Numbats also possess a sternal scent gland, which may be used for marking their territories. Although the numbat finds termite mounds primarily using scent, it has the highest visual acuity of any marsupial, and, unusually for marsupials, has a high proportion of cone cells in the retina. These are both likely adaptations for its diurnal habits, and vision does appear to be the primary sense used to detect potential predators. Numbats are able to enter a state of torpor, which may last up to fifteen hours a day during the winter months. Numbats were formerly widely distributed across southern Australia, from Western Australia to north-western New South Wales. However, their range has significantly decreased since the arrival of Europeans, and the species has survived only in two small patches of land in the Dryandra Woodland and the Perup Nature Reserve, both in Western Australia. In recent years, however, it has been successfully reintroduced into a few fenced reserves, including some in South Australia (Yookamurra Sanctuary) and New South Wales (Scotia Sanctuary). Today, numbats are found only in areas of eucalypt forest, but they were once more widespread in other types of semiarid woodland, spinifex grassland, and in terrain dominated by sand dune. Numbats are insectivores and subsist on a diet of termites. An adult numbat requires up to 20,000 termites each day. The only marsupial fully active by day, the numbat spends most of its time searching for termites. It digs them up from loose earth with its front claws and captures them with its long, sticky tongue. Despite its banded anteater name, it apparently does not intentionally eat ants; although the remains of ants have occasionally been found in numbat excreta, these belong to species that themselves prey on termites, so were presumably eaten accidentally, along with the main food. Known predators on numbats include the carpet python "Morelia spilota imbricata", introduced red foxes, and various falcons, hawks, and eagles. Adult numbats are solitary and territorial; an individual male or female establishes a territory of up to 1.5 square km (370 acres) early in life, and defends it from others of the same sex. The animal generally remains within that territory from then on; male and female territories overlap, and in the breeding season, males will venture outside their normal home ranges to find mates.