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In the wake of the devastating bushfires currently burning in Australia, an image has been widely shared on social media:

greenpeacenz: Reports from Australia that countless small animals have escaped death because wombats, unusually, opted to share their massive, complex burrows. Even reports that they have been observed exhibiting "shepherding behavior".

Here is one example from Twitter, retweeted 11K times:

While I have an open mind, I am suspicious for three reasons:

  • It is hard to imagine how this behaviour would evolve.
  • It is hard to imagine any animal behaviourist having the time to carefully observe wombats during a bushfire, and I don't trust the wishful observations from non-experts.
  • The spelling of "behavior" is American - but then again, "sheperding" is a misspelling too.

Have there been reliable reports of shepherding and sharing of burrows? I will accept evidence from outside of this bushfire season. (e.g. I can imagine an biologist preparing an experiment before a planned hazard-reduction burn.)

Oddthinking
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  • They share burrows, yes, not just because of fire: https://pursuit.unimelb.edu.au/articles/a-wombat-a-koala-and-a-rabbit-in-a-burrow – bishop Jan 13 '20 at 02:44
  • And this is behavior field biologists study, because it seems counterintuitive: https://bioone.org/journals/mammal-study/volume-43/issue-3/ms2017-0062/Interspecific-Burrow-Sharing-between-Mammals-in-Countryside-in-Japan/10.3106/ms2017-0062.pdf – bishop Jan 13 '20 at 02:45
  • @bishop: Your first link is clear that the wombat **would not** "share" - it would have chased out the koala if it had noticed. The second link says the same about badgers: "Therefore, the mammals engaged in interspecific burrow sharing are likely to exhibit temporal differentiation." That is, they don't use the same burrow at the same time. – Oddthinking Jan 13 '20 at 02:56
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    Sure, under normal circumstances, where the wombie is active at night. During fires, however, they go dormant in their resting chambers, which are [at the very back of their burrow and essentially fireproof](https://www.wombania.com/wombats/wombat-burrows.htm). Whilst in there, they are not coming out, they're dug in so to speak. Other animals very likely come into the fore chambers of these burrows and avail themselves of the shelter. It's not altruistic, it's just a giant hole (wombies are quite large) that's available and the owner's not interested in defending at that time. – bishop Jan 13 '20 at 04:59
  • http://www.publish.csiro.au/am/am15052 Again, co-use is normal, to the extent that the wombat's present and accepting of the cohabitor. Given burrowing creatures do not go out during fires, it seems likely burrow owner's wouldn't be evicting cohabitors. Not altruism, as the link makes it out. – bishop Jan 13 '20 at 05:11
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    @Bishop: Would you like to post an answer based on that? – Oddthinking Jan 13 '20 at 07:31

1 Answers1

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Yes, they do share... but not specifically because of the fires or out of a sense of altruism.

According to AFP Fact Check:

University of Adelaide ecologist Dr. Michael Swinbourne told AFP via email on January 16, 2020: “Wombats will share their burrows with other animals at the same time. I wouldn't say that wombats are "happy" about sharing with other animals, but they will "tolerate" them as long as they don't disturb the wombat too much.

Further:

Dr. Swinbourne says: “Wombats definitely do not shepherd other animals into their burrows. It is possible that this idea arose because someone saw an animal either follow a wombat into its burrow, or the other animals went in first followed by the wombats.

Original answer

I do believe sharing is plausible based on published observations of wombat behavior. Here's what we know:

I believe these facts lend credence to this scenario:

  1. As fire approaches, bush animals begin retreating
  2. The wombat retreats to its burrow, "digs in", and prepares to wait out the fire
  3. Other animals observe the wombat retreat and follow it
  4. Since the wombat is dug in, it does not attempt to evict the interlopers

To an outside observer, this might appear as though the wombat is "shepherding" other animals in. It might also appear unusual that the wombat isn't evicting. But, in reality, the wombat is making a defensive stance and ignoring all other considerations. There's no altruism involved.

Wombats, being nocturnal and resident in remote areas, are not well studied in ideal scenarios. The most thorough study of wombat burrows was performed in 1960 by 15-year old Peter Nicholson! To think their behavior has been well-studied in life-threatening bush fire conditions is, unfortunately, not realistic.

The Conversation has published a similar analysis to the above.

bishop
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    A very well researched answer that gives a more plausible explanation than wombats being the Noah of the animal kingdom. – Jordy Jan 15 '20 at 06:41
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    Also wombats have multiple burrows across their range, so many of the burrows will be vacant at any given time. Another good summary article is https://www.abc.net.au/news/2020-01-15/australian-bushfires-wombat-heroes-have-gone-viral/11868808 – Jack Jan 15 '20 at 22:45