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
The Pademelons are small, compact, short-tailed wallabies that typically inhabit wet sclerophyll and rainforests from Tasmania to New Guinea. The genus is equally diverse in New Guinea (4 species) and Australia (3 species) with one of the latter, the Red-legged Pademelon (T. stigmatica), in both regions. The Pademelons occupy an interesting taxonomic position and may have been the ancestors of both Tree-kangaroos and Rock-wallabies a few million years ago. Given the absence of Rock-wallabies from New Guinea but presence of Pademelons in both Australia and New Guinea, Tree-kangaroos likely evolved first, probably in New Guinea, and two species entered the far north through Cape York. Rock-wallabies evolved later in Australia, probably on the east coast where Pademelons are found, and when no suitable habitat breached the Torres Strait or Bass Strait given their absence from Tasmania.
Reddish coloured fur is something of a theme with red-bellied, red-necked and red-legged in the species common names. They emerge from forest cover at night to eat succulent grasses and take some browse. They have remained common over much of their geographic range but the Tasmanian Pademelon was once found in south-eastern South Australia and Victoria. Dense thickets of vegetation are required for shelter and so habitat fragmentation and clearing reduce the viability of populations.
Species
Red-necked Pademelon
Thylogale thetis ('Thetis's [Bougainville's ship] pouched-weasel')
Best place to see
Barrington Tops National Park, New South Wales
Barrington Tops National Park is 263 km and about 4.5 hours drive from Sydney. The Park is formed from an ancient volcano and rises to over 1500 m above sea level. It is part of the Gondwana Rainforests of Australia World Heritage Area. Thus it contains sub-tropical rainforest but the plateau is sub-alpine forest and snow is common in winter. Most of the Park is wilderness and there are extensive walking trails. The Park is divided into a number of sections and has extensive visitor facilities. The two main fully serviced campgrounds are at the Gloucester River and Polblue. There are a number of other bush camping sites in the Mt Barrington section and Devils hole and day visitor facilities in each section. There are also private accommodations near the Park boundaries.
The Park has a rich macropod fauna that also includes the Long-nosed Potoroo, Parma Wallaby, Red-necked Wallaby, Swamp Wallaby, Brush-tailed Rock Wallaby, Eastern Grey Kangaroo.
Identification
Males to 9.1 kg (average 7.0 kg) and females to 4.3 kg (average 3.8 kg). The Red-necked Pademelon has moderate build between the slender Red-legged Pademelon and the robust Tasmanian Pademelon. The medium length fur is thick and soft; the underfur is long and grey. The overall colour is a grizzled grey, but the species derives its common name from the red-brown on the shoulders. The head is a uniform grizzled grey colour and lacks a dark dorsal stripe. The ears are long and their backs are grey with brown or black edge. Some individuals express a faint white hip stripe but it is usually lacking. The undersides (the chin, chest and abdomen) are white, and well-defined from the upper body colour. The arms and legs vary from grey to red, and the hands and feet are pale brown. The base of the tail is grey, like the back, but the rest is brown above and white below. The tail is held like a stiff rod when hopping unlike the Parma Wallaby that can be found in the same habitat.
Habitat
The Red-necked Pademelon prefers the ecotone between forest and grassy patches or pasture. The rest and forage in the forest and then follow well-defined pads out to adjacent grasslands to forage mainly at night. They rarely emerge more than about 100 m from the forest edge but may penetrate the forest to 500 m or more. In the northern part of its range it is sympatric with Red-legged Pademelons.
Foraging behaviour
The diet of the Red-necked Pademelon is many short grasses and herbs but they will browse from some shrubs. They can be active throughout the day and night with a deeper rest period around midday through to mid-afternoon. In the day they forage in the shelter of the forest and emerge onto open habitat out from the forest edge at nightfall returning to shelter by dawn. In cooler weather they may bask in open patches in the forest.
Reproductive behaviour
The reproductive physiology of the Red-necked Pademelon is less well studied than the other Pademelons. Breeding is continuous with birth peaks in the autumn and spring. The pouch life is around 6 months. The length of gestation is not currently known and there is a suggestion that oestrus may not be post-partum oestrus with an interval up to 7 days between birth and the next fertilisation. Embryonic diapause has not yet been determined. Young are weaned at about 9 months. Females mature at 12 months in captivity but more like 17 months in the wild.
The species is sexually dimorphic with males larger and more muscular in the forelimbs and chest than females. Males court females with a soft clucking vocalisation typical of many macropods. In captivity, females given a choice between small, medium and large males chose the latter as the approached and entered oestrus. They also associated strongly with males when in oestrus even though they did not have physical contact. Thus in aggregations in the wild, females may exercise mate choice and be most receptive to large males and make seek them out when in oestrus.
In aggressive encounters within and between the sexes a guttural growl vocalisation is uttered. Individuals are usually solitary but may aggregate in relatively large numbers on nocturnal foraging areas where social interactions may occur.
Social organisation
Home ranges are relatively large at 5-30 ha and include distinct daytime areas in the forest and smaller night-time areas on pasture at the forest edge. The Pademelons stay in or close to cover at all times and rarely venture more than 100 m from the forest edge. They are hunted by dingoes and foxes. Individuals are usually solitary in the forest but may aggregate in loose intermingling groups of 10 or more at night when in open habitat. Group size increases with distance from the forest edge and thereby individual pademelons do not increase their vigilance. Vigilance and foraging are negatively correlated and vigilance increases as a function of perceived risk; i.e. greater in small groups and longer distances from cover. Alarmed individuals foot thump and groups scatter back into the forest. Red-necked Pademelons when presented with a synthetic dog urine spent time inspecting the site rather than avoiding it. This contrasted to Parma Wallabies that live within the forest and who avoided sites with the urine analogue. Thus Pademelons may assess risk by the decay in odours from potential predators on venturing into open habitat whereas Parma Wallabies avoid any risk and forage elsewhere in the forest.
Further readings
Blumstein, D.T., Daniel, J.C., Schnell, M.R., Ardron, J.G., Evans, C.S., 2002. Antipredator behaviour of red-necked pademelons: a factor contributing to species survival? Animal Conservation 5, 325-331.
Johnson, K.A., 1980. Spatial and temporal use of habitat by the red-necked pademelon, Thylogale thetis (Marsupialia: Macropodidae). Australian Wildlife Research 7, 157-166.
Radford, S.L., Croft, D.B., Moss, G.L., 1997. Mate choice in female Red-necked Pademelons, Thylogale thetis (Marsupialia: Macropodoidea). Ethology 104, 217-231.
Ramp, D., Russell, B.G., Croft, D.B., 2005. Predator scent induces differing responses in two sympatric macropodids. Australian Journal of Zoology 53, 73-78.
Wahungu, G.M., Catterall, C.P., Olsen, M.F., 2001. Predator avoidance, feeding and habitat use in the red-necked pademelon, Thylogale thetis, at rainforest edges. Australian Journal of Zoology 49, 45-48.