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Pseudochirops archerigreen ringtail possum

By Sarah Davis

Geographic Range

Presently the green ringtail possum is evenly distributed throughout northeast Queensland, Australia (Laurance 1990). This species of possum has been observed in a range extending from Paluma on into the Mount Windsor Tableland, which is located just west of Mossman. It can only be found at altitudes greater than about 300 m (Winter and Goudberg 1995).

Habitat

Pseudochirops archeri has evolved a primarily arboreal lifestyle. This species favors areas with an abundance of trees and vines in the Australian tropical rainforest. It rarely, if ever, descends to the ground. It has only been observed at ground level when a gap to a neighboring tree is too great to reach (Winter and Goudberg 1995). Even then the individual remains on the ground only for the short amount of time it takes to reach the next tree.

This species has also been observed to populate areas of secondary regrowth and in the edges of forest habitats (Laurance 1990).

Under normal conditions the green ringtail possum forages at an average height of 13.5m (Laurance 1990).
  • Range elevation
    300 (low) m
    984.25 (low) ft

Physical Description

Black, yellow, and white banding on its hairs causes the characteristic lime-green coloration of this species. The body is plump and covered with dense, soft fur with two silvery stripes that run medially down its back (Winter and Goudberg 1995). There are visible patches of white fur below its large eyes and small ears (The Living Museum). This species of possum has the characteristic strong prehensile tail of the pseudocheiridids, but it is modified to be relatively short and very thick at its base. The tails of the ringtail possum curl at the tip when it is not being used for support (Grzimek and Ganslosser 1990).

The feet of this family are syndactylous. The first and second digits are opposable to the third and forth and fifth on the forefeet, and the hindfeet have an opposable hallux (Myers 1999).

The green possum's dentition is similar to that found in koalas (Phascolarctos cinereus) in that its molar teeth have sharp crescent-shaped edges used in cutting foliage (Grzimek and Ganslosser 1990 and Vaughan et al.1965). It has molars that are diprotodont and a dental formula of 3/2, 1/0, 3/3, 4/4 = 40 (Myers 1999).

  • Range mass
    670 to 1350 g
    23.61 to 47.58 oz
  • Average mass
    1092 g
    38.48 oz
  • Range length
    285 to 377 mm
    11.22 to 14.84 in
  • Average length
    344 mm
    13.54 in

Reproduction

Most breeding occurs in the second half of the year, with peaks in reproduction occuring in June and July (Winter and Goudberg 1995 and The Living Museum). Since this species is stictly solitary it is likely that it practices polygamy. Although the female green possums have two teats in their marsupiums, the mother normally gives birth to a single offspring.

  • Breeding season
    June and July
  • Average number of offspring
    one

Typical of metatherian development, this possum gives birth to young, underdeveloped offspring. After birth the young travels to the mother's marsupium, which opens anteriorly on her ventral side. The young remains there for a few months. When the offspring matures further it climbs out of its mother's pouch and takes position on her back (Winter and Goudberg 1995). The offspring of this species of possum exhibits the longest known stage of back-riding as compared to other related species (Moeller 1990). During this stage the juvenile constantly clings to the mother's back and observes her behavior. During the next stage of development the offspring travels on its own, but will follow the mother around for several more weeks as she forages through the trees (Grzimek and Ganslosser 1990).

Lifespan/Longevity

unknown

Behavior

Unlike other possums that build nests for roosting, the green possum spends its days sleeping out in the open in a fork of a tree. As it prepares to sleep it sits on its thick tail and then rolls itself into a tight ball tucking its tail, face and forefeet into its stomach. It grasps the tree limb with its opposable hindfeet (Grzimek and Ganslosser 1990 and Winter and Goudberg 1995). It remains in this position until nightfall unless it is disrupted. If awakened the possum will swiftly run away and may forage for the remaining part of the day(Winter and Goudberg 1995).

