Wombat burrows are elaborate underground tunnel systems that function as climate-controlled shelters, protecting the world’s largest burrowing marsupials from temperature extremes, predators, and bushfires. A single burrow can extend dozens of meters in length, with multiple entrances and chambers dug into soil and rock. All three living species of wombat dig burrows, but how they use them, and how those burrows ripple outward to reshape entire ecosystems, makes the subject richer than the hole in the ground might suggest.
Scale and Structure
Common wombats (also called bare-nosed wombats) typically dig burrows that range from a few meters to roughly 20 meters long, though some sprawling tunnel networks stretch much further. Depth varies by terrain and soil type, and recent research using ground-penetrating radar has confirmed that even within the same species, burrow depth can differ between populations. A study of critically endangered northern hairy-nosed wombat burrows found that tunnels at one nature refuge were shallower in both maximum and mean depth compared to those at another long-established site, likely reflecting differences in soil conditions and colony age.1Australian Mammalogy. Non-invasive mapping of critically endangered northern hairy-nosed wombat (Lasiorhinus krefftii) burrows using ground-penetrating radar: a case study at Richard Underwood Nature Refuge
The two hairy-nosed species, the southern and the critically endangered northern hairy-nosed wombat, tend to build more complex communal warrens with numerous interconnected tunnels and multiple openings, sometimes shared by a dozen or more animals. Common wombats, by contrast, generally maintain simpler burrow systems, but they still dig multiple burrows across their home range and rotate among them. Burrow entrances are typically wide enough for a wombat to squeeze through and not much wider, which helps exclude larger predators. The tunnel cross-section is often roughly the same width as the wombat itself, creating a tight, defensible space.
Temperature Control Underground
The primary survival advantage of a burrow is thermal buffering. While surface temperatures in the Australian outback can soar past 45°C in summer and plummet near freezing on winter nights, burrow interiors stay remarkably stable. Research modeling resting wombats at six sites across Australia found that burrows are essential for reducing the energy a wombat spends heating or cooling its body and for cutting water loss. In semi-arid areas with no shade, burrows can mean the difference between surviving the hottest months and dying of heat stress.2International Journal for Parasitology: Parasites and Wildlife. Environmental suitability of bare-nosed wombat burrows for Sarcoptes scabiei
Depth matters, but not always in the direction you might expect. Deeper burrows offer greater energy savings during cold seasons because they insulate against frigid surface temperatures. During hot seasons, though, shallower burrows actually provided lower thermoregulatory costs. The researchers found no clear evidence that extreme heat stress inside burrows has worsened over the study period due to climate change, but shallow burrows in one year were frequently predicted to expose wombats to heat stress, having rarely been flagged for it in earlier decades.3PubMed Central. Seasonal and depth-dependent thermoregulatory benefits of burrows for wombats – The largest burrowing marsupials
Breathing in a Sealed Tunnel
Living underground presents an obvious problem: the air gets stale. Oxygen drops and carbon dioxide builds up, especially in long, narrow tunnels with limited ventilation. Wombats have evolved a remarkably tolerant respiratory system to deal with this. When researchers exposed common wombats to progressively lower oxygen levels, the animals increased their breathing rate but did so in a blunted way compared to surface-dwelling mammals. Even at oxygen concentrations as low as 8%, their hyperventilation response was only about 1.85 times their resting rate, and they shifted into a lower metabolic gear only at the most extreme levels.4PubMed. Ventilation and metabolism in a large semifossorial marsupial: the effect of graded hypoxia and hypercapnia
This muted response is thought to reflect an evolutionary adaptation to spending long stretches underground where oxygen is chronically lower than at the surface. An animal that panicked and hyperventilated aggressively in response to stuffy burrow air would waste energy and dehydrate faster. The wombat’s strategy is essentially to stay calm, breathe a bit more, and slow down its metabolism when things get tight. It is an elegant solution for an animal that may spend 16 or more hours a day inside a tunnel.
Burrow Sharing and Switching
Wombats are generally solitary, but their burrows are not strictly private. Tracking studies have found that each active burrow is used, on average, by about 2.2 different individuals. A wombat typically sleeps in the same burrow for one to four days and then moves to a different one within its home range.5Wildlife Research. Home range, burrow-use and activity patterns in common wombats (Vombatus ursinus)
This pattern of rotating through burrows has several consequences. It distributes wear and maintenance across multiple tunnels rather than concentrating it in one. It gives parasites and pathogens less time to accumulate in one spot before the occupant leaves. And it means that at any given time, a landscape dotted with wombat burrows includes plenty of unoccupied tunnels, which turn out to be critically important for other species.
