[6] The western pygmy possum is unusual in Cercartetus, as, unlike its grey relatives, the fur over most of its body is a bright cinnamon colour.

[8] Although there had been previously thought to be two subspecies, separated in distribution by the Nullarbor Plain, genetic studies have not revealed any significant difference between the eastern and western populations.

At night, they travel in search of food or mates, typically moving around 50 m (160 ft) each day, and they may migrate to different areas over the course of a year, depending on local plant resources.

[7] Native predators include quolls, snakes, and owls, although in modern times, the animal also falls prey to introduced carnivores such as red foxes and domestic cats.

[8] Western pygmy possums have the ability to enter torpor during inclement or cold weather, enabling them to conserve energy and food reserves.

During bouts of torpor, which may last for up to seven days at a time, body temperature falls to within one degree Celsius of ambient, and oxygen consumption to just 1% of normal.

[13] Unusually, however, the mother may give birth just two days after weaning a previous litter, with her teats dramatically changing in size to accommodate the smaller young, and the mammary glands reverting to production of colostrum.

However, several Australian states (New South Wales and South Australia) and individual parks and conservation regions have nationally listed it as Vulnerable, Endangered or Critically Endangered due to the pressure from vegetation clearing, the reduction of food sources (overgrazing of livestock), fire regimes, and introduced predators such as the red fox and feral cats.