The scaly-tailed possum or Wyulda is one of the least known animals in Australia.
This mysterious animal was presented as a new species to the Royal Society of Western Australia as recently as 1918 by an English biologist, Wilfred Backhouse Alexander.
We look at some scaly-tailed possum facts and give you the ultimate guide to this curious creature looking at its appearance, distribution and habitat.
We will also examine its behavior and how it is being conserved.
The scaly-tailed possum is a small to medium sized marsupial. Its distinguishing feature is, unsurprisingly, its tail.
Four fifths of the tail is covered in rough scales with the remaining part near the base being covered in a dense patch of fur.
The possum’s fur is light gray with some brown flecks which becomes a reddish brown color as it reaches the base of the tail and the rump.
On the underside of the body the fur is a creamy white color.
There is an indistinct black midline which extends down the center of their head from between the eyes and continues down the back.
It has small ears and a short muzzle. The head is overall a flattened shape and the body is quite stocky.
An approximate size of the scaly-tailed possum’s head and body is 375-415 millimeters.
Males are at the larger end of the spectrum with an average length of 415 millimeters. The females are slightly smaller with an average length of 375 millimeters.
The prehensile tail of both genders is around 290-300 millimeters and is very strong with rasp-like scales along most of its length.
This kind of tail is unique to the scaly-tailed possum, hence its given name.
The weight of this marsupial ranges between 1.3 kg and 2.0 kg. Nevertheless the scaly-tailed possum can support its weight on its strong tail.
This is a slow growing species. Measurements of the skulls of juveniles reveal that they only increase by 0.26 millimeters per day.
When a female reaches sexual maturity at the age of two, its weight is only 1.1 kg, less than the lower range of the fully mature individual.
There is no evidence that there is a significant difference in size and weight between the two genders.
The scaly-tailed possum has been associated with the family of nocturnal marsupials called Phalangeridae and related to the cucuses Phalanger, also the brush-tailed possum Trichosurus.
However, there are differences in appearance between the scaly-tailed possum and the brush-tailed possum with the latter having a more fox like appearance.
The difference in tails is descriptively obvious but the brush-tailed possum is the larger of the two.
The rock ring-tailed possum Petropseudes dahli is found in a similar habitat to the scaly-tailed possum as both prefer the rocky escarpments.
This specimen has a tail which is half covered in scales but has a steep forehead, pointed muzzle and white patches near its ears.
In terms of distribution the scaly-tailed possum is found only in the Kimberley.
In the coastal regions of the northern Kimberley where there is higher rainfall the scaly-tailed possum is found between Kalumburu and Yampi Sound.
There is a smaller population further inland at Emma Gorge in east Kimberley.
The most widely acknowledged presence of the scaly-tailed possum is in the Artesian Range where it is more commonly found.
There are also populations on Boongaree Island and Bigge Island.
Most instances of scaly-tailed possums are reported in the north-west of the Kimberley, although their ideal location is in eastern Kimberley at Violet Valley.
The specimen that was presented to the Royal Society of Western Australia in 1918 was the only one reported to have been found in east Kimberley until 2012 when they were discovered in the Cockburn Range at Emma Gorge.
It is still not clear if the eastern and north-western populations of scaly-tailed possums are geographically isolated as there has not been a large scale survey of the region done.
Genetic testing on the different populations in east and north-west Kimberley showed that there was little difference between them.
There are scaly-tailed possums present in the Charnley River–Artesian Range Wildlife Sanctuary in the Kimberley region. This is a protected area of about 3000 square kilometers.
While foraging the scaly-tailed possum prefers thick, dense thickets of vines as shelter and protection from predators.
They prefer this more protective environment rather than the open woodlands and closed mangrove preferred by the brush-tailed possum.
These kinds of habitat preferred by the scaly-tailed possum are found in sandstone-based woodlands.
Here this marsupial can feed in the trees and shelter in the fissures and rock piles.
Although there are restrictions that come with this type of habitat, for the scaly-tailed possum it does provide more opportunities for dens and protection against forest fires.
This possum has disappeared in some locations and this is potentially due to the higher frequency of forest fires, as well as feral cat predation.
Studies using spatial models of the areas that the scaly-tailed possum currently inhabit show where similar suitable environments occurred in the past.
From these studies it was demonstrated that these habitats have shifted dramatically across Kimberley over the last 40,000 years.
The models also showed that the two different populations adapted to different local environments.
Looking at past populations that may have existed between the east and north-west groups of scaly-tailed possums indicates that these groups are now extinct.
Alternatively, they may still be out in river gorges and or other similar moist habitats waiting to be discovered.
Given the scaly-tailed possums’ shy and elusive nature as well as the rocky environment it prefers, this scenario is not unlikely.
Behavior & Diet
The scaly-tailed possum is shy and typically operates alone, only coming out at night to forage for food in trees and among the rocks.
They are extremely agile and nimble climbers and hold themselves by their strong prehensile tail as they reach for leaves in the trees.
Their diet includes roots, leaves, shoots, as well as the flowering parts of many plants.
As an omnivore the scaly-tailed possum will also consume insects and nuts. One study found that almost three quarters of the diet of this marsupial is composed of fruit.
As there is little information about the impact of scaly-tailed possums on their surroundings it is hard to assess at this point.
While some comparisons can be drawn between them and similar possums, the fact that they have a preference for rocky escarpments rather than open woodland makes proper assessment difficult.
Breeding usually takes place in the more favorable dry season in north western Australia between March and August.
The young are born and then make their way through the mother’s fur to the pouch.
Here they attach themselves to a teat and continue growing and developing in the safety and warmth of the mother possum’s pouch.
The offspring will remain there for between 150-200 days and will then emerge.
However, they are not fully independent of their parents for another 8 months. Typically a female will only give birth to one offspring at a time.
Females reach reproductive maturity at two years of age and the males reach sexual maturity at eighteen months.
Not much is known about how much each parent invests in the offspring.
Comparing it to the rock ring-tailed possum it could be assumed that each parent participates in the raising of the young. Although the initial burden obviously falls to the female.
As these are very secretive creatures, very little is known about their reproductive or breeding behavior.
Due to their similarity to the rock ring-tailed possum and the brush-tailed possum much of the information about them is derived from these specimens.
These other possum family groups may have matriarchal hierarchies such as with the brush-tailed possum. Dominant males and females are also more likely to mate with each other with pairs spending up to 40 days courting before mating takes place.
In brush-tailed possums scent marking and vocalization are used to avoid confrontation and direct aggression between two dominant individuals and the same may be true with scaly-tailed possums.
The International Union for Conservation of Nature (IUCN) lists the scaly-tailed possum as being ‘data deficient’.
There is a deficit of information about this animal, so it is difficult to ascertain their true conservation status.
However, the IUCN has noted that the population figures that are available show a decline in numbers.
More information is needed however before they can be classified as a threatened species.
The scaly-tailed possum is a secretive and shy animal and as such there is still a lot we don’t know about them.
Some studies have been done in the Charnley River–Artesian Range Wildlife Sanctuary and these have yielded important information about these marsupials.
However, a lot more research is needed to fully understand them, their habitats, behavior, and group hierarchy.
We hope you have enjoyed our guide to the scaly-tailed possum.