Pseudochirulus cinereus

Geographic Range

Daintree River ringtail possums ( Pseudochirulus cinereus ) are endemic to wet tropical regions in Australasia. These animals are found in northeastern Queensland, Australia, from Thornton Peak (Daintree) to the Carbine Tableland (Queensland Department of Environment and Heritage, 1992) as well as New Guinea, Japan, and the Salawatti Islands (Nowak, 1999).

• Biogeographic Regions
• australian australian
  • native native

Habitat

Pseudochirulus cinereus is found only in tropical rainforests in Australia. They are adapted to living at higher elevations, above 300-450 m, and are found on mountaintops. Herbert River ringtail possums ( Pseudochirulus herbertensis ) are closely related to Daintree River ringtail possums. Herbert River ringtail possums spend most of their time in the canopy of the rainforest, only journeying to the ground on rare occasions. Due to their close relationship, Daintree River ringtail possums may exhibit similar behaviors.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• rainforest rainforest

Physical Description

Daintree River ringtail possums are born with dense, woolly fur (Nowak, 1999) of a light brown color, which remains the same as they become adults (unlike Herbert River ringtail possums which become much darker as adults). They have a dark stripe along the back and head. These possums can be distinguished by a pointed snout with a “roman nose” and a tapering tail. Ringtail ( Pseudochirulus ) possums in general have prehensile tails. Herbert River ringtail possums use their tails to carry small branches for nest making (Queensland Department of Environment and Heritage, 1992). Due to their arboreal lifestyle, the ventral side of the tail of Daintree River ringtail possums is hairless, ensuring a better grip as they climb. They also have hand-like feet that are well suited to life in the canopy (Andromeda Oxford Ltd., 2001).

Males tend to be larger than females. A study concerning anesthetizing Australian possums shows that Daintree River ringtail possum males weigh between 830 and 1450 g, while females range from 700 to 1200 g (Holz, 2002). Exact measurements for the length of P. cinereus were not found, but similar possums range from 167 to 368 mm head and body length (Nowak, 1999).

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

There is little information on the reproduction in Pseudochirulus cinereus . Inferences are made according to the reproduction of similar ringtail possums found in similar areas (Springer and Kirsch, 1989). Daintree river ringtail possums probably spend most of their lives alone, only meeting up with members of the opposite sex prior to breeding (Queensland Department of Environment and Heritage, 1992). They are typically polygynous animals but may shift between monogamy and polygyny depending on resource availability ("Ringtail and greater gliding possums", 2004).

• Mating System
• monogamous monogamous
• polygynous polygynous

Pseudochirulus cinereus individuals may start reproducing between 18 months and 2 years old (Springer and Kirsch, 1989). Daintree River ringtail possums may breed throughout the year, but mating peaks in April and May. The average litter size is 2 young and breeding occurs once annually. Young may spend 4 to 5 months in their mother's pouch after which they will be carried on her back (Nowak, 1999). Weaning in similar species occurs at 150 to 160 days, and young ringtail possums may become independent at 10 months ("Ringtail and greater gliding possums", 2004). Generation times for pseudocheirids is generally 2 to 4 years. Researchers believe that size may be an important factor in determining the duration of generation time. Because Pseudochirulus cinereus is smaller in size compared to other ringtail possums, they may have a shorter generation time (Springer and Kirsch, 1989).

• Key Reproductive Features
• iteroparous iteroparous
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Information regarding much of the reproduction of Pseudochirulus cinereus is unknown (Springer and Kirsch, 1989). Females carry the young in their pouches or on their backs (Nowak, 1999), and older young are sometimes left alone on a branch until their mother returns (Queensland Department of Environment and Heritage, 1992). Due to the solitary lifestyle of Daintree River ringtail possumss (Andromeda Oxford Ltd., 2001), males probably do not contribute to providing for or protecting their young.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • female

Lifespan/Longevity

The lifespan of Daintree River ringtail possums in the wild is unknown. Researchers, however, believe that Pseudochirulus cinereus may live longer than their smaller ringtail possum relatives (Springer and Kirsch, 1989). An estimation of the lifespan of P. cinereus may be 4 to 5 years in the wild ("Ringtail and greater gliding possums", 2004) and up to 15 years for captive females (Springer and Kirsch, 1989).

