Petropseudes dahli mothers may actually allow her young to move from branch to branch by using her body as a bridge. This has never been seen in another possum. This species also exhibits the uncommon habit of embracing their young, which is only seen in apes. They are also the only marsupial ever seen utilizing termite mounds.
Rock ringtail possums use chemical signals to communicate most extensively. Adult possums have an important scent gland on the chest region and males have a 2 cm diameter paracloacal gland. They maintain scent posts that are visited commonly. These scent posts develop a thick, lacquer-like coating. Rock ringtail possums use both urine and feces to mark these areas. These possums are also thought to mark tree branches using their paracloacal gland. Rock ringtail possums have been observed striking their tails against rocks, possibly as a form of communication. The species also is able to make grunts and growls that serve as auditory communication.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: scent marks
Perception Channels: visual ; tactile ; acoustic ; chemical
Petropseudes dahli is listed as priority species in Western Australia.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Petropseudes dahli has likely been affected by human induced habitat fragmentation and its numbers have decreased significantly. The species is listed as a priority species in western Australia and management efforts may affect forestry management and development practice.
Aboriginal peoples of the area used to capture this species. They utilized the animal both for its fur and as a food source. Rock ringtail possums are also important in education and research.
Positive Impacts: food ; body parts are source of valuable material; research and education
Rock ringtail possums may disperse seeds through their fruit eating habits. They may also influence termite populations and act as prey for regional predators.
Ecosystem Impact: disperses seeds
Rock ringtail possums feed in trees, they commonly feed within 100 meters of their rocky outcrop homes. This species eats leaves, fruit, blossoms, flowers, and occasionally feed on termites. THe blossoms of Darwin woollybutt, Eucalyptus miniata, and Darwin stringybark are all eaten by rock ringtail possums. Fruit is eaten from the following species: Zyziphus oenoplia, Vitex glabrata, Terminalia fernandiana, and Owenia vernicosa. Leaves eaten include: Flagelleria indica, Pouteria sericea, and vine reedcane.
Animal Foods: insects
Plant Foods: leaves; fruit; flowers
Primary Diet: herbivore (Folivore , Frugivore )
Rock ringtail possums are found in rocky terrain, usually sandstone outcroppings, in a small portion of northern Australia. The species has a wide distribution in northern Australia. Most commonly the species is found in the Northern Territory, Kimberley, Katherine, and Queensland.
Biogeographic Regions: australian (Native )
Rock ringtail possums live in rocky, sandstone outcrops where they are sheltered during the day. At night they move out of their sheltered rock crevices to feed in the trees within the area, often traveling no further than 10 meters from their dens. These rocky areas usually are surrounded by flatter, lowland areas. The rocky encampments have increased water holding potential and are sometimes flooded in areas.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: scrub forest
There is no information on longevity of rock ringtail possums. A closely related species, Leadbeater's possums (Gymnobelideus leadbeateri), live more than 10 years in captivity. In the wild this same species has a maximum longevity of 5 years.
Rock ringtail possums are small, stocky possums, similar in size to a small rabbit. The pelage is grey to reddish-grey on the back and a lighter, cream color on the underside. There is a dark stripe down the middle of their backs. The coat is long and thick. The tail is unique in that it is furred only half-way down, it lacks scales on the unfurred portion of the tail, unlike some of their close relatives. Rock ringtail possums have small, rounded ears. They have white hair in patches both above and below the eyes and underneath the ears. Rock ringtail possums live in rocky areas and have developed many adaptations to a more terrestrial lifestyle than many of their relatives. They have shorter legs, claws, and tails. As in other possums, the tail is prehensile.
Range mass: 1280 to 2000 g.
Range length: 334 to 383 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: female larger
In order to avoid predations, rock ringtail possums spend a large amount of time participating in sentinel behavior. They will perch on branches or ledges and scan the area for danger. Rock ringtail possums will flee from predators to their more familiar rocky habitats where they will hide in rock crevices. When confronted they may make a low growl. Rock ringtail possums also beat their tails vigorously against tree branches, causing the entire tree to shake in order to attempt to deter predators and to warn others. Potential predators of rock ringtail possums include dingos, owls, quolls, feral cats and dogs, olive pythons, Oenpelli rock pythons, and humans.
