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Hemibelideus lemuroideslemuroid ringtail possum

By Jennifer Humfleet

Geographic Range

The range of lemuroid ringtail possums is restricted to the northeastern rainforests of Queensland, Australia. Hemibelideus lemuroides are found in an area of only 300,000 hectares in two rainforests in the Atherton Tablelands and Mount Carbine Tablelands areas. (Flannery, 1994)

Habitat

Lemuroid ringtail possums are strictly arboreal. Their habitat is further limited by both elevation and preference for particular tree types. Favoring the high canopies of the rainforest, they are found above 480 meters and 900 meters on the Atherton and Mount Carbine Tablelands, respectively. Furthermore, lemuroid ringtail possums are found only in mature forests, not secondary or regrowth forests. (Flannery, 1994; Laurance, 1990; Smith and Hume, 1984)

  • Range elevation
    900 (high) m
    2952.76 (high) ft
  • Average elevation
    480 m
    1574.80 ft

Physical Description

Lemuroid ringtail possums are small to medium sized animals, with a body length of 30 to 38 cm and a tail length of 30 to 35 cm. Male weights range from 810 to 1060 g, females from 750 to 1140 g. Covered in long fur, the body is uniformly colored: brownish-gray on the back, head, and shoulders, with a yellowish underbelly. A rare white form of H. lemuroides has been documented and is found in unusually high proportions on Mount Carbine. The tail is covered in the same dark fur, with only the tip being bare. The bare tip acts as a friction pad to allow H. lemuroides to climb and grab objects. The highly prehensile tail also aids in steering when these possums throw themselves from tree to tree in great leaps. Each forelimb ends in 5 freestanding digits with an extended hallux to improve grip. Sharp nails on the end of each digit are long and curved, acting like a grappling hook. On the hindlimbs, the second and third toes are fused, making H. lemuroides syndactylous. The most distinctive feature of lemuroid ringtail possums, and the feature most often used by field researchers to identify them, is the color of their eyeshine. The eyeshine, or the color the tapetum lucidum appears to reflect, is bright yellow. Lemuroid ringtail possums are the only animals in the area to have yellow eyeshine.

Adults and young can only be distinguished by comparing body size and eye markings. Young are slightly smaller, have silvery eyeshine, and their eyes are closer together. However, these features are not easy to distinguish when the animals are high up in the canopy.

Lemuroid ringtail possums are very distinctive because of their odd assortment of possum, lemur, and glider-like features. The similarities between these possums and lemurs are in facial characteristics, including short snouts, large, forward-facing eyes, and small ears. Furthermore, similar to gliders, H. lemuroides have skeletal and musculature adaptations to accommodate a leaping lifestyle. Sometimes said to represent an early morphological stage of gliding, H. lemuroides have a flap of skin along their sides that is about 25 mm wide. (Burnie and Wilson, 2005; Flannery, 1994; Holz, 2002; Jackson, 2000; Smith and Hume, 1984; Vaughan, et al., 2000; Winter, 1995)

  • Sexual Dimorphism
  • female larger
  • Range mass
    750 to 1140 g
    26.43 to 40.18 oz
  • Range length
    30.5 to 38 cm
    12.01 to 14.96 in

Reproduction

Little is known about the mating system of Hemibelideus lemuroides. Adults have a strong, long lasting pair bond. Monogamous couples raise their offspring together, forage for food together, and share a den. The exact duration of the pair bond is unknown, but it lasts well into the period when the offspring finally become autonomous, about 9 months after birth. (Flannery, 1994; Smith and Hume, 1984)

Young are born in early August and crawl into the pouch on the female's underside. The young remains in the pouch until November, drinking milk from the mother. While the mother has two teats in her pouch, only one offspring is reared at a time. After 6 to 7 weeks, the young leave the pouch and ride on the mother’s back for another 6 months, from October to April.

