Well, Mr. Oatmeal is apparently repeating an urban legend. I look at a wombat, and no way do I believe that thing can move at 25 mph (40 kph). I found a piece[0] which indicates this might have been some confusion as to metric vs imperial decades ago that was then retransmited through the ages.
[0] https://www.abc.net.au/news/science/2024-04-13/how-fast-can-...
And yet the very article that you refer to confirms that anecdotal reports by the biologists studying these very animals report that during breeding seasons that the male Southern Hairy-Nose Wombat can reach these speeds in bursts:
>South Australian wildlife biologist [A/Prof] David Taggart has studied the southern hairy-nosed wombat since 1993. In the 2008 and 2024 editions of Strahan's mammal book, he writes that the southern hairy-nosed species can run at 40 kph. "I can confirm that I have clocked this species running at just over 40 kph, although they can't maintain that for long."
More non-peer reviewed information here from the Australian national science agency: https://connectsci.au/news/news-parent/3758/Turns-out-wombat...
We have four on the boundaries of our property. My 'Goldidor' (Labrador/retriever cross) has given chase a few times and has struggled to keep up. When they run they RUN. Maybe not pushing 40kph, not not far from it...