General information

Kangaroos are marsupials and belong to the Family Macropodidae (i.e. big feet) that is grouped with the Potoroidae (potoroos, bettongs, rat-kangaroos) and Hypsiprymnodontidae (musky rat-kangaroo) in the Super-Family, Macropodoidea. This comprises around 50 species in Australia and a dozen or more in New Guinea. Some of the smaller species, such as Yellow-footed Rock-Wallabies, Burrowing Bettongs, accompanied Pig-footed and Golden Bandicoots, Bilbies and possibly Hairy-nosed Wombats into extinction with the advent of pastoralism. However, the largest species remain in much of their original range with the grey kangaroos expanding inland as grazing habitat increased and coastal habitat was lost in clearance for agriculture. The defining feature of the kangaroo family is that they are the largest vertebrates to hop (both currently and from what we know from palaeontology).

The Rock-wallabies (Petrogale spp.) is the most diverse genus amongst the living macropods with 16 species ranging from 1 to 12 kg in size. They are found across mainland Australia and on some recently separated offshore islands but not on the Bass Strait Islands, Tasmania or New Guinea. The species diversified from a common ancestor about 4 million years ago and their closest affinity to other macropods is with the Tree-kangaroos. Diversification of species occurred in two waves. The first gave rise to the Short-eared Rock-wallaby, the Monjon, the Narbelek, the Yellow-footed Rock-Wallaby and the Proserpine Rock-wallaby. The second was about a million years ago and lead to species that are not all morphologically distinctive like those along the Queensland seaboard. All Rock-wallabies favour habitat with rocky outcrops and slopes, cliffs and gorges or are found on boulder piles and escarpments especially in the wet-dry tropics. Their ability to scale precipitous rock faces in leaps that appear to defy gravity comes from adaptations to the feet and tail. The feet are short relative to the majority of macropods that inhabit flat ground. The pads are thick, spongy and highly granulated so that they compress on the rock surface and maximise grip. The tail is long and cylindrical with little taper and great flexibility. The tail acts as a counterbalance and rudder in rapid hopping across uneven surfaces and allows changes of direction in mid-air.

Species

Cape York Rock-wallaby

Petrogale coenensis ('Coen rock-weasel')

Best place to see

Mungkan Kandju (Kaanju) National Park, Queensland

The Mungkan Kandju National Park is a large wilderness area (457, 000 hectares) between the Archer and Coen Rivers and includes part of the McIlwraith Range foothills. The Cape York Rock-wallaby is associated with the eastern side of Cape York but several populations are found around the township of Coen and so it is likely to be in this nearby National Park. The Park is only accessible by 4WD vehicle and is likely to be closed in the Wet season (austral summer). Coen is about 8-10 h drive from Cairns along the Peninsula Development Road. The ranger station at Rokeby is a further 1.5 -2 h drive to the west of Coen. Accommodation within the park is bush camping at several sites and so visitors need to be entirely self-sufficient. There are a limited number of bush tracks for driving and walking out from campsites is recommended taking into account that water bodies are inhabited by estuarine crocodiles. To orient yourself, Queensland National parks provides an excellent map of the Cape York National Parks.

The Park has other macropods including Antilopine Wallaroos and Agile Wallabies along the watercourses.

Identification

Males to 5 kg and females to 4.2 kg. The Cape York Rock-Wallaby and Godman's Rock-wallaby are generally similar and share a number of external characteristics with the Unadorned and Allied Rock-wallaby. Most Cape York and Godman's Rock-wallabies are more yellow-brown on the limbs, head and around the base of the tail than any of the species. Godman’s rock wallaby has a faint dark stripe across the side to face beginning at the nose and passing through the eye to the base of the ear. This stripe is bordered by another indistinct yellowish one which is not always apparent. The Cape York Rock-wallaby tends towards the pale buff-coloured cheek-stripe. Both species have a central narrow dark brown stripe from about the eye level to the back of the head extending to the upper part of the back in the Cape York Rock-wallaby. The chest and belly are a sandy brown to greyish yellow. This is variable and one specimen had light underparts counter pointed by mottled brown. The distal third to half the tail is grey-white with a darker base. In some specimens the terminal part of the tail is silvery white. The density of hairs increases at the tail tip but there is little or no terminal brush.