Tales of wombat "heroes" are unfortunately not true
<p>If you’ve been following the bushfire crisis on social media and elsewhere, you may have seen reports of <a href="https://www.unilad.co.uk/animals/wombats-share-their-burrows-with-animals-displaced-in-bushfires/">benevolent wombats</a> herding other animals to shelter into their fire-proof burrows.</p>
<p>These stories went quickly viral – probably reflecting the appetite for good news after the horrors of the bushfire crisis. However the accounts are not entirely accurate.</p>
<p>Wombats do not heroically round up helpless animals during a bushfire and lead them to safety. But wombats do help other animals in a different way – even if it’s not their intention.</p>
<p><strong>Accidental heroes</strong></p>
<p>Wombats can emerge as accidental heroes during a bushfire, by providing a safe refuge underground for other wildlife.</p>
<p>Wombat warrens – networks of interconnecting burrows – are large and complex, and considerably shielded from the above-ground environment. Small mammals are known to <a href="https://media.australianmuseum.net.au/media/dd/Uploads/Documents/38347/ams370_vXVIII_05_LowRes.ffb19ac.pdf">use wombat burrows</a> to survive an inferno.</p>
<p><a href="https://zslpublications.onlinelibrary.wiley.com/doi/epdf/10.1017/S0952836902001620">One study</a> of the <a href="https://en.wikipedia.org/wiki/Southern_hairy-nosed_wombat">southern hairy-nosed wombat</a>, for instance, found warrens with 28 entrances and nearly 90 metres of tunnels.</p>
<p>What’s more, temperatures deep within burrows are very stable compared to surface temperatures, with daily temperature fluctuations of less than <a href="https://zslpublications.onlinelibrary.wiley.com/doi/epdf/10.1017/S0952836902001620">1℃, compared to 24℃</a> on the surface.</p>
<p>This thermal buffering would help a great deal during intense fires, and you can understand why other species would want access to these safe havens.</p>
<p><strong>The wombat sharehouse</strong></p>
<p>By placing camera traps outside 34 wombat burrows, <a href="http://www.publish.csiro.au/am/am15052">a 2015 study</a> showed a surprising variety of animals using southern hairy-nosed wombat burrows. Researchers observed ten other species, six of which used them on multiple occasions.</p>
<p>The intruders ranged from rock wallabies and <a href="https://www.iucnredlist.org/species/2784/21961179">bettongs</a> to skinks and birds. <a href="https://en.wikipedia.org/wiki/Little_penguin">Little penguins</a> were recorded using burrows 27 times, while the <a href="https://www.iucnredlist.org/species/16751/21955343">black-footed rock wallaby</a> was observed using wombat burrows more often than wombats – nearly 2,000 visits in eight weeks! They were even observed using the burrows to specifically avoid birds of prey.</p>
<p>But wombats aren’t alone in providing real estate for other species. <a href="https://en.wikipedia.org/wiki/Spinifex_hopping_mouse">Hopping mice</a>, <a href="https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:0d4c9c0c-51d3-44e0-a365-fe0f8b791c66">echidnas</a>, <a href="https://en.wikipedia.org/wiki/Eremiascincus">sand swimming skinks</a>, <a href="https://www.ridgeandvalleyreptiles.com/nephrurus-milli.html">barking geckoes</a> and numerous invertebrates <a href="https://www.sciencedirect.com/science/article/pii/S0140196308001821">were found</a> using the warrens of bettongs and bilbies in arid Australia.</p>
<p><strong>Anybody home?</strong></p>
<p>It’s also important to recognise wombats don’t have “a burrow”. Rather, they have <a href="http://www.publish.csiro.au/wr/wr07067">multiple burrows</a> within their <a href="https://en.wikipedia.org/wiki/Home_range">home range</a>. In fact, a 2012 study tracked one wombat to <a href="https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-7998.2011.00881.x">14 different burrows</a>.</p>
<p>While wombats are often regarded as quite sedentary, <a href="https://zslpublications.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-7998.2011.00881.x?casa_token=SiuOr4VY07oAAAAA%3AQNnJyBxVubXbqq27P9j_Z6-fqIsTD0NE1rdU9OGlifTq2v53Ti6eJWPCAc77wljbRgYCzinXHVRiWv_Jyw">another study</a> found the average home range size of common wombats is 172 hectares.</p>
<p>They spend <a href="http://www.publish.csiro.au/zo/ZO02061">a few nights</a> sleeping in one burrow, before moving onto another.</p>
<p>Since each wombat has multiple burrows, many can be vacant within a home range, and <a href="https://www.sciencedirect.com/science/article/pii/S0006320707001048">abandoned burrows</a> are common in some areas. <a href="http://www.publish.csiro.au/wr/Fulltext/WR07067">A 2007 study</a> showed that even among “active” burrows (those with signs of recent use), only one in three are actually occupied by a wombat at any given time.</p>
<p>This means, at times, other species may not need to share burrows with wombats at all. It’s vacant real estate.</p>
<p>So how might a wombat react to an uninvited guest? This is difficult to know, and likely depends on who’s visiting. Wombats prefer not to share burrows with other wombats, although burrow sharing <a href="http://www.publish.csiro.au/zo/ZO02061">can be common</a> when wombat populations are very high in one place.</p>
<p>In her book <a href="https://www.publish.csiro.au/book/6088/">Wombats</a>, Barbara Triggs recalls a fox being chased from a burrow by an angry wombat. Meanwhile, the crushed skulls of foxes and dogs in wombat burrows suggest not all intruders are welcome.</p>
<p>That a suite of species use wombat burrows suggests wombats may not notice or care about squatters – so long as they don’t pose a threat. But more research is needed on the fascinating interactions that take place in wombat burrows, particularly during fire.</p>
<p><strong>The battle is not over</strong></p>
<p>While empirical studies are needed, the available evidence suggests wombats may well provide an important refuge for other wildlife during fire.</p>
<p>In any case, it’s important to recognise that surviving fire is only <a href="https://theconversation.com/animal-response-to-a-bushfire-is-astounding-these-are-the-tricks-they-use-to-survive-129327">half the battle</a>.</p>
<p>Wombats and their house guests face a medley of challenges post-fire – not least avoiding predators in a barren landscape and eking out a living in a landscape with scarce food.</p>
<p><em><a href="https://theconversation.com/profiles/dale-nimmo-15432">Dale Nimmo</a>, Associate professor/ARC DECRA fellow, <a href="http://theconversation.com/institutions/charles-sturt-university-849">Charles Sturt University</a></em></p>
<p><em>This article is republished from <a href="http://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/tales-of-wombat-heroes-have-gone-viral-unfortunately-theyre-not-true-129891">original article</a>.</em></p>
