Least Concern (LC) is an IUCN category assigned to extant species or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or (prior to 2001) Conservation Dependent.
Species cannot be assigned the Least Concern category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution and/or population status.
Since 2001 the category has had the abbreviation "LC", following the IUCN 2001 Categories & Criteria (version 3.1). However, around 20% of Least Concern taxa (3261 of 15636) in the IUCN database use the code "LR/lc", which indicates they have not been re-evaluated since 2000. Prior to 2001 "least concern" was a subcategory of the "Lower Risk" category and assigned the code "LR/lc" or (lc).
While "Least Concern" is not considered a red listed category by the IUCN, the 2006 Red List still assigns the category to 15636 taxa. The number of animal species listed in this category totals 14033 (which includes several undescribed species such as a frog from the genus Philautus). There are also 101 animal subspecies listed and 1500 plant taxa (1410 species, 55 subspecies, and 35 varieties). There are also two animal subpopulations listed: the Australasian and Southern African subpopulations of Spiny Dogfish. No fungi or protista have the classification, though only four species in those kingdoms have been evaluated by the IUCN. Humans qualify for this category, and in 2008 were formally assessed as such by the IUCN.
The koala (Phascolarctos cinereus) is an arboreal herbivorous marsupial native to Australia, and the only extant representative of the family Phascolarctidae. It is classified in the suborder Vombatiformes within the order Diprotodontia, and its closest living relatives are the wombats. The koala is found in coastal areas of the continent's eastern and southern regions, inhabiting Queensland, New South Wales, Victoria and South Australia. It is easily recognisable by its stout, tailless body, round, fluffy ears and large, spoon-shaped nose. It is popularly known as the koala bear because of its bear-like appearance. The koala has a body length of 60–85 cm (24–33 in) and weighs 4–15 kg (9–33 lb). Pelage colour ranges from silver grey to chocolate brown. Koalas from the northern populations are typically smaller and lighter in colour than their counterparts in the more southern populations. It is possible that these variations are separate subspecies, but this is disputed.
Koalas typically inhabit open Eucalyptus woodlands, and the leaves of these trees make up most of their diet. Because this eucalypt diet provides them with only low nutrition and energy, koalas are largely sedentary and sleep for up to 20 hours a day. They are asocial animals, and bonding only exists between mothers and dependent offspring. Adult males communicate with loud bellows that intimidate rivals and may also attract mates. Males mark their presence with secretions from their chest glands. Being marsupials, koalas give birth to underdeveloped young that crawl into their mothers' pouches, where they stay for the first six to seven months of their life. These young koalas are known as joeys, and are fully weaned at around a year.