Wombat Conservation Project
Steve Irwin and the Australia Zoo team love wombats. It's as simple as that. Why else would you build a one-acre enclosure with large air-conditioned dens and then put just three Common Wombats in it? The Australia Zoo wombats have the best life of any captive wombat anywhere in the world. Almost to prove the point, both of our females have produced offspring in the last two years despite being hand-raised, something that usually prevents breeding in captivity. Their offspring, two female joeys, have also been hand-raised and now share time in the enclosure with their parents. Given that the new enclosure has only had wombats in it for 30 months, the enclosure and husbandry regimes have been enormously successful.
The experience of caring for the adults and producing these Common Wombat joeys has just been the start of an ambitious program by Australia Zoo to aid the critically endangered Northern Hairy-nosed Wombat.
The Northern Hairy-nosed Wombat is one of the most endangered species of mammal in the world. There are currently no more than 113 individuals left in the wild, and this is an ambitious guess based upon random hair-sampling of active burrows. At one point in the 1970s it was thought that the population was as low as 35 individuals, so there has been some progress in stabilising the population.
This species was only ever known to exist in three locations - Jerilderie in western New South Wales, around St. George in south-west Queensland and at Epping Forest near Clermont in central Queensland. Today they are only found in an area that consists of 300 hectares of bush in Epping Forest National Park, having become extinct in the other locations in the early part of last century.
Northern Hairy-nosed Wombats have only ever once been brought into a controlled captive environment; a zoological facility in New South Wales in the mid 1990s. Unfortunately this single male animal passed away after a short period, so there was little learned from the time it was cared for. Given how few Northern Hairy-nosed Wombats there are, Australia Zoo has started a husbandry program on the more common Southern Hairy-nosed Wombat.
The Southern and Northern Hairy-nosed Wombats are genetically much more closely related to each other than either of them are to the Common Wombat. They show many similar traits in their life history, and both are specialists in their habitat selection. Both species live in semi-arid areas where the rainfall is sporadic, the summers long and hot and where nighttime temperatures can plummet below zero. Tough for any species to survive, but when you add that usually neither species has access to free standing water, it's easy to see that these animals have to be specialists to survive. The secret to their survival is a combination of behaviour, habitat selection and physiology. Hairy-nosed wombats have an incredibly low metabolic rate and a digestive system that is incredibly slow, allowing every tiny bit of moisture to be absorbed from their food. The behaviour to conserve moisture is simply to spend most of their lives resting below ground, away from hot temperatures. In summer these animals may only spend an hour or so above ground in the cool hours before dawn. Where both species become highly specialised and why historically they never had wide distributions, is in the selection of the soil that they choose to dig a burrow.
Both species live in sandy soil; however, a burrow in pure sand would not be stable and would cause the animals to dehydrate. So hairy-nosed wombats dig in areas and make burrows in sandy soils that will remain humid, so reducing moisture loss. For the Northern Hairy-nosed Wombat, this means digging burrows along old creek beds or dunes that have a certain clay component to hold moisture. For the Southern Hairy-nosed Wombat, animals make burrows under layers of soft rock that is floating in the sandy soils. Wombats will dig right through this rock, as a burrow formed under the rock will retain a much higher humidity.
As part of the Australia Zoo wombat conservation program, we have obtained five orphaned Southern Hairy-nosed Wombats from a property in South Australia that was under extreme drought and has had an estimated 80% decline in its adult wombat population. The five animals being raised were all obtained in March 2004 and were varied in their size and age.
Clare Gover is playing 'mum' to these wombats and is raising all five animals together. Clare has a wealth of experience in raising marsupials and is a natural born mother.
The five little wombats have all been named and are pictured below.
Australia Zoo has developed an ambitious four-stage plan for these Southern Hairy-nosed Wombats.
- Collect and transport the animals successfully - done!
- Raise as many to independence as possible -
- Successfully establish the animals onto a captive diet; and
- Display and trial soft release programs.
So far, stage one has been successfully completed and stage two is well on its way. Knowledge from this transportation and raising is already being collated and has been used by researchers in South Australia.
Australia Zoo has a great interest in the conservation of all three species of wombat, a group of animals found nowhere else in the world. The Zoo has already bred and hand-raised the Common Wombat and is now working on the Southern Hairy-nosed Wombat. This knowledge will greatly aid the conservation of these two species, and it will no doubt help develop skills that can be used to assist the survival of the Northern Hairy-nosed Wombat