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.
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.
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:
- As fire approaches, bush animals begin retreating
- The wombat retreats to its burrow, "digs in", and prepares to wait out the fire
- Other animals observe the wombat retreat and follow it
- 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.