Ring-Tailed Rock Wallaby (Petrogale xanthopus) of Australian Lands "Down Under"

Wallabies are native to Australia and New Guinea and welcome in zoos worldwide. They belong to the family Macropodidae within the mammalian infraclass Marsupialia. Macropods can be recognized by their long (μακρός, makros) footed (πούς, pous) appearance (εἶδος, eidos). Marsupials distinguish themselves by a frontal pouch (μαρσύπιον, marsupion) for carrying their young and their possession of longer hind limbs than forelimbs. They do not restrict their ranks to macropods since marsupials include among their numbers:

• Bandicoots;
• Bettongs;
• Bilbies;
• Koalas;
• Numbats;
• Opossums;
• Possums;
• Quolls;
• Tasmanian devils;
• Wombats.

In contrast, the term macropod does apply to such fellow marsupials as:

• Kangaroos;
• Wallaroos.

The ring-tailed, yellow-footed rock-wallaby emerges as one of the most agile, attractive examples of the macropodal marsupial.

Not all wallabies are found in the exact same habitats. The wallaby that accepts sylvan lifestyles in the forest carries one of two common names:

• Dorcopsis (from the ancient Greek words δορκας [dorkas] for “gazelle” and ὄψις [opsis] for “appearance, sight, view”]);
• Pademelon (from the aboriginal term badimaliyan which the Dharug and Eora peoples of what is nowadays the greater Sydney area used to identify the “small kangaroo of the forest"). 

A hare-wallaby endures the challenges of life in open grasslands whose protective ground cover can be punctuated by sandy desert dunes and plains. The nail-tail wallaby experiences the denser vegetation inherent in grass-, scrub-, shrub- and wood-lands. Rock-wallabies manage to survive in rocky, rugged, steep landscapes. 

Ring-tailed, yellow-footed rock-wallabies carry the scientific name Petrogale xanthopus. The genus name Petrogale comes from the combination of the ancient Greek words πέτρα (petra) for “cave, cliff, ledge, ridge” and γαλέη (galeē) for “weasel.” The species name xanthopus derives from the ancient Greek terms ξανϑóς (xanthós) for “yellow” and πούς (pous) for “foot.” Yellow-footed ring-tails owe their niche within the taxonomic system consolidated by Swedish super-scientist Carl Linnaeus (May 23, 1707 – January 10, 1778) to the scientific expertise of John Edward Gray, FRS (February 12, 1800 – March 7, 1875) in 1855. The Walsall-born zoologist was Keeper of Zoology at the British Museum (1840 – 1874). He was respected for investigations regarding:

• Fish;
• Insects;
• Mammals;
• Molluscs;
• Postage stamps;
• Reptiles.

Modern zoologists accept two subspecies of ring-tailed rock-wallabies. Proper scientific procedure asks for a nominate type species and subspecies. With the equivalent of “poster animal” status, the nominate subspecies gets as a third name a repetition of the species name: Petrogale xanthopus xanthopus. The non-nominate subspecies has the complete trinomial (“three-name”) designation Petrogale xanthopus celeris. The Latin word celeris honors the subspecies as “fast, swift.” It originates in the Latin verb cellō, which means “to impel, to urge forward” and which reflects a borrowing from the ancient Greek word κέλλω (kellō) for “to drive on, to put to harbor, to put to shore.” Variations in geographical distribution and pelt colors separate the two subspecies of ring-tailed rock-wallabies. 

A white stripe running from the dark snout and under the big, dark eyes accentuates the cheeks of both long-, silky-haired subspecies. It brightens the mouth, whose flat-topped, grinding-friendly, low-crowned dental formula is as follows:

• 3 incisors, 1 canine, 2 premolars, and 4 molars per left and right upper jaw;
• 1 incisor, 2 premolars, and 4 molars per left and right lower jaw.

A dark streak connects the space between each tawny-backed ear with the mid-back. Clean white and gentle grey-brown respectively cover the under- and upper-sides. Darker and lighter tawny stripes define the brown- or white-tipped tail. A white-streaked tawniness dominates large hind feet, powerful legs, and shortened forearms. Each extremity harbors a dark-tipped, short-clawed paw.

Mature sizes are as follows:

• Height 3.3 – 4.3 feet (1.01 – 1.31 meters);
• Length:  head/body 19 – 26 inches (48.26 – 66.04 centimeters); hind foot 4.75 - 6.75 inches (12.1 - 17.14 centimeters); tail 22 – 28 inches (55.9 – 1.12 centimeters);
• Weight 13 – 26 pounds (5.9 – 11.79 kilograms).

