Do wombats share their burrows during fires?

Question

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

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.)

Answer 1

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.

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Original answer

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

• Wombats are large animals
• Wombat burrows are enormous, spacious, and well-established: they can be observed from space, have many branching tunnels and may survive for upwards of 50 years
• Wombat burrows are fire-proof
• Wombats, when threatened, retreat to the inner most chamber, turn their back toward the entrance, and do not leave
• Wombats have been observed sharing burrow with other species in normal circumstances

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.