The rock-haunting ringtail possum (''Petropseudes dahli''), also known as the rock ringtail possum, is a species of
Australian
possum. It is found in rocky escarpments in the
Kimberley,
Arnhem Land and
Gulf of Carpentaria across
Western Australia
Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...
and
Northern Territory
The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an Australian territory in the central and central northern regions of Australia. The Northern Territory shares its borders with Western Aust ...
and just passing the
Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, establishe ...
border. It is also found on
Groote Eylandt
Groote Eylandt ( Anindilyakwa: ''Ayangkidarrba'' meaning "island" ) is the largest island in the Gulf of Carpentaria and the fourth largest island in Australia. It was named by the explorer Abel Tasman in 1644 and is Dutch for "Large Island" i ...
.
It the only species in the genus ''Petropseudes'', but is part of the group including the
common ringtail possum (''Pseudocheirus peregrinus'').
[
The rock-haunting ringtail possum has one of the shortest tails of all ]ringtail possum
Pseudocheiridae is a family of arboreal marsupials containing 17 extant species of ringtailed possums and close relatives. They are found in forested areas and shrublands throughout Australia and New Guinea.
Characteristics
Physically, they ap ...
s, and at its end it is hairless and scaly. It lives in small groups and is mainly herbivorous
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpar ...
. It has a stocky build and is mostly grey in colour.[
]
Description
The rock-haunting ringtail possum is almost the size of a small rabbit. It is grey to reddish-grey in colour on the back, while its underside is a light cream colour. It has white hair patches underneath its small, round ears and both above and below the eyes.[ADW: Petropseudes dahli: Information]
/ref> A mid-dorsal stripe runs from the crown of the head to the middle of the back. Like other possums, it has a prehensile
Prehensility is the quality of an appendage or organ that has adapted for grasping or holding. The word is derived from the Latin term ''prehendere'', meaning "to grasp". The ability to grasp is likely derived from a number of different orig ...
tail, adapted for grasping especially by wrapping around. However, the tail is unique in its appearance compared to that of other possums as it is covered with fur only halfway down. Males are 33.4 to 37.5 cm long while females are generally bigger and range from 34.9 to 38.3 cm in length and weigh between 1,280 and 2,000 grams. Another uncommon feature in the appearance of this species is that it has vertical pupils.
Ecology
The rock-haunting ringtail possum disperses seeds through its fruit eating habits. It also influences termite populations and acts as prey for regional predators.
The rock-haunting ringtail possum has been affected by human induced habitat fragmentation and hence, its numbers have decreased significantly. The species is listed as a priority species in Western Australia.
Habitat
The rock-haunting ringtail possum lives exclusively in rocky outcrops and prefers areas with large boulders and deeply fissured rock. It uses the crevices to hide by just sticking its head into the crevice with the body exposed. It is strictly nocturnal; it only moves out of it sheltered rock crevices to climbing trees to feed at night. It does not make a nest and has been observed occasionally to be sleeping in well protected rock ledges during the day. This suggests a high level of adaptation to a terrestrial existence. Indicators of a reduction in arboreal adaptation are shorter legs, shorter claws, shorter tail and a slightly longer snout.
Diet
The rock-haunting ringtail possum eats fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
s, flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...
s and leaves of a variety of trees found near its habitat and occasionally feeds on termite
Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blatto ...
s. It usually stays close to the rocks while feeding but has been found as far as 100m from the nearest outcrop. Most common of the blossoms it eats are of Darwin Woollybutt ('' Eucalyptus miniata'') and Darwin Stringybark ('' Eucalyptus tetrodonta''). Its major fruit intake is from '' Zyziphus oenoplia'', '' Vitex glabrata'', Billy Goat Plum (''Terminalia ferdinandiana
''Terminalia ferdinandiana'', most commonly known as the Kakadu plum and also called the gubinge, billygoat plum, green plum, salty plum, murunga, mador and other names, is a flowering plant in the family Combretaceae, native to Australia, wid ...
''), and '' Owenia vernicosa''. Leaves eaten include '' Flagelleria indica'', '' Pouteria sericea'' and Vine Reedcane.
Known predators
Some known predators of the rock-haunting ringtail possum are the Dingo (''Canis lupus dingo''), the Oenpelli Python
The Oenpelli python or Oenpelli rock python (''Simalia oenpelliensis'' or ''Nyctophilopython oenpelliensis'') is a species of large snake in the family Pythonidae. The species is endemic to the sandstone massif area of the western Arnhem Land reg ...
(''Morelia oenpelliensis''), the (''Liasis olivaceous''), quoll
Quolls (; genus ''Dasyurus'') are carnivorous marsupials native to Australia and New Guinea. They are primarily nocturnal and spend most of the day in a den. Of the six species of quoll, four are found in Australia and two in New Guinea. Anoth ...
s (''Dasyurus'' spp.), owl
Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...
s (Strigiformes), feral cats (''Felis catus''), domestic dogs
The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relative. Do ...
