The Honey Possum has no close relatives. It is currently classified as the only member of its genus and of the family Tarsipedidae, but many authorities believe that it is sufficiently distinct to be more properly raised to a separate superfamily within the Diprotodontia, or perhaps even further.
It is one of the very few entirely nectarivoruos mammals; it has a long, pointed snout and a long, protusible tongue with a brush tip like a honeyeater or a hummingbird. It is thought to be the sole survivor of an otherwise long-extinct marsupial group. Although restricted to a fairly small range in the southwest of Western Australia, it is locally common and does not seem to be threatened with extinction so long as its habitat remains intact and diverse. (Floral diversity is particularly important for the Honey Possum as it cannot survive without a year-round supply of nectar, and unlike nectarivorous birds, it cannot easily travel long distances in search of fresh supplies.)
The Honey Possum is mainly nocturnal but will come out to feed during daylight in cooler weather. Generally, though, it spends the days asleep in a shelter of convenience: a rock cranny, a tree cavity, the hollow inside of a grass tree, or an abandoned bird nest. When food is scarce or in cold weather, it becomes torpid to conserve energy.