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

Mareeba Rock-wallaby

Petrogale mareeba ('Mareeba rock-weasel')

Best place to see

The Mareeba Rock-wallaby is patchily distributed through a region of North Queensland west of Port Douglas roughly bounded by Mount Carbine in the east, the Undara Lava tubes in the west and Mount Garnet in the south. Mount Carbine is the nominated 'best-place-to-see' and just to the west of the Daintree National Park. However, most people will have a very close encounter at Granite Gorge close to Mareeba in the Atherton Tablelands. There is a nature park on Harrington Road.

Identification

Males average 4.5 kg and females average 3.8 kg.  The Mareeba Rock-wallaby is part of a complex of species that includes the Sharman's Rock-wallaby, the Unadorned Rock-wallaby and the Allied Rock-wallaby. These species are not easily distinguished except by the shape and number of chromosomes. The genera tourist does not have a cytologist's kit to make such distinctions and so locality is the best guide to determine which species you are seeing. Freshly moulted individuals are typically greyish on the back but as the year advances the colour changes to pale through to dark brown.  Some individuals are almost black. The underside of the the body and limbs is lighter and typically a sandy brown. There is a pale cheek stripe, with indistinct and patchy  markings behind the shoulders and a dark dorsal stripe along the crest of the head. The paws and feet are dark and the tail darkens towards the tip which has an indistinct dirty white brush.

Habitat

The Mareeba Rock-wallaby seems to prefer more open habitat than some of the other Queensland rock-wallabies. It is most often found in rocky habitat embedded within open forest and grassy woodland and less often in the thicker vine forests.

 

Foraging behaviour

Foraging behaviour studies on this species have focused on the Granite Gorge population where hand-feeding by tourists occurs. The provisioning of wildlife to improve their viewability occurs in many wildlife destinations around the world. It is more likely to occur in private reserves than national parks and the latter often have policies against wildlife feeding. Even so artificial water bodies may be constructed and provisioned with viewing infrastructure (from seating to hides) in national parks. Wildlife Tourism Australia has a policy 'Tourist Wildlife Interactions' that includes discussion of wildlife feeding. In general, wild animals do not remain 'wild' if provisioned directly by people. This is the case for the Mareeba Rock-wallabies at Granite Gorge which have become habituated to people. Their behaviour has been altered so that they are active in the open earlier than non-provisioned populations, both aggressive and affiliative behaviour (allo-grooming) are heightened, and they tend be more active. Even so the general condition of the rock-wallabies is sound.

Reproductive behaviour

The reproductive behaviour of this species has not been described but they are likely polygamous since they live in large colonies. They are also likely to breed throughout the year with a possible concentration of large pouch young and young-at-foot in months that typically receive the highest rain.

Social organisation

Rock-wallabies are typically social and live in colonies varying from a few individuals to over 100. The Mareeba Rock-wallaby appears to be at the latter end of the scale with colonies of up to fifty making it amongst the most social of the macropods.

Further readings

Eldridge MDB, Close RL (1997) Chromosomes and evolution in rock-wallabies, Petrogale (Marsupialia: Macropodidae). Australian Mammalogy 19, 123-135.

Hodgson AJ, Marsh H, Corkeron PJ (2004) Provisioning by tourists affects the behaviour but not the body condition of Mareeba rock-wallabies (Petrogale mareeba). Wildlife Research 31, 451-456.