Wombat: Difference between revisions

| title = 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 [[marsupial]]s native to Australia, of which there are three living species. They are the only animals known to produce cube-shaped faeces.<ref name="yang">Patricia J. Yang et al., "Intestines of non-uniform stiffness mold the corners of wombat feces", ''Soft Matter'' 17 (2021), pp. 475-488.</ref>

== Cubes ==

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.<ref name="yang" /> 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.<ref name="yang" />

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.<ref>Peter Nicholson observations summarised in R. T. Wells, "Vombatidae", in ''Fauna of Australia'' vol. 1B (1989).</ref>

Patricia Yang and David Hu were awarded the 2019 [[Ig Nobel Prize]] in Physics for this work.<ref>Improbable Research, "The 2019 Ig Nobel Prize Winners", Physics.</ref> 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 ==

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.<ref>Barbara Triggs, ''Wombats'' (CSIRO Publishing, 2009), pp. 28-31.</ref> 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 ==

{| class="wikitable"

|+ Living species

! 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 ==

* [[Ig Nobel Prize]]

* [[Platypus]]

[[Category:Animals]]

[[Category:True but improbable]]