Wombats are completely herbivorous. They are grazers and their diet consists of grasses including snow tussocks for the Bare-nosed or Common wombat, and spear grass for the Southern Hairy-nosed wombat; herbs, roots including roots of grasses, bushes and trees, fungi including mushrooms and puffballs, shrubs, bark, especially the inner bark of certain trees, mosses, leaves, and marsh plants.
Wombats tend to prefer young tender grass shoots when available. Moss also seems to be a favorite food. Bare-nosed wombats will also forage for food along the seashore. Additionally, wombats will sometimes eat farm vegetables.
The Southern hairy-nosed wombat prefers perennial grasses, especially the stipa species. During droughts they may eat bluebush and bindyi.
The Northern Hairy-nosed wombat's favorite grasses are spear grass, tussock grass, and poa grass. They rarely eat weeping grass and reed bent grass.
Bare-nosed wombat eating grass (picture courtesy of Womland used with permission)
During times of drought or shortage, wombats will dig up the dead grass to get the roots.
Since the wombat's diet is nutritionally poor, low in protein and high in fibre, they must conserve as much energy as possible. One of the ways they do this is by having a very low metabolic rate. Southern hairy-nosed wombats have an especially low metabolism. Additionally, wombats have a more efficient digestive system than other grazing animals such as kangaroos, sheep, or cattle.
Relative to its size, the wombat eats very little, only a third as much as a comparably sized kangaroo and a quarter as much as a similar-sized sheep. Since they eat so little, they do not have to spend a great deal of their time foraging.
The Bare-nosed wombat will graze about 3 to 8 hours per night.
The Northern hairy-nosed wombat feeds for about 2 hours each night in the summer, and 6 hours in the winter. An equivalently sized kangaroo feeds for 10 to 18 hours each day. In the wet season, a Northern hairy-nosed wombat's feeding range is about 3 ha (7.5 acres), and in the dry season, it's about 6 ha (15 acres). Northern hairy-nosed wombats prefer the leaves of grasses to the stems which are more nutritious.
A captive Bare-nosed wombat eats a sweet potato (picture courtesy of Womland)
Another source says that the average feeding range of a wombat is about 10-20 hectares (25-37 acres) depending on the quality of the area.
Food passes through a wombat's digestive system slowly, 8 to 14 days, which enables them to extract the maximum amount of nutrients.
Wombats also limit their water loss, so they can go for a long time without drinking water. By staying in their burrow during the heat of the day, they help to conserve water. They require less water than almost any other mammal. They only need about 20% of a sheep's water requirement, and 25% of a kangaroo's.
Because Hairy-nosed wombats live in very dry climates, often the only water they'll get is from the plants they eat. They also get some water from dew. They can go for many weeks, perhaps months, without drinking. After a rain, they tend to drink quite a lot. Bare-nosed wombats, on the other hand, do like to drink frequently.by Peter Marinacci