This nocturnal and generally solitary marsupial feeds on various grasses. It spends the day inside burrows, and creates huge complex burrow systems (6) in deep sandy soil (5). Burrows occur in groups used by four to five wombats, urine and dung are used to mark burrows that are in use, and obvious paths connect adjacent burrows (5). About half of the adult females swap their burrow group during their life (5). Mating occurs in spring and summer, and most births occur from November to March (6). Females produce a single young each year and can potentially produce two young in three years when rainfall is good, but this rarely happens. The young are carried in a posterior-facing pouch for about eight to nine months (6). Although active at night, they occasionally bask in the sun in winter near the entrance of the burrow (5) (6). A number of adaptations help this species to minimise the time spent in the open; it has one of the lowest water requirements of any mammal, and very low energy expenditure (5). Despite their somewhat lumbering appearance, northern hairy-nosed wombats are capable of running at 40 kilometres per hour when threatened (8).