasses(Enneapogon spp.), golden beard grass (Chrysopogon fallax), and three-awned grass(Aristida spp.) as well as various types of roots. One trait that makes this species unique is their teeth grow throughout their lifetime, so older individuals can eat just as efficiently as younger individuals. Its habitat has become infested with African buffel grass, which outcompetes the native grasses on which the wombat prefers to feed.
The genus name Lasiorhinus comes from the Latin words lasios, meaning hairy or shaggy, and rhinus, meaning nose. The widely accepted common name is Northern hairy-nosed wombat, based on the historical range of the species as well as the fur, or "whiskers", on its nose. In some older literature it is referred to as the Queensland hairy-nosed wombat.
The Northern hairy-nosed wombat shares its genus with one other extant species, the Southern hairy-nosed wombat. The common wombat, is in the Vombatus genus. Both Lasiorhinus species differ morphologically from the common wombat by their silkier fur, broader hairy noses, and longer ears.
Placental and marsupial mammals are an example of divergent evolution, an evolutionary concept occurring when a single group of organisms splits into two groups and each group evolves in different directions. The wombat, with all marsupials, diverged from placental mammals during the Cretaceous. The koala is the most closely related marsupial to wombats and is categorised in the same suborder, Vombatiformes.
Threats to the Northern hairy-nosed wombat include small population size, predation, competition for food, disease, floods, droughts, wildfires, and habitat loss. Having such small population sizes makes the species especially vulnerable to natural disasters. Wild dogs are probably the wombat's number one predator. The habitat at Epping Forest National Park is now well-protected to ensure better chances of survival.
Due to these threats, the Northern hairy-nosed wombat is listed as "endangered" by the Australian Species Profile and Threats Database (SPRAT), and "critically endangered" by the IUCN. Its range is restricted to about 300 ha (750 acres) of the Epping National Forest in East-Central Queensland, 120 km northwest of Clermont.
To combat the vulnerability of this species, there have been a number of conservation projects put into action over recent years. One example was the construction of a two-metre-high, predator-proof fence around 25 km2 of the park in 2000. Recently, a second population of wombats has been established at Richard Underwood Nature Refuge at Yarran Downs near St. George in Southern Queensland. This second population was established in 2008 and is also in a reserve surrounded by a predator-proof fence. Within Epping Forest National Park, there have been increased attention and funds for wombat research and population monitoring, fire management, maintenance of the predator-proof fence, general management and control of predators and competitors, and elimination of invasive plant species.  In addition, the species recovery plan of 2004 to 2008 includes communication and community involvement in saving the species and works to increase the current population in the wild, establish other populations within the wombat's historical range, and work with zoos to establish a captive husbandry program. There is also a volunteer caretaker program that allows volunteers to contribute in monitoring the population and keeping the predator fence in good repair. Finally, DNA fingerprint identification of wombat hairs allows research to be conducted without an invasive trapping or radio tracking program. Due to the combined efforts of these forces, the Northern hairy-nosed wombat population is slowly making a comeback.
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