The Northern Hairy-nosed Wombat, Lasiorhinus krefftii, is one of the world's most critically endangered species. It is the largest herbivorous burrowing mammal in the world and disappeared rapidly after the introduction of sheep, cattle and rabbits into Australia, due to competition for grass (their nutrition is based on almost 100% grass).At one time, their number fell to an all-time low of just 30 individuals! Earnest preservation activities at the Epping Forest National Park have helped the Wombat recover its population, thanks to installation of fences that keep domesticated animals from entering. In 2000-01, dingoes killed up to 20 Northern hairy-nosed wombats. This necessitated building a 20 km dingo-proof fence around all wombat habitat in Epping, home of the last population.