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 genus Macropus includes not only the large kangaroos but a range of mid-sized macropods known collectively at wallabies or brush wallabies. The exception is the Swamp Wallaby which is in its own genus Wallabia by virtue of its different chromosome number and other features. With the advent of agriculture and pastoralism the wallabies have fared less well than the kangaroos with most species in reduced ranges since European settlement. One species, the Toolache Wallaby (Macropus greyi) is extinct. In this pattern of range contraction, the Swamp Wallaby, is again an exception as it remains reasonably abundant in many peri-urban parks and reserves.

The Wallabies like the larger Kangaroos are predominantly grazers but may take some browse, especially the Swamp Wallaby. They share a similar body form and habits to the larger Kangaroos and are sympatric with Grey Kangaroos or the Antilopine Wallaroo in the north.

Species

Red-necked (Bennett's) Wallaby (Tasmania)

Macropus rufogriseus rufogriseus ('red-grey long-foot')

Best place to see

Narawntapu National Park, Tasmania

Narawntapu National Park in on the north coast of Tasmania within an hour's drive a Launceston, a major port of entry to the island State. Low coastal ranges back long Bass Strait beaches that include a complex of inlets, headlands and small islands. Habitat is diverse from uplands to coastal plains, wetlands, dunes and lagoons. With this diversity comes a rich fauna and flora. The density of macropods - Eastern Grey (Forester) Kangaroos, Red-necked Wallabies and Tasmanian Pademelons - grazing at dusk in the rich grasslands reminds visitors of the antelope herds of the Serengeti. The Park is thus an exceptionally good place to see the Tasmanian sub-species of the Red-necked Wallaby, known locally as Bennett's Wallaby. Other mammals include Common Wombats and Tasmanian Devils in abundance. You may also see both Eastern and Spotted Quolls, Brown and Eastern Barred Bandicoots, Bushtail and Ringtail Possums and two small macropods - the Long-nosed Potoroo and the Tasmanian Bettong. Bird life is rich with 116 species recorded.

The Park caters well for campers with several campgrounds with basic facilities and one that has showers and electric barbecues. Other accommodation can be found in nearby Launceston or Davenport. The Park has a number of walking trails to access a diversity of habitats.

Identification

The Red-necked Wallaby shows pronounced sexual dimorphism with males larger (ranging from 15-27 kg to female's 11-16 kg) and move heavily muscled in the fore-arms than females.   The Tasmanian sub-species has a thick coat and less distinct markings than the mainland sub-species. The back is grey-fawn grading to a bright rufous raiment on the neck and the rump. The undersides are white through to pale grey. Light cheek and hip stripes are visible but indistinct. The ears are black-tipped. The ears are black-tipped. Red-necked Wallabies are much larger than pademelons, potoroos and bettongs.  Eastern Grey Kangaroos do not have a cheek stripe and are grey through to chocolate with no reddish highlights. The Tasmanian sub-species (labelled as Bennett's Wallaby) is often kept in zoos in Europe and North America and may be familiar to visitors from these regions.

 

Habitat

The Red-necked Wallaby occupies a wide range of habitats but does not travel far from some form of dense cover like tall tussock grasses, shrubs and the shrubby understorey of woodland and forest. However, they range out into clear pasture and grassland from this cover to forage. Along the east coast of Australia, it is present in a broad gradient of habitat and shares this generalist characteristic with the Swamp Wallaby. The two species are largely separated by the former's preference for the ecotone between dense and open vegetation and the latter's preference for dense vegetation. In Tasmania, the Red-necked Wallaby frequently shares habitat with the smaller Tasmanian Pademelon. Both species can be abundant in forestry plantations and forage out from cover. The Red-necked Wallaby will forage further into plantations cleared and re-planted with seedlings where there is limited cover. During the day Red-necked Wallabies rest in old plantations whereas the Pademelons seek cover in denser old forest. This difference is explained by body size with the larger Red-necked Wallaby fleeing from predators and the smaller Pademelon hiding. Even so neither species will venture far into open pasture without pockets of cover.

Foraging behaviour

Predominantly grazers with some forbs (herbs), browse and the young shoots and leaves of heath-land plants in the diet. The diet of the Tasmanian sub-species studied in young pine plantations showed a strong preference for grass (74% of diet with a relative availability of 55% in the forage). The remainder of the diet was broad-leafed forbs (herbs). Damage by the wallabies to seedlings in forestry plantations has been studied. Effects are not direct in that the foraging of wallabies does not reduce seedling survival but seedling growth is impaired. Wallabies crop down grass and forbs and exposed the tree seedlings to more insect damage.

