The common ringtail possum (Pseudocheirus peregrinus, Greek

Ancient Greek

Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 for "false hand" and Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 for "pilgrim" or "alien") is an Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

n marsupial

Marsupial

Marsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...

. It lives in a variety of habitats and eats a variety of leaves of both native and introduced plants, as well as flowers and fruits. These dietary factors have, over time, aided burgeoning introduced (pest) populations in New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. This possum

Possum

A possum is any of about 70 small to medium-sized arboreal marsupial species native to Australia, New Guinea, and Sulawesi .Possums are quadrupedal diprotodont marsupials with long tails...

 also consumes a special type of faeces that is produced during the daytime when it is resting in a nest. This behaviour is called coprophagia

Coprophagia

Coprophagia or coprophagy is the consumption of feces, from the Greek κόπρος copros and φαγεῖν phagein . Many animal species practice coprophagia as a matter of course; other species do not normally consume feces but may do so under unusual conditions...

 and is similar to that seen in rabbits.

Taxonomy

The common ringtail possum is currently classified as the only living species in the genus Pseudocheirus

Pseudocheirus

Pseudocheirus is a genus of ringtail possums . It includes a single living species, the Common Ringtail Possum of Australia, as well as the fossil Pseudocheirus marshalli from the Pliocene of Victoria.Other species have previously been included in this genus...

; the species of Pseudochirulus

Pseudochirulus

Pseudochirulus is a genus of marsupial in the Pseudocheiridae family native to Indonesia, Papua New Guinea and Queensland, Australia.It contains the following species:*Lowland Ringtail Possum, Pseudochirulus canescens...

and other ringtail genera were formerly also classified in Pseudocheirus. Several subspecies have been described, such as the Western Australian Pseudocheirus peregrinus occidentalis, but the entire population may be a species complex

Species complex

A species complex is a group of closely related species, where the exact demarcation between species is often unclear or cryptic owing to their recent and usually still incomplete reproductive isolation. Ring species, superspecies and cryptic species complex are example of species complex...

.
The arrangement as the only extant species of Pseudocheirus is:

• Pseudocheirus peregrinus pereginus, the type subspecies based on a collection made at Endeavour River
  Endeavour River
  The Endeavour River on Cape York Peninsula in Far North Queensland, Australia, was named in 1770 by Lt. James Cook, R.N., after he was forced to beach his ship, HM Bark Endeavour, for repairs in the river mouth, after damaging it on Endeavour Reef...
  
  
• Pseudocheirus peregrinus convolutor,
• Pseudocheirus peregrinus pulcher,
• Pseudocheirus peregrinus occidentalis, called the western ringtail possum, found in the south west of the country. Taxonomic opinion favours regarding this as a separate species, Pseudocheirus occidentalis, though the currently contradictory evidence would not allow this recommendation to be formalised.

Description

The common ringtail possum weighs between 550 and 1100 g. It has grey fur with white patches behind the eyes and usually a cream coloured belly. It has a long prehensile tail which normally displays a distinctive white tip over 25% of its length. The back feet are syndactyl which helps it to climb. The molar teeth of the ringtail possum is similar to that of the koala

Koala

The koala is an arboreal herbivorous marsupial native to Australia, and the only extant representative of the family Phascolarctidae....

 and the greater glider

Greater Glider

The Greater Glider is a small gliding marsupial found in Australia. It is not closely related to the Petaurus group of gliding marsupials but instead to the Lemur-like Ringtail Possum , with which it shares the subfamily Hemibelideinae.The Greater Glider is nocturnal and is a solitary herbivore...

 with the four major cusps being shaped into crescentic blades.

Range and habitat

Common ringtail possums are found along the eastern coastline of Australia, Tasmania, and the south-western corner of western Australia. They generally live in temperature and tropical environments and are rare in drier areas. Ringtail possums prefer forests of dense brush. The common ringtail possum and its relatives occupy a range of niches in a matter similar of lemurs, monkeys, squirrels, and bushbabies in similar forests on other continents.

Diet and foraging

The common ringtail possum prefers to feed on Eucalyptus

Eucalyptus

Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...

foliage and the highest densities of ringtail possums are found in areas where Eucalyptus are found. However, ringtail possums will eat foliage, flowers and fruits from other species of trees and shrubs from the lower levels of the forest. When foraging, ringtail possums prefer young leaves over old ones. One study found that young possums emerge from the pouches when the flush of plant growth and the flowering and fruiting of the tea-tree, Leptospermum

Leptospermum

Leptospermum is a genus of about 80-86 species of plants in the myrtle family Myrtaceae. Most species are endemic to Australia, with the greatest diversity in the south of the continent; but one species extends to New Zealand, another to Malaysia, and L. recurvum is endemic to Malaysia.They...

. Young eucalypt foliage have a higher concentration of nitrogen and lower cell-wall concentration than older leaves and the higher concentrations of tannins make the protein less available. When feeding, the possum’s teeth cuts the leaves in very small pieces. Much like the koala and the greater glider, the common ringtail possum has a large caecum which is where the fine coarse particles that are separated. These particles are retained in the caecum for up to 70 hours. Here, massive colonies of micro-organisms attach to the tissue components and cause partial digestion of cells walls and tanned cytoplasts.

