Wombat
| Family | Vombatidae |
|---|---|
| Species | 3 living |
| Top speed | 40 km/h |
| Output | up to 100 cubes per night |
| Defence | reinforced buttocks |
Wombats are short-legged, muscular quadrupedal marsupials native to Australia, of which there are three living species. They are the only animals known to produce cube-shaped faeces.[1]
Cubes[edit]
A wombat produces between four and eight droppings at each session and up to about 100 in a night, most of them with flat faces and distinct corners.[1] The corners are not formed at the exit. They are formed inside: the last 8% of the intestine has walls of uneven stiffness, with two stiff bands and two flexible ones, so as the drying mass is squeezed rhythmically it is moulded into a square cross-section over several days.[1]
The function appears to be that cubes do not roll. Wombats communicate by leaving droppings on top of rocks and logs at the edges of their territory, which is a delivery problem for a sphere.[2]
Patricia Yang and David Hu were awarded the 2019 Ig Nobel Prize in Physics for this work.[3] The Ig Nobels are given for research that makes people laugh and then think, and the mechanism is the part that makes you think: evolution solved a signalling problem with a manufacturing process.
Rump[edit]
The wombat's rear is a plate of thick skin, cartilage and bone with very little of value behind it. When pursued into a burrow, a wombat blocks the tunnel with it, and can crush an attacking animal's skull against the burrow roof by driving upwards.[4] A predator that follows a wombat home is attacking the single most armoured and least useful part of it, from the least advantageous position available.
Wombats also run at 40 km/h in short bursts, which is faster than Usain Bolt's average over 100 m, and they are built like a footstool.
Species[edit]
| Species | Status | Note |
|---|---|---|
| Common wombat (Vombatus ursinus) | Least concern | The one you have seen |
| Southern hairy-nosed wombat (Lasiorhinus latifrons) | Near threatened | Drier habitat |
| Northern hairy-nosed wombat (Lasiorhinus krefftii) | Critically endangered | Around 300 animals, one main colony |
The last row is the part of this article that is not funny at all.
See also[edit]
References[edit]
- ^ Patricia J. Yang et al., "Intestines of non-uniform stiffness mold the corners of wombat feces", Soft Matter 17 (2021), pp. 475-488.
- ^ Peter Nicholson observations summarised in R. T. Wells, "Vombatidae", in Fauna of Australia vol. 1B (1989).
- ^ Improbable Research, "The 2019 Ig Nobel Prize Winners", Physics.
- ^ Barbara Triggs, Wombats (CSIRO Publishing, 2009), pp. 28-31.