Communication and Perception

Food Habits

The green ringtail possum is unusual in its family in that it has a primarily foliovorous diet. It usually prefers mature leaves that contain lots of fiber and little protein, and it especially likes foliage from fig trees. Many of its favorite plant species grow on the edges of the forest habitat (Laurance 1990). Normally an individual bites a leaf off from its petiole and grasps it in its forefeet during ingestion (Winter and Goudberg 1995). Although this possum primarily feeds on leaves, it has been observed to feed on ripe figs occasionally (Winter and Goudberg 1995).

The green ringtail possum is one of few species that has adapted to feeding on the leaves of the stinging tree. These trees are a member of the nettle family that have leaves covered in prickly hairs. Humans that touch these leaves may require medical attention, but somehow this possum is able to ingest them (Winter and Goudberg 1995).

This species has a small caecum and a large colon, which is characteristic of foliovores (Winter and Goudberg 1995).

Like its relative, the common ringtail, the green ringtail practices coprophagy, in which it ingests its feces for a second digestion of the material in order to extract more nutrients (Vaughan et al 1965 and Winter and Goudberg 1995).

Predation

The green tint to this animal makes it fairly well hidden when it is among the leaves of the forest and allows it to remain undetected by many predators. Also, its sleeping behavior of rolling into a condensed ball adds to its camouflage. This species of ringtail possum is much quicker than the other species at running through the canopy of the forest on trees and vines (Winter and Goudberg 1995).

Economic Importance for Humans: Positive

In the past the green possum was hunted for food by Aborigines (Winter and Goudberg 1995). However, this is no longer a common practice.

Economic Importance for Humans: Negative

No known cost

Conservation Status

Although the green ringtail possum is sparsely distributed throughout its region, it is not considered to be threatened because of its great adaptability to changing environments. Deforestation does not appear to have severe effects on this species survival because it is able to survive and thrive in secondary regrowth forests and edge habitats. Also, these animals feed heavily on fig trees, which are not logged commercially for lumber. It is able to survive because of its den-less sleeping adaptation, its increase in offspring care, and its ability and preference for feeding on tree species that are found in edge habitats (Laurance 1990). This species is not currently severely threatened by marginal habitat loss, but through further deforestation of the Australian rainforest, the green ringtail possum may see future depletion in its populations.

Other Comments

Although the green ringtail possum is sparsely distributed across its habitat, its populations are not severely threatened probably because it has evolved excellent camouflage characters and certain food preferences. The green appearance of this animal and its ball-like sleeping behavior cause the possums to nearly disappear among their leafy habitats. This discretion protects them from heavy predation. Also, this species has evolved feeding preferences for fig trees, which are eaten by very few other species and are not logged during deforestation. They are also very capable of surviving in marginal habitats. With all of these adaptations the green possum appears very well adapted to its environment.

Contributors

Sarah Davis (author), University of Michigan-Ann Arbor, Bret Weinstein (editor), University of Michigan-Ann Arbor.

Glossary

Australian

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

World Map

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.

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

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.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

herbivore

An animal that eats mainly plants or parts of plants.

internal fertilization

fertilization takes place within the female's body

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

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.

sexual

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

solitary

lives alone

tactile

uses touch to communicate

tropical

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

viviparous

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

year-round breeding

breeding takes place throughout the year

References

"The Living Museum" (On-line). Accessed Oct 2001 at www.wettropics.gov.au.

Grzimek, B., U. Ganslosser. 1990. Grzimek's Encyclopedia of Mammals Volume 1. New York, New York: McGraw-Hill.

Laurance, W. Nov 1990. Comparative Responses of five Arboreal Marsupials to Tropical Forest Fragmentation. Journal of Mammalogy, 71: 641-653.

Myers, P. Sept 1999. "Animal Diversity Web - Pseudocheiridae" (On-line). Accessed Oct 2001 at animaldiversity.ummz.umich.edu.

Vaughn, T., J. Ryan, N. Czaplewski. 1965. Mammalogy. Fort Worth, TX: Saunder's College.

Winter, J., N. Goudberg. 1995. Mammals of Australian. Chatswood, New South Wales, Australia: Reeds Books.

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