What distinguishes the system of the digestive system of the common ringtail possum from that of the koala and the greater glider, is the caecal content is taken directly back to the stomach, where they go on a second passage through the gut. Because of this, the ringtail possum gains far greater access to protein and the energy products of bacterial fermentation in its caecum. This is also done by lagomorphs like rabbit

Rabbit

Rabbits are small mammals in the family Leporidae of the order Lagomorpha, found in several parts of the world...

s and pika

Pika

The pika is a small mammal, with short limbs, rounded ears, and short tail. The name pika is used for any member of the Ochotonidae, a family within the order of lagomorphs, which also includes the Leporidae . One genus, Ochotona, is recognised within the family, and it includes 30 species...

s. Hard faeces are produced during the night while foraging and are not eaten, while soft faeces are produced during the day while resting have been recorded being taken directly from the cloaca.

Metabolism

The re-ingestion of caecal content also serves to maintain the ringtail possum’s energy balance. Ringtail possum seem to prefer Eucalyptus andrewii over other species and feed almost exclusively on it in captivity. When consuming these plants, ringtail possums gain the much of their gross energy from reingestion. The the common ringtail possum has a daily maintenance nitrogen requirement (MNR) of 290 mg N/kg^0.75, similarly to the koala but is half the requirements of the greater glider. Still, common ringtail possums gain much of their MNR from consuming their nitrogen-rich caecal pellets. A ringtail possum would need to obtain 620 620 mg N/kg^0.75 if it did have this additional access to metabolic nitrogen. For the ringtail possum, 96% of the urea that is produced in the liver is recycled into the caecum and is then synthesised into bacterial protein from there. However, this is only useful with re-ingestion since the bacterial protein must be digested in the stomach and the amino acids in the small intestine. By recycling urea, the ringtail possum also conserves water. Instead of being released as urine, some of the water is returned to the stomach in the caecal pellets. Ringtail possums get most of their water intake from the free water in the leaves they eat which is supplemented with drinking water. Re-ingestion is thus important in water conservation and for feeding on Eucalyptus leaves which have a nitrogen content of only 1.1%. It is particularly important during late lactation which requires 1.4 g of protein to be export each day in milk to support the growth of the young.

Behaviour and life history

Common ringtail possums are mostly nocturnal and are well adapted to arboreal life. They are rarely found on the ground and use their prehensile tail extensively. They have been known to communicate with soft, high-pitched, and twittering calls.

Nesting

Common ringtail possums live a gregarious lifestyle that is centred around the communal nests. Ringtail possums build nests called greyer in the branches of trees or in large tree hollows. A communal is made up of an adult male with one or two adult females, their dependant offspring and immature offspring of the previous year. A group of ringtail possums may build several greyer at different heights and localities. Ringtail possums are territorial and will drive anyway any strange conspecifics from their nests. A group has a strong attachment to their site. In one experiment, a group was removed from their territory and it was not recolonised for the next two years. Ringtail possum nests tend to be more abundant in low scrub or areas regenerating after partial clearance and are less abundant in heavy timbered country with sparse under-story. Greyers are an important element in the survival of the young after they relinquish their mother’s back. They also serve as a daytime refuge for adults.

Reproduction and growth

Common ringtail possums are marsupials, thus they carry their young in a pouch while they develop. Depending on the location in Australia, the mating season can take takes place anywhere between April and December. The majority of the young are born between May and July. The ringtail possum has an estrous cycle lasting 28 days. It is both polyestrous and polyovular. If a female prematurely loses her liter, she can return to oestrous and produce a second litter in October as a replacement if conditions are right. The average number of young in a litter is two, although four young can be reared as the female has four teats in her pouch. Usually two of the four nipples are functional at one time and pouch has a forward facing opening and. Initial growth of the common ringtail possum young is generally slow. This slow growth occurs during the period when the weight of the female is at its lowest. The slow growth rate is due to the quality of the milk being providing to the young. As with other marsupials, the common ringtail possum’s milk changes through lactation. In comparison with the milks of other marsupial species, ringtail possum milk is relatively dilute and low in lipid. During the second phase of lactation solids represent around 16% (w/w) and increases to 25% (w/w) when the young first emerges from the pouch. During this time, concentration of carbohydrates declines while concentrations of protein and lipid peak. The long lactation of the ringtail possums may provide the young the opportunity to learn skills in the communal nest and develop their ability to climb and forage in the trees.

The young both open their eyes and are able to make clear vocalisations, between 90 and 106 days after birth,. The young emerge from their mother's pouch 120–130 days after birth. However, lactation generally does not stop until 180–220 days after birth and sometimes ends as early as 145 days. Both sexes become sexually mature in the first mating season after their birth.

Status

Common ringtail possum populations severely declined during the 1950s. However, populations seem to have recovered in current times. Because they are almost exclusively arboreal, common ringtail possums have loss a lot of habitat due to deforestation in Australia. Ringtail possums are vulnerable to being struck by cars, or hunted by cats and dogs in suburban areas. This species do not adversely affect humans. Ringtail possums do not nest within homes or human structures and as such are not considered pests.