Osphranter robustus (Gould, 1841)

Russell A. Mittermeier & Don E. Wilson, 2015, Macropodidae, Handbook of the Mammals of the World – Volume 5 Monotremes and Marsupials, Barcelona: Lynx Edicions, pp. 630-735 : 728

52.

Common Wallaroo

Osphranter robustus

French: Wallarou commun / German: Bergkanguru / Spanish: Walaré comin

Other common names: Hill Kangaroo, Hill Wallaroo, Red Wallaroo, Roan Wallaroo; Eastern Wallaroo (robustus),

Barrow Island Euro/Barrow Island Wallaroo (isabellinus), Euro (erubescens), Northern Wallaroo / MVoodward'’s Wallaroo (woodward)

Taxonomy. Macropus (Petrogale) robustus Gould, 1841 ,

“ summits of the mountain ranges in the interior of New South Wales,” Australia.

Previously placed in genus Macropus , within which moved into subgenus Osphranter in 1985; in 2015 Osphranter was elevated to full genus status. Shows considerable morphological and genetic differentiation across its range. Some of the listed subspecies are highly variable, and a comprehensive genetic and morphological studyis warranted. Four subspecies recognized.

Subspecies and Distribution.

O.r.robustusGould,1841—EAustralia,excludingmostofVictoria.

O.r.erubescensSclater,1870—inlandE,C&WAustralia.

O.r.isabellinusGould1842—BarrowI,WesternAustralia.

O. r. woodward: Thomas, 1901 — NW Australia.

Descriptive notes. Head—body 58:7-108.5 cm (males) and 57.3-83.1 cm (females), tail 55.1-90.1 cm (males) and 53.4-74.9 cm (females); weight to 60 kg (males) and to 28 kg (females), for O. r. isabellinus mean weight 18-1 kg (males) and 8-6 kg (females). A large, stocky, highly sexually dimorphic wallaroo with long shaggy coat. Highly variable in coloration across range, although males typically darker than females. Generally paler ventrally and on lower limbs and tail, although digits are dark; ear margins and eyelids pale, also often pale markings on side of muzzle. O. r. robustus males are typically dark gray to black, females bluish-gray, but in north Queensland and western edge of range some individuals are reddish brown. O. r erubescens has coat shorter and ears larger; coloration grades from dark gray in east to reddish brown in central Australia and to bright brick-red in far west; females vary from gray to brown and to reddish brown, and in east some individuals have both dark gray and rufous coloration; face and ears often grayish. O. » woodwardi has shorter fur and is dull reddish brown to grayish brown, although muzzle is often more gray. O. r. isabellinus is approximately 50% smaller than adjacent mainland individuals and stockier; light reddish brown dorsally, muzzle grayish, pale and strongly contrasting ventrally. Diploid chromosome number is 16, although O. r robustus and O. r. erubescens differ in X-chromosome morphology.

Habitat. Typically occurs in a mosaic of escarpments, rocky outcrops, ridges, steeper slopes, and adjacent open foraging areas. Forages in open eucalypt forest and woodland in mesic areas, and mainly in run-on zones in arid areas, where it is strongly associated with spinifex (7riodia, Poaceae ) hummock grassland. Forages in savanna woodland in the wet=dry tropics, where it is associated with cattle grazing, soils of lower fertility, and infrequent fire. Occurs also away from rocky terrain in wide range of habitats, including Acacia (Fabaceae) shrubland, Melaleuca (Myrtaceae) woodland, monsoon woodland, and rainforest, as well as in dense shrubland along watercourses in arid areas. Can persist in habitat fragments in cropland, occupying patches of eucalypt and Allocasuarina (Casuarinaceae) woodland, mallee, and heathland.

Food and Feeding. A grazer; prefers leaves of low-fiber, high-nitrogen grasses, but will consume more chenopods in dry conditions, as well as malvaceous shrubs, forbs, reeds, sedges, and browse in small proportions. Avoids tussock grasses in spring and summer, but consumes them as available in autumn and winter. Also consumes grass sheath, stem inflorescences, and seeds, preferences for these components varying over seasons. Consumes mainly “soft” spinifex in arid areas, and is strongly attracted to new spinifex shoots after fire. Enters shallow water to eat aquatic plants at Lake Argyle, Western Australia.

Breeding. Females reach sexual maturity from 14 months and males from 18 months. Typically breeds continuously throughout year, females producing one young per pregnancy, although breeding may be reduced or cease during dry periods. In addition, northern subspecies O. r. woodwardi may breed more seasonally, with young born mostly between March and April. Females exhibit embryonic diapause and postpartum estrus, mating within a few days of giving birth. In O. rn rebustus the estrous cycle is 31-36 (mean 34) days and gestation 31-38 (mean 33) days; in O. r. erubescens estrous cycle 34-46 (mean 38) days and gestation 30-36 (mean 33) days. Young spend about eight (erubescens) to 8-5 ( robustus ) months in the pouch and are weaned at 15— 17 months. After permanent pouch emergence, young accompany the mother as a young-at-foot until well after weaning. Adult males compete intensely for access to females. Males establish dominance relationships through repetitive,ritualized bouts of display, sparring, biting, wrestling, and kicking. Males test estrous state of females by eliciting urination, nosing the stream, and exhibiting flehmen (lip-curl). Females in estrus can attract a retinue of up to six adult males, dominant male guarding the female for up to a week. Copulation is prolonged, occurring in multiple bouts averaging five minutes in length over a 70minute period.

