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).

 

Two of the four species of Hare-wallabies that were identified at European colonisation of Australia are extinct. The only species which retains a broad geographic range is the Spectacled Hare-wallaby which also has a small population is southern New Guinea. The genus was once common in the deserts and tropics and south-west of Western Australia. Pastoralism and the introduction of livestock grazing and concomitant changes in fire management and release of rabbits, foxes and cats have wrought a devastating impacts on the attractive small wallabies. A characteristic, emphasised in the Spectacled Hare-wallaby, is the rufous fur around the eye. The Hare-wallabies have long feet with long claws but the fore-limbs are very delicate and short.

Species

Spectacled Hare-wallaby (Barrow Island)

Lagorchestes conspicillatus conspicillatus ('spectacled hare dancer')

Best place to see

Barrow Island, Western Australia

Barrow Island was isolated from mainland Western Australia about 8,000 years ago by rising sea levels. It now forms Western Australia's second largest island (234 square kilometres) and is 56 km off the north-western coast about 1300 km from Perth. The process of isolation carried with it an ark of animal species. Amongst these are mammals that are threatened or extinct on mainland Australia. Isolation on Barrow Island of the Spectacled Hare-wallaby has lead to sufficient genetic drift to be recognised as a sub-species and in this case the type specimen of the species.  The island has three other macropod species - Boodie (burrowing bettong), Barrow Island Wallaroo, Black-footed Rock-wallaby - amongst its 15 species of mammals, as well as 110 species of birds, 54 species of reptiles and one species of frog. Green and Flatback turtles breed along its coastline.

In 1910, Barrow Island was declared a Class A Nature Reserve and was relatively pristine since it did not readily support pastoralism. Most exploitation was of marine resources such as turtles and peal oysters. However, in the 1950s oil was discovered but exploitation was delayed by the use of nearby Montebello Islands (about 16 km north) as an atomic testing site for the United Kingdom. This lead to the island's 'dubious' protection until the early 1960s when oil drilling commenced. By 1966 100 million barrels of oil had been produced and average production today is about 14,000 barrels with an expected lifetime through to 2020. Oil production has managed to be conducted with due environmental care over four decades without species loss. Even so impacts typical of human habitation and industry occur including roadkill, addition of water resources, nutrient outflows and the obvious excision of land for the oil industry. There is current concern about a large increment in industrial activity through the Gorgon Gas Project that will add a large-scale gas processing plant and associated equipment to the island.

Some general information about Barrow Island can be found at www.abc.net.au/nature/island/ep3/default.htm. Chevron Asiatic (www.chevron.com) operates the oil production and some counterviews about sustainability of the conservation values of the island can be found at www.rescuebarrowisland.org.au. The island is accessed from the port of Onslow, 88 km to the southeast.

Since access to Barrow Island is restricted, this destination is unrealistic for most tourists. The entry in 'The Mammals of Australia, 3rd Edition' by Burbidge and Johnson suggests the Spectacled Hare-wallaby remains common but patchily distributed in Queensland (the areas of tussock grasslands between Boulia and Mt Isa) and the Northern Territory (from the northern Tanami Desert to Arnhem Land but uncommon near the coast) but has much declined in Western Australia (Kimberley and Pilbara regions except Barrow Island). Thus the mainland subspecies is a better focus of a quest to see this species.

Identification

Male and female Spectacled hare-wallabies are of similar size. The Spectacled Hare-wallaby is the largest of the Hair-wallabies weighing up to 4.5 kg. The fur on the back is long and coarse with a dark-brown or black colour. However, the tips of the guard hairs are light given a silver-coloured appearance making this a very attractive species. The sides are reddish and light-tipped. The fur on the undersides is long and thick and a uniform slate-grey colour. The general colour years in a grizzled yellow grey. The head is grizzled white and black with a distinctive and well demarcated orange eye ring (the spectacles). The nose is less hairy than other species of Hare-wallabies and the terminal half of the nose and the edges of the nostrils are naked. The ears are very short and have a grizzled grey back. There are white stripes in front of and on the hips. The arms, forepaws, legs and feet are grey tinged with a variable colouring of red. The tail is marked by a thin colouring of pure white hairs.

Habitat

The Spectacled Hare-wallaby is found in tropical grasslands, especially tussock-forming species including spinifex, which may be overlain by a variety of vegetation (tall shrubland, open woodland, open forest in Queensland; Acacia shrublands and tropical savanna in the Northern Territory; spinifex grasslands in Western Australia). The tussocks provide protection and the hare-wallabies tunnel into these and may have several shelters in their home-range. The tussocks also provide thermoregulatory benefits under hot ambient temperatures. This refuge behaviour is coupled with exceptionally efficient physiological mechanisms to conserve water leading to one of the lowest water turnovers (5.3% of total body water per day) of mammals of its size. Its eco-physiology allows it to inhabit dry, hot climates and not drink free-water.

Foraging behaviour

  The diet of the Spectacled Hare-wallaby has been studied at a number of locations. The common denominator is a high consumption of grasses (65% in QLD, 66% in NT and the tips of spinifex on Barrow Island WA). The remainder of the diet is various herbs (forbs) like legumes which may provide more water in its diet than grasses. On Barrow Island it eats the seedlings of colonising shrubs. It may benefit from re-growth after fire if the burning is patchy. It is likely vulnerable to loss of tussock grassland habitat through frequent hot burns that are now common is pastoral regions. These large-scale burns further expose it to predation by feral cats. The home range estimated in a Queensland study at 177 ha is quite large, especially for an essentially solitary species and so densities are unlikely to be high.

Reproductive behaviour

Breeding can occur throughout the year. Gestation is 29-31 d and oestrus follows shortly after birth with post-partum mating. Embryonic diapause occurs in this species. Births are clumped on Barrow Island around the late Dry season (September) and towards the end of the Wet season (March). Pouch life is about 150 d and sexual maturity is reached within a year.

Social organisation

The species is typically solitary but small aggregations of around three individuals have been observed feeding in the same area. Thus home ranges are likely not exclusive and only shelter sites defended. THis deserves further study.

 

Further readings

Burbidge AA, Johnson PM (2008). Spectacled Hare-wallaby. In The Mammals of Australia 3rd Edition, (Van Dyck S, Strahan R eds.) pp. 314-316. (New Holland Reed, Chatswood).

Ingleby S, Westoby M (1992) Habitat requirements of the spectacled hare-wallaby (Lagorchestes conspicillatus) in the Northern Territory and Western Australia. Wildlife Research 19, 721-741.

Short J, Turner B (1991) Distribution and abundance of spectacled hare-wallabies and euros on Barrow Island, Western Australia. Wildlife Research 18, 421-429.