Cinereus Ringtail Possums (Pseudochirulus cinereus) of Daintree River in Queensland, Australia

Geographical distribution accounts for the common name Daintree River ringtail possum. Daintree ringtails naturally can be found nowadays in Australia in northeastern Queensland at:

• The Carbine Tablelands;
• The Mount Windsor Tablelands;
• The Thornton Peak massif.

So the current configuration of their native lands centers on territory to the:

• North of the port city of Cairns;
• South of Cape Tribulation.

It therefore draws upon the atmospheric humidity and terrestrial moisture inherent in near-coastal tropical locations. It falls within the Daintree River watershed. It includes the Daintree River National Park. It is protected by the Wet Tropics World Heritage Area designation conferred upon northeastern Queensland by the World Heritage program administered through the United Nations Economic and Social Council.

Another common name, cinereus ringtail possum, acknowledges the marsupial mammal’s binomial (“two-name”) designation and physical appearance. The Daintree ringtail’s taxonomic name, Pseudochirulus cinereus, attributes importance to two physical traits. The genus name comes from the ancient Greek words for “false hand.” It describes the Daintree ringtail possum’s forepaws, each of whose first two digits is (human-like) opposable to the other three. A hallux (“big toe”) functions as the sole opposable digit on each rear paw. The sharp, short claws on each paw help to project an ashy grey impression, which is reinforced by parts of the Daintree ringtail’s body, head and tail. The species name cinereus in fact is from the same-spelled Latin word for “ashen grey.” 

The taxonomic niche of Daintree ringtails arises from their first official description and subsequent revisions. It first and foremost benefits from English-born American botanist and zoologist George Henry Hamilton Tate’s (April 30, 1894 – December 24, 1953) examination of skins and skulls while curating mammalogy collections at New York City’s American Museum of Natural History in 1945. His identification depicts Daintree ringtails as having:

• Darkly-striped down the middle of the backs and heads;
• Dense, light brown, woolly fur;
• Pointed, Roman-nosed snouts;
• Prehensile tails whose tips ring-curl and undersides showcase hairless friction pads.

Subsequent research differentiates Daintree ringtails as:

• A distinct species in 1989 by chromosomal number and interbreeding impossibilities;
• Previously misnamed Pseudocheirus canescens, per Timothy Flannery in 1994.

Inexperienced wildlife-lovers can fumble when attempting to distinguish between Daintree River, Herbert River (Pseudochirulus herbertensis), and lemur-like (Hemibelideus lemuroides) possums. But the confusion over proximitous geographical distributions and subtle physical similarities dissipates with experience in inspection and with images. For example, Daintree ringtails favor altitudes -- 1,377.95+ feet (420+ meters) -- which begin at higher elevations than those of Herbert River and lemur-like possums, at 1,148.29+ feet (350+ meters) and 1,312.34+ feet (400+ meters) respectively. Daintree ringtail possums indeed lead arboreal-dominated life cycles devoted to foraging and foraying through the high canopies of tall trees in:

• Cool wet rainforests;
• Primary and secondary tropical forests;
• Wet sclerophyll (“hard leaf”) forests with eucalypt (Eucalyptus spp) overstories and rainforest understories.

Predatory wedge-tailed eagles (Aquila audax) haunt the above-mentioned tracts of continuous canopy in rainforests. But forested elevations in fact let Daintree ringtails practice active avoidance of eagles, owls, and pythons. Canopy connectivity permits Daintree ringtails to:

• Feed on nocturnally-available flowers, fruits, and leaves within home ranges of 7.41 – 49.42 acres (3 – 20 hectares);
• Hide and sleep in diurnally-available, singly-occupied branch-bolstered nests and leaf-lined hollows;
• Raise offspring through single-parent arrangements;
• Select solitary lifestyles within communities in which all Daintree ringtails receive individual shelters and space. 

It nevertheless provides no protection from the endoparasites from which Daintree ringtails may suffer. Researchers indeed suspect as internally-located parasites of Daintree ringtails:

• Cestode flatworms (Platyhelminthes phylum);
• Nematodes (Nematoda phylum);
• Protozoans (Protista kingdom).