(''Canis lupus familiaris'') and human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, cultu ...
s (''Homo sapiens''). The rock-haunting ringtail possum spends a large amount of time participating in sentinel behaviour to avoid predators. It perches on branches or ledges and scans the area for danger. In an attempt to deter predators and to warn others, this possum beats its tail against tree branches vigorously causing the entire tree to shake.
Lifestyle
Of all the Australian possums, the rock-haunting ringtail possum lives in the most tightly knit family groups. Adults and their young will stay within 2–3 metres of each other throughout the night. The family groups are generally made up of about 4 individuals, although group sizes of 2 to 10 individuals have been reported. The possum spends most of its time sheltered within rock piles or crevices. After dark it moves from its rocky home into the nearby trees where it feeds. This possum is secretive, difficult to trap and avoids contact and confrontation as far as possible. It is primarily terrestrial
Terrestrial refers to things related to land or the planet Earth.
Terrestrial may also refer to:
* Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
, moving into the trees only to feed. This distinguishes it from its close, mostly arboreal
Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose nu ...
relatives. Its eye-shine is very bright in a spotlight but unlike most possums, it doesn't freeze when caught in a bean of light. Instead, it retreats to its rock shelter or crevices where it hides with its head in the crevice but its body exposed.
Reproduction
There appears to be no particular season for breeding. However, females with a large young in the pouch and a young on the back have been seen in March, July, August and September. Although the gestation period information is not available for the species, it is known that close relatives have gestation periods from 16 to 30 days. The new offspring spends its first five weeks in the female's large pouch which has two teats. The parents usually carry the new offspring on their back after they have left the mother's pouch. Caring for the young is divided nearly equally among the parents. The parents are assisted in raising the offspring by the previous offspring who commonly stay with the family unit. The parents practice protective behaviours such as spend time watching for predators, tail beating, and vocalizing and marshaling the young to keep them relatively close.
Home range and obligate monogamy
Both sexes have about the same home range size. Average home range is 0.9 hectares, with home ranges ranging in size from 0.5 to 1.2 hectares. The average density in these home ranges is 0.4 possums per hectare. Females live with one male in their home range, which are commonly marked by scent posts. To scent-mark, the rock-haunting ringtail possum rubs or presses their cloacal-caudal region or chest against the surface. While the possum also marked rock ledges and trees within its home ranges, scent marking was most vigorous around den sites.
The rock-haunting ringtail possum is one of few obligate monogamous marsupial species. A consistent characteristic of obligate monogamy displayed by this species is the existence of cohesive and persistent pair bonds with mutual or asymmetrical attraction between adults. Both sexes of this species maintain strong pair bonds, as shown by the wide array of maintenance behaviours, which is a measure of bond 'strength'. However, males maintained the pair bond at a higher rate than females. Both sexes shared the decision-making process in terms of changing group activity.
Presence of long-lasting bonds between parents and young seen in the family of this species is another attribute of obligate monogamy. Both sexes of the rock-haunting ringtail possum showed substantial long-term care of offspring. An unusual interaction observed between parents and young were the embrace by adult males and the bridge formation. Both sexes embrace young, whereas only females engage in bridge formation. The mother allows her young to move from branch to branch by using her body as a bridge. This has never been seen in another possum. Embracing is a way for the adults to know the stage of maturation of the offspring. A third feature of obligate monogamy shown by the Rock-haunting Ringtail Possum is the rearing of younger siblings by juveniles.
Communication
The rock-haunting ringtail possum mostly uses scent to communicate. Adult possums have a distinct gland on the chest and males have a paracloacal gland which is about 2 cm in diameter. The possum maintains scent posts that are visited commonly. The rock-haunting ringtail possum uses both urine and faeces to mark these areas. This possum is also thought to mark tree branches using its paracloacal gland. The rock-haunting ringtail possum has been observed striking its tail against rocks, possibly as a form of communication. The species also is able to make quiet screeches and grunts that serve as auditory communication.
In Aboriginal language and culture
The Kunwinjku of Western Arnhem Land hunted ngingma, as they call this possum by placing sugar bag (bush honey) on a rock. Attracted to the bait the animal was then speared. Another name for this species in Bininj Kunwok
Bininj Kunwok is an Australian Aboriginal language which includes six dialects: Kunwinjku (formerly Gunwinggu), Kuninjku, Kundjeyhmi (formerly Gundjeihmi), Manyallaluk Mayali (Mayali), Kundedjnjenghmi, and two varieties of Kune (Kune Dulerayek a ...
is djorrkkun.
References
{{Taxonbar, from=Q1404175
Possums
Mammals of Western Australia
Mammals of the Northern Territory
Mammals described in 1895