Information about sexual maturity is unknown, but we can look for generalizations among their close relatives. Petauroides volans reach sexual maturity after 2 years, lemuroid ringtail possumss may have a similar pattern. (Baverstock, et al., 1990; Burnie and Wilson, 2005; Flannery, 1994; Lindenmayer and Lacy, 1995; Vaughan, et al., 2000; Winter, 1995)

  • Breeding interval
    Lemuroid ringtail possumss breed once yearly.
  • Breeding season
    Mating probably occurs in mid winter (late June, July).
  • Range number of offspring
    1 (high)
  • Average number of offspring
    1
    AnAge
  • Average weaning age
    4 months
  • Average time to independence
    6 months
  • Average age at sexual or reproductive maturity (female)
    2 years
  • Average age at sexual or reproductive maturity (male)
    2 years

Parental investment after birth lasts 9 months. The offspring is carried in the mother's pouch for the first 4 months, receiving food and protection. Young Hemibelideus lemuroides are altricial, unable to provide for themselves. The young suckles milk from its mother until it leaves the pouch. Then both parents are active in caring for their young. Lemuroid ringtail possums are social, and the core unit is the adult parents and their single young. Single-family units are often seen foraging with other family groups. Outside of the family, however, there is no hierarchical social structure.

The offspring follow and learn from both parents for another 5 months before gaining independence. During this time, they rarely intentionally leave their parents' side. Both parents spend considerable amounts of time protecting and teaching the offspring. They often remain in close proximity, even when the young have reached adulthood. (Burnie and Wilson, 2005; Flannery, 1994; Smith and Hume, 1984; Winter, 1995)

  • 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
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • post-independence association with parents
  • extended period of juvenile learning

Lifespan/Longevity

Lemuroid ringtail possums have not been held in captivity, nor have any been recorded long term in the wild. Judging by close relatives monitored in the wild, an average life expectancy might be as long as 12 to 15 years. (Lindenmayer and Lacy, 1995)

Behavior

Lemuroid ringtail possums are completely nocturnal and relatively social. Foraging in trees, H. lemuroides individuals stay active until daybreak. To stay out so late is unusual in Australian rainforest possums. During the day they sleep in hollow trees. While they don’t build nests, they will den in foliage filled logs. The den often holds a single family unit. This unit most often includes an adult male, an adult female, and a single young. The family unit is the primary social unit. Mating bonds last longer in lemuroid ringtail possums than in many other social possums. During foraging, a number of family units are likely to be found together. Eight individuals have been spotted foraging in a common area, and up to 10 groups recorded per hour.

When foraging in the treetops, lemuroid ringtail possums appear most like gliders. While the small gliding membrane (plagiopatagium) isn’t enough to support a full glide, they do leap from tree to tree. They jump with limbs outstretched, flattening their body. When airborne, they use their prehensile tails as rudders. Leaping about 2 to 3 meters in a free fall, they land heavily. The resulting crash is an easy way to locate them. (Burnie and Wilson, 2005; Flannery, 1994; Jackson, 2000; Johnson-Murray, 1987; Laurance, 1990; Winter, 1995)

  • Average territory size
    3000 km^2

Communication and Perception

Communication among lemuroid ringtail possums is not well understood. When a young possum is separated from its mother, the young cry with a keening squeak. Reports differ when describing the behavior of adults. Some say that adults are silent, while others maintain that adults reply to lost offspring with a haunting howl. There is no record of groups communicating vocally. If an threat is sensed, all lemuroids in the area are alerted without vocalizations. They congregate in a group, back to back, maintaining physical contact with each other.

Both sexes of Hemibelideus lemuroides secrete a cream colored fluid, which they rub over themselves. Secretions, accompanied by a strong musky odor, are stimulated when lemuroids are disturbed or handled. This may be a form of communicating identity, reproductive state, or other factors.

Lemuroid ringtail possums have large, forward facing eyes adapted to night vision. It is assumed that through vision they locate food, predators, and fellow possums. (Burnie and Wilson, 2005; Flannery, 1994; Winter, 1995)

Food Habits

Lemuroid ringtail possums forage, on average, 16 m above the ground. They are almost exclusively folivorous, specializing in low fibrous leaves, with little variation. Lemuroid ringtail possums eat leaves only from a handful of tree species, preferring young foliage. Preferred tree species are Queensland maple (Flindersia brayleyana), brown quandong (Elaeocarpus ruminatus), and bollywood (Litsea leefeana). If there are no young leaves to be eaten they take mature leaves from their preferred trees, as opposed to eating young leaves from another species. Lemuroid ringtail possums eat other parts of trees as well, particularly the flower buds from brown bollywood (Litsea leefeana) and the fleshy covering of yellow walnut (Beilschmiedia bancroftii). (Burnie and Wilson, 2005; Flannery, 1994; Laurance, 1990; Winter, 1995)

  • Plant Foods
  • leaves
  • wood, bark, or stems
  • seeds, grains, and nuts
  • flowers

Predation

Carpet pythons (Morelia spilota) and rufous owls (Ninox rufa) are the only known predators of Hemibelideus lemuroides. Both predators hunt these possums in the forest canopy.

