A wombat emerging from a sandy burrow in heathland on the South Coast. Photo: Ian Fraser.
In recent days, wombats have been in the news for the wrong reasons, but it’s not that it’s been their fault!
There’s no need to revisit that sad and sorry saga with the social influencer, but it’s a good excuse to offer a column on these wonderful and often abused old Australians.
Common (or Naked-nosed) Wombats are indeed common in our part of the world and are increasingly sighted within or alongside suburban Canberra, far more often than I can recall from 30 or so years ago. This is partly because Canberra has expanded so widely in those years, but the wombats do seem to have spread too, so most of Canberra Nature Reserve and the river corridors (especially the Molonglo downstream of the Tuggeranong Parkway) have multiple wombat records.
Given the number of dead wombats along surrounding roadsides, particularly the road through Braidwood to the coast, plus the fact that a female wombat has only one youngster every second year, I’m often surprised at how common they still are.
Common Wombats are one of three living wombat species, the other two being arid and semi-arid land animals from South and Western Australia and Queensland, respectively. Their ancestors branched off from other Australian mammals at least 25 million years ago and their closest relations are Koalas, which later went their own way and took to the trees.
Wombats are notoriously solitary animals, except for mothers accompanied by offspring and brief encounters for mating. Otherwise, they behave aggressively towards other wombats they encounter and avoid them where possible, using piles of distinctive cube-shaped droppings to exchange information, including, it seems, the dominance or otherwise of the depositor.
However, they are most famous for their remarkably industrious burrowing, which seems to be a lifelong vocation. Young wombats are known to work on the burrow, practising, in fact, while their mothers doze. But it’s not just one burrow by any means. The territory is dotted with ‘minor’ burrows up to five metres deep, which are convenient bolt holes in emergencies and a convenient ‘crash pad’ at other times. All this soil-moving also provides a valuable ecological function in aerating soil and promoting plant growth, as well as providing shelter for a range of other animals.
I am convinced that many lyrebirds survive intense fires by sheltering in wombat burrows.
The wombat’s flattened rump and head, powerful digging feet and small ears are all visible here. Photo: Ian Fraser.
Despite their generally anti-social nature, territories may overlap, and in this situation, more than one wombat may use the same burrow, though rarely at the same time. A pile of fresh droppings by the burrow is an unambiguous Occupied sign.
A wombat may visit up to six of these burrows in the course of a night’s activities, presumably checking on their condition and doing such maintenance as may be required. Some wombats have been recorded visiting up to 20 different burrows over a few weeks. Then there are likely to be two or three ‘major’ burrows, each up to 20 metres long with branched tunnels, sleeping chambers lined with grass or leaves and multiple entrances. They may even eventually connect up with another such burrow.
Wombats dig with powerful legs and broad feet with flat, hard claws, using the flattened rump and even its head to compact the walls and ceiling. Hard soil is no barrier to a wombat, and even boulders may be shoved aside.
Their primary food comprises tough, fibrous native grasses, which they nip off with their sharp incisors and chew up with hard-ridged molars. Such a diet inevitably wears these teeth down, but to compensate, a wombat’s teeth grow constantly throughout their lives, like a rodent’s teeth or a cocky’s bill.
Mostly, and especially in summer, they are nocturnal, but in cold weather, they may feed during the day and take breaks in a convenient minor burrow.
A well-defined wombat track across Bogong Swamp in Namadgi National Park. Constant use keeps the ground compacted and the grass clear for easy year-round access. Photo: Ian Fraser.
Wombats are highly adaptable. They are one of the few animals to remain active all year round, high in the snow country, but are also found right down to the coastal heaths.
A wombat’s pouch opens backwards, presumably to keep the dirt out while in the burrow, and especially while excavating. The baby wombat spends up to 10 months entirely within the pouch, then follows its mother around for most of the next year, gradually weaning itself onto the grass diet, which is its lot for the rest of its life.
After two years, it is banished into a solitary life in the wider world where, if it can avoid cars, drought, angry farmers and deranged social influencers, it may live for more than 10 years.
Ian Fraser is a Canberra naturalist, conservationist and author. He has written on all aspects of natural history, advised the ACT Government on biodiversity and published multiple guides to the region’s flora and fauna.
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