Reshaping Soil and Vegetation
A wombat does not just dig a hole; it rearranges the landscape. The sheer volume of soil displaced by a wombat colony over years creates mounds, depressions, and altered drainage patterns. Studies in alpine Tasmania found that burrow mounds, which wombats commonly use as latrines, were substantially higher in nitrogen than surrounding undisturbed ground or the paths wombats wore into the landscape. The nitrogen enrichment from wombat dung concentrated on these mounds alters what grows there, creating patchwork differences in vegetation composition. Researchers estimated that common wombats directly affected at least 1.2% of the study area through their digging, grazing, and defecation.6Austral Ecology. Environmental associations and effects of disturbances by common wombats in alpine Tasmania
Beyond surface soil changes, wombat digging modifies how water moves through the landscape. Burrows and the disturbed soil around them increase water infiltration, pulling rainfall down into the ground rather than letting it run off the surface. This changes erosion patterns and affects the chemical properties of deeper soil layers, which in turn can promote seed germination in the disturbed zones around burrow entrances.7Oxford Academic (Journal of Mammalogy). Wombat burrows are hotspots for small vertebrates in a landscape subject to gigafire The cumulative effect of thousands of burrows across a landscape makes wombats genuine ecosystem engineers, animals whose physical modifications to their environment create or maintain habitat for other species.
Refuge from Bushfire
Australia’s catastrophic 2019–2020 bushfire season drew attention to an overlooked function of wombat burrows: they serve as fire shelters for other animals. Research following those fires found that common wombat burrows predominantly supported native species and that some native animals increasingly used burrows as fire severity increased. The species found sheltering in wombat burrows tended to be smaller, suggesting the tunnels are especially important for animals that cannot outrun a fire front and need a place to hide until the danger passes.8Charles Sturt University. The impact of the 2019–2020 wildfires on terrestrial species in forests of south-eastern Australia
Camera-trap surveys at burrow entrances have recorded a wide variety of visitors: small marsupials, lizards, echidnas, rabbits, and various invertebrates. The cooler, more humid air underground protects animals not only from direct flame but also from the lethal radiant heat and smoke that kill many surface-dwelling creatures even when fire does not burn their exact location. In a landscape increasingly shaped by megafires, the sheer density of wombat burrows may function as a dispersed network of survival refuges that boosts the resilience of entire small-animal communities.
The Mange Problem
The same features that make burrows excellent shelters also make them incubators for disease. Sarcoptic mange, caused by the burrowing mite Sarcoptes scabiei, is the most serious health threat facing bare-nosed wombats across much of their range. The stable temperature and high humidity inside a wombat burrow are nearly ideal for keeping these mites alive off the host animal. Research measuring conditions inside burrows estimated that mites could survive an average of about 16 days in winter, far longer than the four to ten days a wombat typically spends in one burrow before switching to another.9International Journal for Parasitology: Parasites and Wildlife. Environmental suitability of bare-nosed wombat burrows for Sarcoptes scabiei
This mismatch creates a clear transmission pathway. Wombat A leaves mites in a burrow. Wombat B moves in a few days later and picks them up, even though the two animals never met face to face. In summer, when burrow air is warmer and drier, off-host mite survival drops to roughly six days, which helps explain why mange transmission tends to peak in colder months. The phenomenon is called asynchronous burrow sharing, and it is now considered a major mechanism by which mange spreads through wombat populations.
Landscape-level analysis has added another dimension to the problem. Modeling of mange occurrence in bare-nosed wombats found a negative association between mange and the proportion of remnant native vegetation: wombats living in areas with less remaining native habitat appeared to have higher rates of mange. There was also a weak positive trend suggesting that more active burrows per wombat was associated with higher mange prevalence, possibly because more burrows create more opportunities for indirect contact.10PubMed Central. Fine-Scale Landscape Epidemiology: Sarcoptic Mange in Bare-Nosed Wombats (Vombatus ursinus) Interestingly, raw wombat density and burrow density alone were not strong predictors of mange, suggesting the disease’s spread depends more on habitat fragmentation and behavioral patterns than simply on how many wombats are packed into an area.
