The term “rat-kangaroo” can be misleading. It is the common name for a group of small marsupials native to Australia belonging to the family Potoroidae, which includes animals like bettongs and potoroos. They are not rodents but are related to the more familiar kangaroos and wallabies. Once widespread, these animals represent a unique branch of Australian wildlife.
Physical Characteristics and Habitat
Rat-kangaroos are generally small, about the size of a rabbit, with body lengths for most species ranging from 30 to 38 centimeters. Their powerful hind legs are adapted for hopping, though they are also capable of scurrying on all fours. They have distinctly pointed faces and, in some species like potoroos, shorter ears and tails. The different species vary in weight, with the Northern Bettong being one of the smallest at around 1.2 kg, and the Rufous Bettong being the largest at up to 2.8 kg.
A notable feature of many rat-kangaroos is their tail, which is often long and can be prehensile. They use it to grasp and carry materials, particularly for building nests. The tail may be sparsely-furred, and in some species, like the Tasmanian bettong, it has a distinctive crest of black hair and a white tip. Their fur coloration ranges from grey to ginger and brown, providing camouflage.
These marsupials inhabit a variety of environments across Australia, from dense scrublands and temperate woodlands to tall open forests with grassy understories. For instance, the musky rat-kangaroo is found in the tropical rainforests of northeastern Queensland, while other species are adapted to arid and semi-arid shrublands. They seek shelter in dense undergrowth, which provides cover from predators. The burrowing bettong is unique among the kangaroo group as it constructs and lives in burrows.
Diet and Behavior
A substantial portion of their food consists of underground fungi, a practice known as mycophagy. By digging for and consuming these fungi, they act as “ecosystem engineers,” dispersing fungal spores through their droppings. These spores are important for the health of many native trees, forming symbiotic relationships with their root systems.
Beyond fungi, their diet also includes other plant matter and some invertebrates. They forage for tubers, seeds, and grasses, and some species will also eat grubs and worms. The Rufous Bettong, for example, is known to travel up to 1.5 km from its nest to find food.
Most rat-kangaroo species are nocturnal, with an exception being the musky rat-kangaroo, which is primarily active during the day. A characteristic behavior is their method of nest construction. Using their prehensile tails, species like bettongs gather bundles of vegetation to build a concealed nest.
Conservation Status and Threats
Many rat-kangaroo populations have faced significant declines, and several species are now considered threatened or endangered. The woylie, or brush-tailed bettong, is listed as Critically Endangered, while the Northern Bettong is Endangered. Some, like the Desert Rat-kangaroo, are now extinct. This vulnerability is a result of factors intensified since European settlement.
A primary threat is habitat loss and fragmentation. Widespread clearing of land for agriculture and urban development has destroyed the dense undergrowth and woodlands these animals depend on for food and shelter. As their habitats shrink, populations become isolated and more susceptible to other pressures.
Predation by introduced species poses another major threat. Red foxes and feral cats have become highly effective predators of these small marsupials. Their small size and ground-dwelling habits make them easy targets for these invasive predators. This combination of threats has led to the precarious status of many species.