Reproductive behaviour

The reproductive biology of the Red-necked Wallaby is typical of the patterns found in the Brush Wallabies. The gestation period is about 30 d and oestrus is post-partum. Pouch life is 9 months. Breeding is aseasonal on the mainland but seasonal in the Tasmanian sub-species. The latter shows a similar pattern to that of the Tammar Wallaby with the summer solstice as the cue to birth of any diapausing blastocyst.

 

The mother-young relationship has been particularly well studied in a free-living population in north-eastern NSW. Red-necked Wallabies provided the first evidence of kinship shaping the relationships between females. Female offspring settle within their mother's home-ranges whereas males have usually dispersed elsewhere by two years of age. However, until dispersal the relationship with a son is closer than that with a daughter after weaning. Allowing either sons or daughters to remain in the mother's range reduces her chance of reproducing successfully again. Thus matrilines (lineages of female relatives) build up and the population  becomes self-regulating amongst females and fewer sons will be produced as an individual's reproductive success is suppressed (note it still has a genetic investment in its relatives) by competition from female kin.

 

The lesson we can learn from the Red-necked Wallaby and one which seems to be shared with a number of other macropod species living in the more predictable temperate and tropical climates, is that populations move to an equilibrium with their resources and self-regulate. When these populations are perturbed by lethal control measures the brakes are released from reproduction and recruitment may accelerate. Likewise if resources are improved with fertilisers and irrigation/watering, the accelerator may be depressed for a time before a new equilibrium is reached.

 

F When you see an aggregation of Red-necked Wallabies the females are likely to be relatives. If there are young-at-foot or juveniles about the see if sons or daughters are more favoured. This may be a challenge as Red-necked Wallabies are one of the 'hider' species amongst the macropods. The hider strategy is to keep the young-at-foot hidden in denser vegetation like large grass tussocks and the return regularly to them to suckle. The alternate 'follower' strategy employs by the large kangaroos and most other wallabies is for the young-at-foot to follow the mother throughout the day. However, even the latter group may 'park' their young-at-foot when going into water to drink.

Social organisation

The Red-necked Wallaby expresses a matrilineal relationship in the females but is not particularly gregarious. Thus the female kin may be well spaced out even though they share a home range. Even so mothers and their sub-adult sons and daughters and adult female relatives are frequent associates. Individuals resting in cover are usually on their own but small groups may form in open foraging habitat. These aggregations are typically much smaller than those of sympatric Whiptail Wallabies or Eastern Grey Kangaroos.

 

Individuals range over greater areas in winter than in the warmer months when grass growth is favoured. Female home ranges overlap and those of large males encompass several females. Medium-sized males tend to occupy ranges to the periphery of the main population. Females shift their home ranges closer to dense cover as their pouch young emerge consistent with their hider strategy.

 

A frequent interaction amongst males is bouts of sparring. This behaviour takes the form of play-fighting and serves to exercise fighting skills in a typically non-damaging interactions. Individuals may also learn to assess the abilities of others and potentially avoid damaging fights over resources, especially mating opportunities. Larger males may self-handicap to prolong interactions with smaller individuals; e.g. stand flat-footed rather than on their toes. This is not necessarily altruistic as they still test the skills of an emerging rival.

Further readings

Johnson CN (1986) Philopatry, reproductive success of females, and maternal investment in the red-necked wallaby. Behavioral Ecology and Sociobiology 19, 143-150.

Johnson CN (1987) Macropod studies at Wallaby Creek. V. Home range and movements of the red-necked wallaby. Australian Wildlife Research 14, 125-137.

Le Mar K, McArthur C (2005) Comparison of habitat selection by two sympatric macropods, Thylogale billardierii and Macropus rufogriseus rufogriseus, in a patchy eucalypt-forestry environment. Austral Ecology 30, 674-683.

Sprent JA, McArthur C (2002) Diet and diet selection of two species in the macropodid browser-grazer continuum: do they eat what they'should'? Australian Journal Of Zoology 50, 183-192.

Watson DM (1998) Kangaroos at play: play behaviour in the Macropodoidea. In 'Animal Play: Evolutionary, Comparative and Ecological Perspectives'. (Eds M Bekoff and JA Byers) pp. 45-98. (Cambridge University Press: Cambridge)

While GM, McArthur C (2005) Foraging in a risky environment: a comparison of Bennett's wallabies Macropus rufogriseus rufogriseus (Marsupialia: Macropodidae) and red-bellied pademelons Thylogale billiardierii (Marsupialia: Macropodidae) in open habitats. Austral Ecology 30, 756-764.