How Burrowing Evolved
The fossil record shows that wombats have not always been burrowers. The debate over when and how burrowing originated in the wombat family goes back to the nineteenth century, when paleontologists discovered remains of enormous extinct wombats and wondered whether animals that large could possibly have dug tunnels. The emerging consensus is that the largest ancestral wombats did not burrow. Researchers have argued that the biggest species, like Phascolonus gigas, faced physical and physiological limitations that would have made true burrowing impractical at their size, and that burrowing likely originated in an ancestor weighing roughly 20 to 40 kilograms, similar in mass to modern species but currently unrepresented in the fossil record.11Mammal Review. The palaeoecology of the Vombatidae: did giant wombats burrow?
The 2020 discovery and description of Mukupirna, a 25-million-year-old marsupial from central Australia that weighed over 100 kilograms, shed further light on this question. Mukupirna had forearm adaptations commonly seen in digging animals, suggesting it used scratch-digging to access underground food like roots and tubers. But it lacked a specialized feature found in all modern wombats: a modified deltopectoral crest that creates an enclosed tunnel-like groove for a key arm muscle used in powerful burrowing. Its large size, combined with the absence of this feature, suggests Mukupirna was a digger but not a true burrower.12Scientific Reports. A new family of diprotodontian marsupials from the latest Oligocene of Australia and the evolution of wombats, koalas, and their relatives (Vombatiformes) Another interesting detail: Mukupirna lacked the continuously growing molars that are a hallmark of living wombats, which means the skeletal adaptations for digging came first in evolutionary time and the dental specializations followed later.
Examination of other early wombat relatives has reinforced the idea that scratch-digging for food was the transitional stage between surface life and full burrowing. Evidence from primitive wombat forelimb bones suggests a root-eating niche for at least some of these early species, animals that dug not to create homes underground but to access buried food sources.13UNSWorks. Palaeontology of primitive wombats Over millions of years, what started as foraging behavior appears to have deepened, literally, into the construction of permanent shelters.
Surveying Burrows in the Modern Landscape
Counting and mapping wombat burrows is harder than it sounds. Burrow entrances can be hidden under tussock grass, collapsed, or partially obscured by vegetation. Traditional ground surveys require researchers to walk systematic transects, visually identifying each hole, which is labor-intensive and limited by terrain access. Drone-based surveys have emerged as a promising alternative. In one study comparing the two methods, a total of 204 individual burrows were recorded across drone and ground surveys combined. In open grassland, both approaches detected similar numbers of burrows. In denser tussock grassland, however, ground surveys found more burrows because overhanging grasses concealed the entrances in aerial images.14PubMed Central. Mapping out bare-nosed wombat (Vombatus ursinus) burrows with the use of a drone
For understanding what lies beneath the surface, ground-penetrating radar offers a way to trace tunnel paths without disturbing the soil. Recent advances in the technology have allowed researchers to map the three-dimensional layout of northern hairy-nosed wombat burrows at a nature refuge, comparing burrow depths between populations at different sites.15Australian Mammalogy. Non-invasive mapping of critically endangered northern hairy-nosed wombat (Lasiorhinus krefftii) burrows using ground-penetrating radar: a case study at Richard Underwood Nature Refuge For a critically endangered species with fewer than 400 individuals left in the wild, non-invasive methods like these are essential. You cannot excavate a burrow to study it when doing so might destroy the home of an animal whose entire species depends on a handful of colonies.
Wombats and Cultural Landscape
Wombats are culturally important to Aboriginal Australians, who have observed and lived alongside these animals for tens of thousands of years. Across various Aboriginal language groups, wombats feature in creation stories, place names, and traditional ecological knowledge that predates Western scientific study by millennia.16Annual Reviews. The Distinctive Biology and Characteristics of the Bare-Nosed Wombat (Vombatus ursinus) Indigenous knowledge systems recognized wombats as landscape-shaping animals long before ecologists coined the term “ecosystem engineer.” The growing integration of Indigenous ecological knowledge into wombat conservation is one of the more encouraging developments in the field, particularly for managing the northern hairy-nosed wombat, whose surviving colonies sit on land with deep Aboriginal cultural connections.
On the less harmonious side of human-wombat coexistence, burrows regularly come into conflict with agriculture and infrastructure. Farmers have long complained about wombat holes damaging fences, undermining road shoulders, and creating hazards for livestock and machinery. In some regions, permits to destroy burrows or cull wombats have been issued, though attitudes have shifted as the ecological value of burrows has become clearer. The tension is real, though: a wombat’s idea of prime burrowing real estate and a farmer’s idea of productive pasture frequently overlap, and managing that conflict without decimating wombat populations remains an ongoing challenge across southeastern Australia.