Lemuroid ringtail possum families band together in a tight cluster when they sense danger. This may dissuade predators from engaging due to sheer numbers. Also, this allows adults to keep their young safely in the pack's middle. (Laurance, 1990; Winter, 1995)

Ecosystem Roles

Lemuroid ringtail possums may disperse the seeds of some of the fruits they eat. (Laurance, 1990; Winter, 1995)

  • Ecosystem Impact
  • disperses seeds

Economic Importance for Humans: Positive

There are no known positive effects of Hemibelideus lemuroides on humans.

Economic Importance for Humans: Negative

There are no known adverse effects of Hemibelideus lemuroides on humans.

Conservation Status

The status of H. lemuroides is stable, but precarious. Populations currently seem healthy but the habitats that they depend on have so far been spared from extensive logging. Lemuroid ringtail possum populations decreased by 97% in secondary forests compared to primary. This is probably because of their reliance on old trees for dens, their reliance on the leaves of only a few, slow-growing tree species, and their preference for high, continuous forest canopies. Any threat to their primary forest habitats will severely threaten their populations. (Laurance, 1990; Winter, 1995)

Other Comments

Hemibelideus literally translates as "half-glider" ('belideus' being a diminutive form of Petaurus, meaning "glider"). It was once thought that Hemibelideus lemuroides were gliding possums. (Flannery, 1994; Winter, 1995)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Jennifer Humfleet (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

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).

monogamous

Having one mate at a time.

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.

scent marks

communicates by producing scents from special gland(s) and placing them on a surface whether others can smell or taste them

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

social

associates with others of its species; forms social groups.

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

Baverstock, P., M. Krieg, J. Birrell, G. Mckay. 1990. Albumin immunological relationships of Australian marsupials: the pseudocheiridae. Australian Journal of Zoology, 38/5: 519-526.

Burnie, D., D. Wilson. 2005. Animal: The Definitive Visual Guide to the World's Wildlife. New York: DK Publishing, Inc.

Flannery, T. 1994. Possums of the World: A Monograph of the Phalangeroidea. Australia: GEO Productions Pty Ltd.

Holz, P. 2002. "Restraint and Anesthesia of Possums" (On-line). Accessed March 19, 2006 at http://www.ivis.org/special_books/Heard/holz5/ivis.pdf.

Jackson, S. 2000. Glide Angle in the genus Petaurus and a Review of Gliding in Mammals. Mammal Review, 30/1: 9-30.

Johnson-Murray, J. 1987. The comparative myology of the gliding membranes of Acrobates, Petauroides, and Petaurus contrasted with the cutaneous myology of Hemibelideus and Pseudocheirus (Marsupialia: Phalangeridae) and with selected gliding rodentia (Sciuridae and Anomaluridae). Australian Journal of Zoology, 35/2: 101-113.

Laurance, W. 1990. Comparative Responses of Five Arboreal Marsupials to Tropical Rainforest Fragmentation. Journal of Mammalogy, 71/4: 641-653.

Lindenmayer, D., R. Lacy. 1995. Metapopulation Viability of Arboreal Marsupials in Fragmented Old-growth Forests: Comparison Among Species. Ecological Applications, 5/1: 183-199.

Smith, A., I. Hume. 1984. Possums and Gliders. Australia: Surrey Beatty & Sons Pty Limited.

Vaughan, T., J. Ryan, N. Czaplewski. 2000. Mammalogy. U.S.A.: Thomson Learning, Inc.

Winter, J. 1995. Lemuroid ringtail possum. Pp. 238-239 in R Strahan, ed. Mammals of Australia. Australia: Reed Books.

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