Adults can mate year-round even though embryonic development temporarily halts during:

• Drought;
• Joey-occupied frontal pouches.

Generally between April and September, mothers-to-be deliver one furless, 0.5 – 0.75-inch (1.27 – 1.91-centimeter), 0.02-ounce (500-milligram) joey after a 31 – 32-day gestation. The newborn -- blind the first month -- follows maternal saliva trails to frontal pouch-living. Mothers generate two types of milk:

• In-pouch, 189 – 227 days;
• Out-of-pouch, 30+ days until weaning.

Sexual maturity occurs at 540 – 590 days. 

Ring-tailed rock-wallabies adhere to extended-family living during lifetimes estimated at 3 – 18 years. Related families of a husband, 2 wives, and 3 joeys comprise 20 – 100-member neighborhoods at:

• Caves;
• Crevices;
• Ledges.

They emerge to:

• Balance with forearms held at right angles and tail serving as anchor;
• Climb steep cliffs and tree trunks;
• Drink 10+% of their body weight in 7 minutes during downpours;
• Eat bark, forbs, fruits, grasses, herbs, roots, shoots, twigs at dawn and dusk;
• Grind rocks glossy-smooth with their coarse, hair-fringed, rough foot pads;
• Jump across 12+-foot (3.06+-meter) chasms;
• Stand rigidly while stamping their feet to communicate invasions and threats;
• Sunbathe.

Alone among mammals, ring-tails know how to transfer water from one mouth to another.

Some specialists accept a total ring-tail population of 2,000. Within an estimated 386-square mile (999.74-square kilometer) range, female and male ring-tailed rock-wallabies appreciate respectively overlapping home ranges of:

• 225 – 437 acres (91.05 – 176.85 hectares) in summer and 239 – 568 acres (96.72 – 229. 86 hectares) in winter;
• 467 – 568 acres (188.99 – 229.86 hectares) in summer and 427 – 494 acres (172.80 – 199.91 hectares) in winter.

The collective well-being of ring-tailed, yellow-footed wallaby populations asks for habitats that guarantee:

• Abundance of bendee and mulga (Acacia spp) leaf litter, forbs (Sida filiformis), rock sedges (Scleria sphacelata), and tufted grasses (Sporobolus caroli);
• Conglomerate, granite, limestone or sandstone rocky outcrops;
• Sources of permanent freshwater within 3 miles (4.82 kilometers) of the family home. 

The ring-tailed rock-wallaby’s nominate subspecies considers as home:

• Buckaringa Wildlife Sanctuary as well as Flinders, Gawler and Olary Ranges in central and eastern South Australia;
• Coturaundee and Gap Ranges as well as Mootwingee National Park in western New South Wales.

The second subspecies, Petrogale xanthopus celeris -- whose pelage expresses paler colors and whose tail is less distinctly banded -- still colonizes the Adavale Basin in southwestern Queensland. The spatially distinct geographical distribution nevertheless offers similar life-threatening challenges:

• Competition from domesticated, introduced and wild goats, rabbits and sheep;
• Death in wildfires;
• Predation from dingoes (Canis lupus dingo), European foxes (Vulpes vulpes), and wedge-tailed eagles (Aquila audax).

Fortunately, private and public endeavors merge to preserve Australia’s ring-tailed rock-wallabies.

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

Lowry Park Zoo, Tampa, Florida: Trish Hartmann (trishhartmann), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/21078769@N00/8350400981/

Marsupialia distribution map: Nrg800, CC BY-SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Yellow-footed_Rock_Wallaby.png

John Gould, Mammals of Australia (1863), Vol. II, Plate 43: Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Petrogale_xanthopus.jpg

Adelaide Zoo, southeastern South Australia state, south central Australia: Bahudhara, CC BY SA 3.0, via Wikimedia Commons @ https://en.wikipedia.org/wiki/File:Yellow-foot_with_joey.JPG

Mutawintji National Park, Far West region, New South Wales, southeastern Australia: Doug Beckers, CC BY SA 2.0, via Flickr @ https://www.flickr.com/photos/dougbeckers/3552897327/

John Gould, Mammals of Australia (1863), Vol. II, Plate 44: Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/49740817

Proceedings of the Zoological Society of London, Vol. 1, Plate XXXIX: Public Domain, via Biodiversity Heritage Library @ https://www.biodiversitylibrary.org/page/37027985

Monarto Zoo, southeastern South Australia state, south central Australia: Rhys Moult, CC BY SA 2.0, via Flickr @ https://www.flickr.com/photos/13491599@N03/7182962415/

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