Known Predators:
Petropseudes dahli is one of few obligate monogamous marsupial species. Females live in their home range with one male. Scent posts are used commonly by the species to define home range and to mark territories. Family groups are tightly knit and consist of the mother, father, and one or occasionally two offspring. Young help with raising their younger siblings.
Mating System: monogamous ; cooperative breeder
There does not appear to be a restricted breeding season. There is normally one offspring, with occasionally two. No gestation period information is available for the species but close relatives have gestation periods from 16 to 30 days. Females have a large pouch with two teats where the new offspring spends its first five weeks. The current year's offspring are often found on the back of their parent's or nearby after leaving the safety of their mothers pouch. Previous offspring will commonly stay with the family unit to assist in rearing the next offspring.
Breeding interval: Rock ringtail possums breed twice yearly.
Breeding season: There does not appear to be a well defined breeding season. Offspring have been seen from March to September.
Range number of offspring: 1 to 2.
Average weaning age: 5 weeks.
Average time to independence: 7 months.
Average age at sexual or reproductive maturity (female): 7 months.
Average age at sexual or reproductive maturity (male): 7 months.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
There is an extensive amount of parental care in this species. Rock ringtail possums live in tight knit family groups. Care of young is undertaken by both parents and young of the previous breeding effort. Care of young is divided nearly equally between the two parents after weaning. Prior to weaning the offspring spends its time in its mothers pouch receiving nourishment from her milk. After exiting the pouch, both parents spend time grooming, resting with, and greeting their young. Mother and father both also practice several protective behaviors. Both parents spend time watching for predators, beating their tails, vocalizing, and keeping young relatively close. Females nursing young in their pouches can become defensive, on occassion even towards their mate. This behavior ranges from swinging of limbs towards counterpart or making growls or grunts. Mothers may also show some slight aggression towards subadults if they interfere with her activities or young.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Protecting: Male, Female); post-independence association with parents; extended period of juvenile learning
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 and Northern Territory and just passing the Queensland border. It is also found on Groote Eylandt.[3] It is the only species in the genus Petropseudes, but is part of the group including the common ringtail possum (Pseudocheirus peregrinus).[1]
The rock-haunting ringtail possum has one of the shortest tails of all ringtail possums, and at its end it is hairless and scaly. It lives in small groups and is mainly herbivorous. It has a stocky build and is mostly grey in colour.[3]
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.[4] A mid-dorsal stripe runs from the crown of the head to the middle of the back. Like other possums, it has a prehensile 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.[5]
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.[6]
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 its 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.[5]
The rock-haunting ringtail possum eats fruits, flowers and leaves of a variety of trees found near its habitat and occasionally feeds on termites. 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), and Owenia vernicosa. Leaves eaten include Flagelleria indica, Pouteria sericea and Vine Reedcane.[5]
Some known predators of the rock-haunting ringtail possum are the Dingo (Canis lupus dingo), the Oenpelli Python (Morelia oenpelliensis), the Olive Python (Liasis olivaceous), quolls (Dasyurus spp.), owls (Strigiformes), feral cats (Felis catus), red foxes (Vulpes vulpes), domestic dogs (Canis lupus familiaris) and humans (Homo sapiens).[4] 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.[7]
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.[5] 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.[7] 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, moving into the trees only to feed. This distinguishes it from its close, mostly arboreal relatives.[6] Its eye-shine is very bright in a spotlight but unlike most possums, it doesn't freeze when caught in a beam of light. Instead, it retreats to its rock shelter or crevices where it hides with its head in the crevice but its body exposed.[5]
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.[5] 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.[7]
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.[5] 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.[7]
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.[8] 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.[7]
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.[7] 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.[9] Embracing is a way for the adults to know the stage of maturation of the offspring.[10] A third feature of obligate monogamy shown by the Rock-haunting Ringtail Possum is the rearing of younger siblings by juveniles.[7]
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.[5] 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.[7] The species also is able to make quiet screeches and grunts that serve as auditory communication.[5]
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.[11] Another name for this species in Bininj Kunwok is djorrkkun.[12][13]
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 and Northern Territory and just passing the Queensland border. It is also found on Groote Eylandt. It is 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 possums, and at its end it is hairless and scaly. It lives in small groups and is mainly herbivorous. It has a stocky build and is mostly grey in colour.