Behavior

Daintree River ringtail possums, like other possums, are nocturnal. Because of their primary diet of leaves, they are probably very slow moving animals, conserving energy as much as possible. A close relative, Herbert River ringtail possums ( Pseudochirulus herbertensis ) exhibit behaviors that are very slow or energetic (e.g. traveling short distances to den sites or sleeping where they feed if a den is not nearby). Daintree River ringtail possums may be similar. Because of their arboreal lifestyle and adaptations, Daintree River ringtail possums are not expected to move along the ground much or be found in isolated trees (Laurance, 1990). They are mostly solitary possums, but may on rare occasions share a den with one other possum (Andromeda Oxford Ltd., 2001). During the daytime Daintree River ringtails may create nests or take shelter in hollow trees (Nowak, 1999). Due to their solitary nature, Daintree River ringtail possums may practice "active avoidance"; there is no evidence supporting territorial defense in solitary ringtail possums ("Ringtail and greater gliding possums", 2004).

• Key Behaviors
• arboreal arboreal
• scansorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary

Home Range

The territory size of Pseudochirulus cinereus is unknown, however, it is expected that they feed within areas of 3 ha (Andromeda Oxford Ltd., 2001). Herbert River ringtail possums need an area of rainforest greater than 20 hectares in order to survive. The necessary size for Daintree River ringtail possums may be similar (Queensland Department of Environment and Heritage 1992), and they likely also need large tracts of continuous rainforest to survive (Laurance, 1990).

Communication and Perception

Like other ringtail possums, Daintree River ringtail possums are quiet animals. Young ringtail possums, however, may produce a quiet noise when they find themselves separated from their mothers (Queensland Department of Environment and Heritage, 1992). Daintree River ringtail possums may leave feces as a means of chemical communication. They may also leave their scent by rubbing objects with a gland on their sternum ("Ringtail and greater gliding possums", 2004).

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Based on the feeding habits of similar possums, it is reasonable to believe that Daintree River ringtail possums are primarily folivorous. Ringtail possums , including Pseudochirulus cinereus , contain a large caecum with bacteria in order to digest the leaves. Daintree River ringtail possums and other species of ringtail possums may occasionally eat flowers or fruits (Queensland Department of Environment and Heritage, 1992) and exhibit coprophagy (Andromeda Oxford Ltd., 2001).

• Primary Diet
• herbivore herbivore
  • folivore folivore

• Plant Foods
• leaves
• fruit
• flowers

• Other Foods
• dung

Predation

Predators of Pseudochirulus cinereus include wedge-tailed eagles ( Aquila audax ) in northern Queensland and dingoes ( Canis lupus dingo ) in northern Australia. Other predators may include owls and pythons.

Ecosystem Roles

Specific parasites of Pseudochirulus cinereus are unknown, however some possible endoparasites may include those in the Phyla Cestoda , Nematoda , and Protozoa (McKay, 1987).

Economic Importance for Humans: Positive

Daintree River ringtail possums are important members of the ecosystems in which they live. The Etolo people of Papua New Guinea will use the possums as food if they capture one during a hunt (Dwyer, 1982).

• Positive Impacts
• food food

Economic Importance for Humans: Negative

Daintree River ringtail possums generally do not live near humans and do not have adverse effects on human economies.

Conservation Status

According to the IUCN Red List, Pseudochirulus cinereus is a low risk, near threatened species (Australasian Marsupial & Monotreme Specialist Group, 1996).

Other Comments

Pseudochirulus cinereus is very similar to the Herbert River ringtail possums ( Pseudochirulus herbertensis ). Due to lack of information on P. cinereus , inferences about these animals were made according to information on Herbert River ringtail possums (Queensland Department of Environment and Heritage, 1992). Daintree River ringtail possums and Herbert River ringtail possums ( Pseudochirulus herbertensis ) have been treated as the same species previously (Australasian Marsupial & Monotreme Specialist Group, 1996). These possum species differ in color and geographic location; P. cinereus is found north of Herbert River ringtail possum habitat. The two species were separated in 1989 on the premise that they contain different numbers of chromosomes and, therefore, cannot interbreed (Queensland Department of Environment and Heritage, 1992).

