Bennetts Wallaby - Macropus rufogriseus rufogriseus
The Bennetts Wallaby is a subspecies of the Red-necked Wallaby found on the Australian mainland. It is also sometimes known in Tasmania as the Brush Wallaby or Kangaroo (not to be confused with the Forester Kangaroo). It usually grows 70-90 cm tall, but may reach up to 1.5 metres, and averages 14kg (females) to 19kg (males). Fur is grizzled in appearance, with grey to red hairs being tipped with white, and a white underbelly. The paws, the tip of the hindleg, and muzzle are black. The Tasmanian form is a little darker with longer and denser fur than its mainland cousin. It is slightly smaller in overall size, but heavier on average.
Bennetts Wallabies are mostly nocturnal, but may also be seen grazing in the late afternoon. They are fleet of foot and very agile, even over rocky, steep or timber-strewn terrain.
The Bennetts Wallaby is common over much of Tasmania, including the larger Bass Strait Islands and the fringes of our cities. It also occurs on Maria Island, where it was introduced in the 1970s. Their range extends into the colder parts of Tasmania, including regions prone to snow. Until the second half of last century they mainly resided in the forests, but as much forested area has disappeared, they have adapted to a changed environment created by agricultural clearning, utilising what naitve bushland there is for refuge/cover during the daylight hours.
They live in eucalypt forests, in open forested areas and in tall coastal heath. They will hide in dense scrub, but can also be found in open areas during the day resting and sunning themselves. The common mosaic pattern of agriculture, with pastures, fields and plantations intertwined with patches of bushland, has suited the Bennetts Wallaby, giving them access to shelter by day, and nearby pastures and fields to graze by night. They show a preference for resting during the day in older plantations, where available. Plantations have minimal undergrowth but low branches and windrows. It is thought that wallabies prefer these plantations because, while providing shelter, these areas also enable good visibility to detect predators and be able to flee.
Bennetts Wallabies are predominantly grazing animals, eating mainly grasses and herbs. Studies have shown that grasses make up approximately 74% of the total diet of Bennetts Wallabies, and broad-leafed plants make up 17% of the diet, although this balance would depend on the available food at the time. The wallaby also includes the growing tips of shrubs and young trees in its diet.
Wallabies are treated as a pest when they browse plantations, and have shown preferences for browsing young plantations. They travel reasonable distances to suitable grazing land, often making well-formed “runways” beneath vegetation and fences.
When sheltering during the day, the wallabies usually rest on their own, females with perhaps a joey at foot. Occasionally they are accompanied by an adult male. They emerge from their individual sheltering spots to graze in groups.
Home ranges vary widely, with the availability of food. Studies in Tasmania have shown ranges from 30 hectares to 130 hectares. Males have larger home ranges than females, possibly twice as large.
Bennetts Wallabies keep a lookout for predators, tending to be less vigilant as the size of their group increases. They also tend to be more vigilant in keeping watch when it is windy, as the wind masks the sound and scent of predators. When disturbed they hop off at speed in different directions, a tactic to confuse predators.
They tend to graze at some distance from shelter, which may also hide potential predators, relying on their speed to escape. The main predators, since the demise of the Tasmania Tiger, are wild dogs and humans.
On the mainland this species gives birth in all months, in Tasmania the subspecies has a well-defined breeding season. Births occur from January to July, with most young born in February and March.
Although the gestation period is 30 days, in Tasmania females with no pouch young that mate at the end of the breeding season, do not give birth until the following breeding season, up to 8 months later. After the permanent emergence of the large joey a new offspring is born 16-29 days later. In addition the mother wallaby can conceive at a ‘post-partum’ mating with this fertilised embryo remaining suspended within her uterus until the newest joey has left the pouch. Nature is wonderous!
The joey lives in the pouch for around 280 days and continues to be suckled by the mother until it is 12-17 months old.
As with Tasmanian Pademelons, the joey that has emerged from the pouch continues to suckle on a different nipple to that of the new born young, each being supplied with milk that has a different fat and protein level appropriate for the age of each joey.
Bennetts Wallabies are partly protected wildlife. They are hunted during open seasons, their skins and meat sold commercially, and killed by forestry companies and farmers with ‘crop protection permits’. See the Issues Sheets No. 5, 6 & 7.
Shooting is affecting the age and genetic structure of wallaby populations. The number of males in the population is reduced by the selective killing of larger (and older) animals, and the average age of the population is significantly reduced. The age at which the wallabies breed is also younger in areas where there is continued shooting pressure. This suggests that populations are under stress, and are responding by increasing their reproduction rate to maintain their population. Bennetts Wallabies are vulnerable to increases in hunting pressure.
Droughts significantly decrease breeding success in Bennetts Wallabies (and pademelons to a lesser extent). They are therefore susceptible to the changes in rainfall attributed to climate change.
Wallabies are also susceptible to roadkill, being one of the most common species killed on Tasmanian Roads.
Photos: © Karen Bevis (top) & Megan Earl (bottom)
Against Animal Cruelty Tasmania, Tasmanian Conservation Trust & Voiceless © 2012