Activity patterns. Nocturnal to crepuscular. Nocturnal activity poorly studied; daytime activity mainly confined to the two hours after sunrise and before sunset. Shelters in caves, overhangs, deep gullies, or patches of dense vegetation during day, particularly in hot, dry weather. Abandons rocky shelters after heavy rain. Moves away from shelter to more open foraging areas in evening, returning in early morning. Changes position during the day in hot weather, lying and crouching, and licking forelimbs for evaporative cooling. Some individuals apparently nevervisit water; others drink as frequently as every second day in hot, dry weather;visits are brief (average eleven minutes) and continue at least until midnight. Also drinks from soaks excavated in creek beds.

Movements, Home range and Social organization. Sedentary, with restricted movement from shelter sites to nearby foraging areas. Both sexes have quite small daily ranges, but shift their activity centers over time, so long-term range expands. Home ranges overlap extensively within and between sexes, and those of males are generally larger. Average home-range size (modified minimum convex polygon) was 46-206 ha for males and 45-102 ha for females at one semi-arid site, and was 77-401 ha at another semi-arid site where two males had elongated ranges. Average home ranges (95% Foutier transform, MAP95) at an arid site were 309 ha for males and 150 ha for females over two years, then 215-295 ha for males and 75-85 ha for females over subsequent three years. Individuals translocated to sites 6—15 km away returned to their home ranges. Dispersal is male-biased, with movements of up to 18 km reported. Essentially solitary; most often seen alone, but can occur in groups of up to 15. Average group size 1s 1-2 and is positively related to population density. Group membership is open, and both single-sex and mixed-sex groups occur. Group size and composition rarely change within a day, but frequently do so on a longer time scale. Large males and females with young-at-foot are most often alone.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Barrow Island population (isabellinus) is listed as vulnerable in Australia because of its small distribution and population size. The Common Wallaroo is widespread and locally common on Australian mainland. It is well represented in protected areas and is not currently facing any major threats. It has benefited in some areas from the clearing of forest/woodland, the establishment of improved pasture, and the provision of water for livestock. At some sites Common Wallaroos are regarded as agricultural pests and periodic culling is undertaken. They are also commercially harvested in New South Wales, Queensland, and South Australia, and are subject to local hunting by Aboriginal people in parts of central, western, and northern Australia. Most subspecies are poorly studied, and additional research into taxonomy, ecology, behavior, population genetics and demography, especially of the eastern and northern subspecies, is required.

Bibliography. Arnold, Steven & Weeldenburg (1994), Arnold, Steven, Weeldenburg & Smith (1993), Arnold, Weeldenburg & Ng (1995), Calaby & Grigg (1989), Clancy & Croft (1989, 1990, 1992, 2008), Coulson & Croft (1981), Croft (1981b, 1987 1991b), Dawson, L. & Flannery (1985), Dawson, T.J. (2012), Dawson, T.J. & Ellis (1996), DOE (2012), Ealey (1963, 1967a, 1967b, 1967c), Ealey & Main (1967), Ealey & Richardson (1960), Eldridge et al. (2014), Ellis, van Weenen, Copley et al. (2008), Groves (2005b), Harris, D.B. et al. (2014), Hayman (1989), Jackson & Groves (2015), Jarman & Taylor (1983), King & Bradshaw (2008), Kirkpatrick (1968), McAlpine et al. (1999), Poole & Merchant (1987), Ritchie, Martin, Johnson & Fox (2009), Ritchie, Martin, Krockenberger et al. (2008), Russell (1969), Russell & Richardson (1971), Short & Turner (1991), Southwell et al. (1999), Taylor (1982, 1983, 1984, 1985a, 1985b), Telfer & Bowman (2006), Telfer et al. (2008), Woinarski et al. (2014ag), Ziembicki et al. (2013).

Figures

47. Eastern Grey Kangaroo (Macropus giganteus), 48. Western Grey Kangaroo (Macropus fuliginosus), 49. Red Kangaroo (Osphranter rufus), 50. Black Wallaroo (Osphranter bernardus), 51. Antilopine Wallaroo (Osphranter antilopinus), 52. Common Wallaroo (Osphranter robustus), 53. Whip-tailed Wallaby (Notamacropus parryi), 54. Agile Wallaby (Notamacropus agilis), 55. Red-necked Wallaby (Notamacropus rufogriseus), 56. Western Brush Wallaby (Notamacropus irma), 57. Black-striped Wallaby (Notamacropus dorsalis), 58. Tammar Wallaby (Notamacropus eugenii), 59. Parma Wallaby (Notamacropus parma)

Subspecies and Distribution. O.r.robustusGould,1841—EAustralia,excludingmostofVictoria. O.r.erubescensSclater,1870—inlandE,C&WAustralia. O.r.isabellinusGould1842—BarrowI,WesternAustralia. O. r. woodward: Thomas, 1901 — NW Australia.