According to Wilson and Reeder (2005), the species name for Daintree River ringtail possums has been changed from Pseudocheirus canescens to Pseudochirulus cinereus by Flannery in 1994.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Rachel Tooker (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor, instructor), University of Wisconsin-Stevens Point.

References

Australasian Marsupial & Monotreme Specialist Group, 2006. "IUCN" (On-line). Accessed November 02, 2006 at www.iucnredlist.org .

Burnett, S., J. Winter, R. Russel. 1996. Successful foraging by the wedge-tailed eagle (Aquila audax) in tropical rainforest in north Queensland. EMU: Austral Ornithology , 96: 277-280. Accessed October 20, 2006 at http://www.publish.csiro.au/?act=view_file&file_id=MU9960277.pdf .

Dwyer, P. 1982. Prey switching: A case study from New Guinea. The Journal of Animal Ecology , 51(2): 529-542. Accessed November 27, 2006 at http://links.jstor.org/sici?sici=0021-8790%28198206%2951%3A2%3C529%3APSACSF%3E2.0.CO%3B2-A .

Holz, P. 2002.

Restraint and Anesthesia of Possums (Diprotodontia: Burramyidae, Pseudocheiridae, Petauridae, Tarsipedidae, Acrobatidae)

Laurance, W. 1990. Comparative responses of five arboreal marsupials to tropical forest fragmentation. Journal of Mammalogy , 71(4): 641-653. Accessed November 20, 2006 at http://links.jstor.org/sici?sici=0022-2372%28199011%2971%3A4%3C641%3ACROFAM%3E2.0.CO%3B2-Z .

McKay, G. 1987. "Fauna of Australia" (On-line). Family Petauridae. Accessed November 30, 2006 at http://www.deh.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume1b/28-ind.pdf .

Nowak, R. 1999. New Guinean and Queensland Ringtailed Possums. Pp. 132-133 in Walker's Mammals of the World , Vol. 1, 6 Edition. Baltimore: Johns Hopkins University Press.

Queensland Department of Environment and Heritage, 1992. Rainforest possums. Tropical Topics: an interpretive newsletter for the tourism industry , 1(7): 1-8. Accessed November 02, 2006 at https://www.epa.qld.gov.au/register/p00820as.pdf .

Springer, M., J. Kirsch. 1989. Rates of Single-Copy DNA Evolution in Phalangeriform Marsupials. Molecular Biology & Evolution , 6(4): 331-341. Accessed October 20, 2006 at http://mbe.oxfordjournals.org/cgi/reprint/6/4/331.pdf .

Vernes, K., A. Dennis, J. Winter. 2001. Mammalian diet and broad hunting strategy of the dingo (Canis familiaris dingo) in the wet tropical rain forests of northeastern Australia. Biotropica , 33(2): 339-345. Accessed October 20, 2006 at http://www.bioone.org/archive/0006-3606/33/2/pdf/i0006-3606-33-2-339.pdf .

Wilson, D., S. Ruff. 2005. Mammal Species of the World: A Taxonomic and Geographic Reference, volume 1, edition 3 . Baltimore: Johns Hopkins University Press.

2005. Pseudochirulus cinereus. Pp. 51 in Mammal Species of the World: A Taxonomic and Geographic Reference , Vol. 1, 3 Edition. Baltimore: Johns Hopkins University Press.

2004. Ringtail and greater gliding possums. Pp. 114-117 in Grzimek's Animal Life Encyclopedia , Vol. 13, 2 Edition. Farmington Hills: Gale.

Andromeda Oxford Ltd. 2001. Ringtails, Pygmy Possums, and Gliders. Pp. 834-837 in The Encyclopedia of Mammals , Vol. 1, 1 Edition. New York: Barnes & Noble Books.