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Pseudochirulus herbertensisHerbert River ringtail

By Alison Berger

Geographic Range

Pseudochirulus herbertensis is found in Australia, in the rainforests of north-eastern Queensland between the Mount Lee area, west of Ingram, and Lamb. (Winter and Goudberg, 1995)

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. (Winter and Goudberg, 1995)

  • Average elevation
    350 m
    1148.29 ft

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. (Winter and Goudberg, 1995)

  • Sexual Dimorphism
  • male larger
  • Range mass
    800 to 1530 g
    28.19 to 53.92 oz
  • Range length
    636 to 870 mm
    25.04 to 34.25 in

Reproduction

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

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 Pseudochirulus 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. (Gewalt, 1967; Thomson and Owen, 1964)

  • Breeding interval
    Herbert River ringtails breed twice each year.
  • Breeding season
    There is a major breeding season in early winter and a shorter, second breeding season in summer
  • Range number of offspring
    1 to 3
  • Average gestation period
    13 days
  • Range weaning age
    3 to 4 months
  • Range time to independence
    3 to 4 months
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

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. (Gewalt, 1967)

  • Parental Investment
  • 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. (McKay, 1987; McKay, 1987)

  • Range lifespan
    Status: wild
    6 (high) years
  • Average lifespan
    Status: wild
    5 years
  • Average lifespan
    Status: wild
    2.9 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. (Thomson and Owen, 1964; Winter and Goudberg, 1995)

Home Range

Home ranges range from 0.5 to 1 hectare of rainforest canopy. (Winter and Goudberg, 1995)

Communication and Perception

As an adaptation to being nocturnal, Pseudochirulus 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. (Gewalt, 1967)

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. (McKay, 1987; Winter and Goudberg, 1995)

  • 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). (McKay, 1987; Strahan, 1983)

  • Known Predators
    • carpet snakes (Morelia carinatus)
    • powerful owls (Ninox strema)
    • 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. (Flannery, 1994)

Commensal/Parasitic Species

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.

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. (Flannery, 1994)

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.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

coprophage

an animal that mainly eats the dung of other animals

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

folivore

an animal that mainly eats leaves.

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

References

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.

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

Gewalt, W. 1967. Opossums. Pp. 57-69 in B Grzimek, ed. 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.

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