Pseudochirulus herbertensis

Geographic Range

Pseudocheirus herbertensis is found in Australia, in the rainforests of north-eastern Queensland between the Mount Lee area, west of Ingram, and Lamb.

• Biogeographic Regions
• australian australian
  • native native

Habitat

Herbert River ringtail possums are found mainly in dense rainforests. They are also occasionally found in tall open forests of flooded gum ( Eucalyptus grandis ) that border the western edge of the rainforests. They are almost exclusively arboreal, rarely descending to the ground. They live mainly at elevations around 350 meters.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• rainforest rainforest

Physical Description

Herbert River ringtails are easily recognized by their black body with white markings on the chest, belly, and upper forearms. Males typically have white surrounding their scrota. While adult ringtails have dark blackish pelage, juveniles are a pale fawn color with longitudinal stripes on their head and upper back. Other differentiating physical features include a pointed "Roman nose" accompanied by pinkish-orange eye shine. Head and body length ranges from 301 mm (in the smallest of females) to 400 mm (in the largest of males). Their prehensile tails range in length from 290-470 mm and taper to a pointed end. Weight ranges from 800-1230 g in females and 810-1530 g in males.

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

• Sexual Dimorphism
• male larger

Reproduction

This species is probably polygynandrous, but no information on breeding system was found.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Herbert River ringtails typically breed in early winter and again in the summer. While gestation period is not known, it averages 13 days in many other possum species. Few females carry pouch young into November. The majority of litters range between one and three young, with an average litter size of two. Female ringtails replace deceased young immediately; they can produce two separate litters in the same mating season.

After leaving their mother’s pouch, baby ringtails still feed on milk until as late as February. Although the specific maturation time of Pseudocheirus herbertensis is unknown, for the genera Pseudochirulus , young leave their mother's pouch after 10 weeks. After 10 weeks old, mother possums leave their young in nests while they eat and rest. At 3 to 4 months old, young possums are fully independent and eating adult foods.

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

Female possums carry their young inside of their pouches for approximately 10 weeks before they are ready to emerge into the world. During this period, the mother provides her babies with milk from teats within her pouch. At the end of the 10 week period, young possums leave their mother's pouch. They stay with the mother, benefiting from her care and milk for 3 to 4 months further.

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

Lifespan/Longevity

Herbert River ringtails live an average of 2.9 years in the wild. The maximum known lifespan for P. herbertensis is 6 years.

Behavior

Herbert River ringtails are nocturnal, emerging from their dens shortly after sunset and returning 50-100 minutes before daybreak. Activity usually begins with about an hour of grooming, followed by several hours of feeding. It is during these hours that a male accompanies prospective mates, with whom he may nest during daylight hours. Males are usually solitary outside of the mating period. Herbert River ringtails build their nests mainly out of stripped tree bark. Ringtail nests serve as the resting location for the animals during the daylight hours. Typical combinations of nest inhabitants include either an adult male and female, a female's litter of young, or sometimes a pair of females accompanied by their juvenile offspring. Very rarely does a nest house more than one adult male at a given time. Ringtails do not typically remain in the same nest throughout their lives and generally relocate seasonally. Upon relocation, a ringtail either builds an entirely new nest or simply inhabits an abandoned nest left by a previous inhabitant. Abandoned nests are the most likely location for a female ringtail to deposit her litter so that she can rest.

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

Home Range

Home ranges range from 0.5 to 1 hectare of rainforest canopy.

Communication and Perception

As an adaptation to being nocturnal, Pseudocheirus herbertensis relies heavily on well developed hearing. Close relatives of Herbert River ringtails have such well-developed hearing that they can easily sense the sound of a light switch clicking or mealworms crawling. Very little is known about inter-individual communication in this species, but chemical cues are a likely means of communicating reproductive state, as in most mammals.

• Communication Channels
• acoustic acoustic
• chemical chemical

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

Food Habits

Herbert River ringtails eat primarily diet leaves that are high in protein content. Specifically, they eat the leaves of pink ash ( Alphitonia petriei ). Other secondary food sources include brown quandong ( Elaeocarpus ruminatus ), white basswood ( Polyscias murrayi ), bumpy satinash ( Syzygium cormiflorum ), paper-barked satinash ( Syzygium alliiligneum ), red eungella satinash ( Acmena resa ), pink bloodwood ( Eucalyptus acmenoides ), cadaghi ( Eucalyptus torelliana ), and a vine ( Melodinus bacellianus . Ringtails have selenodont teeth which allow them to efficiently grind leaves, promoting bacterial fermentation in the gut. Herbert River rintails have a large caecum and colon specialized for housing the symbiotic bacteria involved in fermentation. Foliage remains in a ringtail's system for a long time relative to that of other animals. Upon completion of fermentation, the contents of the caecum are expelled and then reingested. The nutrient content of this "first cycle" feces is quickly absorbed by the animal's intestine.

• Primary Diet
• herbivore herbivore
  • folivore folivore
• coprophage coprophage

• Plant Foods
• leaves

• Other Foods
• dung

Predation

One of the only known predation threats to P. herbertensis are carpet snakes ( Morelia carinatus ) It is reasonable to assume that P. herbertensis is prey to the known predators of its close relative, Pseudocheirus peregrinus . These include powerful owls ( Ninox strema ) and rufous owls ( Ninox rufa ).

Ecosystem Roles

Pseudochirulus herbertensis serves as host to up to twelve different types of parasites, the most notable of which are tapeworms and mites. Their herbivory may impact vegetation in the communities in which they live.

Economic Importance for Humans: Positive

Herbert River ringtails are important members of the ecosystems in which they live. They may help to attract ecotourism to Australian rainforests they inhabit.

• Positive Impacts
• ecotourism ecotourism

Economic Importance for Humans: Negative

There are no known negative impacts of P. herbertensis .

Conservation Status

Herbert River ringtail populations currently seem secure. Their dependence on primary rainforest, however, makes them vulnerable to habitat destruction.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Alison Berger (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.

References

Flannery, T. 1994. Possums of the World . Chastwood, Australia: GED Productions.

Gewalt, W. 1967. Opossums. Pp. 57-69 in Grzimek's Animal Life Encyclopedia , Vol. Mammal I, 1st Edition. New York: Van Nostrand Reinhold Company.

McKay, G. 1987. "Fauna of Australia" (On-line). Family Petauridae. Accessed March 12, 2006 at http://www.deh.gov.au/biodiversity/abrs/publications/fauna-of-australia/pubs/volume1b/28-ind.pdf .

Strahan, R. 1983. Complete Book of Australian Mammals . Australia: Argus and Robertson.

Thomson, J., W. Owen. 1964. A field study of the Australian Ringtail Possum Pseucocheirus peregrinus (Marsupialia: Phalangeridae). Ecological Monographs , 34 (1): 27-52. Accessed April 23, 2006 at http://links.jstor.org/sici?sici=0012-9615(196424)34%3A1%3C27%3AAFSOTA%3E2.0.CO%3B2-N .

Winter, J., N. Goudberg. 1995. Mammals of Australia . United States of America: Smithsonian Institution Press.

Wet Tropics Management Authority. 2002. "Google Scholar" (On-line). Wet Tropics Plants and Animals. Accessed February 09, 2006 at http://www.wettropics.gov.au/pa/pa_possums.html .