Despite their bear-like appearance, koalas are not bears. They are marsupials and belong to a completely different family.
Taxonomic Distance
Koalas and bears are both mammals, but they diverged evolutionarily long ago. Koalas are most closely related to wombats and possums.
Marsupial Traits
Like other marsupials, female koalas have pouches in which they carry and nurse their underdeveloped young.