April and May comprise peak months in year-round breeding seasons. One litter of 2 offspring gets produced yearly. Males probably lack parental involvement since female nests only are:

• Conjugal for mating adults;
• Familial for pre-adult offspring.

Newborns lead pouch-confined lives for 4 -5 months. They then let foraying on their mother’s back alternate with waiting on branches during maternal foragings. They may be considered:

• Weaned at 5 – 6 months and weights of 9.88 ounces (280 grams);
• Independent at 10 months;
• Sexually mature at 18 – 24 months.

Adult head-and-body lengths measure 6.57 – 14.49 inches (167 – 368 millimeters). Adults weigh from 24.69 - 42.33 ounces (700 – 1,200 grams) as females to 29.28 – 51.15 ounces (830 – 1,450 grams) as males.

In comparison to a record 15 years for a female in captivity, researchers accord Daintree ringtails life expectancies of 4 – 5 years in the wild. Dominating communication, nutrition and sanitation skills contributes to Daintree ringtail survival. Communication apparently does not involve sounds since Daintree ringtails only vocalize as pre-adults separated from their mothers. It instead draws upon:

• Feces;
• Sternum gland-generated scents;
• Touch.

Fecal droppings in fact emerge as important communicators and energizers. They function as dietary supplements by being digested, processed by the caecum’s (entrance to large intestine) bacteria, and re-eliminated. Initial digestion of plant parts may give folivores (leaf-eaters) minimal nutrients. Re-digestion and re-elimination releases previously unavailable, now-soluble nutrients by recycling, reusing, and reducing environmental wastes. 

Low-energy, slow-moving Daintree ringtails elude observation and hopefully predation. They compare to conscientious objectors and pacifists in avoiding conflict and refraining from violence despite claws and grinding dental formulas of:

• 3 incisors, 1 canines, 3 premolars, and 4 molars per left and right upper jaws;
• 2 incisors, 3 premolars, and 4 molars per left and right lower jaws.

How many succumb to natural enemies is unknown since predation happens in high canopies and Daintree ringtail predators leave no residue. But there may be strong reason to believe in Daintree ringtail sustainability since the somewhat ghostly-looking diprotodonts (“two forward-projecting teeth”) ghost habitats cherished by Queenslanders and World Heritage staff for:

• Ecological diversity;
• Environmental importance;
• Evolutionary insights;
• Natural beauty.

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

foreshore promenade, Cairns: Jorge Láscar (Jorge Lascar), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/8721758@N06/4560383576/

Distribution data from IUCN Red List: Chermundy/ IUCN Red List of Threatened Species, species assessors and the authors of the spatial data, CC BY SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Cinereus_Ringtail_Possum_area.png

Campfire scar on A. concolor, P. benthamiana, P. lambertiana, etc., forest floor, Snow Creek Trail, Yosemite National Park: Walter Siegmund (Wsiegmund), CC BY SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Campfire_scar_08319.JPG

Proceedings of Scientific Meetings of the Zoological Society of London for the Year 1884 (May 20), Plate XXX, between pp. 380-381
Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/28690271

Proceedings of Scientific Meetings of the Zoological Society of London for the Year 1884 (May 20), Plate XXXI, between pp. 380-381: Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/28690273

Wedge Tailed Eagle (Aquila audax), Australia's largest bird of prey: Thomas Schoch (Mosmas), CC BY SA 2.5, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Wedge_Tailed_Eagle.jpg

on the banks of the mighty Daintree: Daintree National Park, Queensland: robstephaustralia, CC BY 2.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:On_the_banks_of_the_mighty_Daintree.jpg

Mossman Gorge walking trail, Daintree National Park: Jorge Láscar (Jorge Lascar), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/8721758@N06/4560462410/; via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Lascar_Mossman_Gorge_walking_trail_-_Daintree_National_Park_(4560462410).jpg

Thornton Peak's summit overlooks Alexander and Cow Bay, Daintree National Park, Queensland: Goldenbowerbirds, CC BY SA 4.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Thornton_Peak,_Daintree_National_Park.jpg

view of Mount Sorrow, Cape Tribulation, northern Queensland: Laurel Lodged, CC BY-SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Mount_Sorrow,_Cape_Tribulation,_QLD.JPG

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