Tammar wallaby

The tammar wallaby (Macropus eugenii), also known as the dama wallaby or darma wallaby, is a small macropod native to South and Western Australia. Though its geographical range has been severely reduced since European colonisation, the tammar remains common within its reduced range and is listed as 'Least Concern' by the International Union for Conservation of Nature (IUCN). It has been introduced to New Zealand and reintroduced to some areas of Australia where it had been previously eradicated. Skull differences distinguish tammars from Western Australia, Kangaroo Island and mainland South Australia, making them distinct population groups or possibly different subspecies. The tammar is among the smallest of the wallabies in the genus Macropus. Its coat colour is largely grey. The tammar has several notable adaptations, including the ability to retain energy while hopping, colour vision and the ability to drink seawater. A nocturnal species, it spends nighttime in grassland habitat and daytime in shrubland. It is also very gregarious and has a seasonal, promiscuous mating pattern. A female tammar can nurse a joey in her pouch while keeping an embryo in her uterus. The tammar is a model species for research on marsupials, and on mammals in general. It is one of many organisms to have had its genome sequenced. The tammar wallaby was seen in the Houtman Abrolhos off Western Australia by survivors of the 1628 Batavia shipwreck, and recorded by François Pelsaert in his 1629 Ongeluckige Voyagie.:53 It was first described in 1817 by the French naturalist Anselme Gaëtan Desmarest, who gave it the name eugenii based on where it was found; an island he knew as Ile Eugene in the Nuyts Archipelago off South Australia which is now known as St Peter Island. The island's French name was given in honour of Eugene Hamelin, commander of the ship Naturaliste;:333 whose name is now the specific name of the tammar. The common name of the animal is derived from the thickets of the shrub locally known as tamma (Allocasuarina campestris) that sheltered it in Western Australia. The tammar is classified together with the kangaroos, wallaroos and several species of wallaby in the genus Macropus, and in the subgenus Notamacropus with the other wallabies, all of which have a facial stripe. Fossil evidence of the tammar wallaby exists from the late Pleistocene era—remains were found in the Naracoorte Caves. The mainland and island dwelling tammars split from each other 7,000–15,000 years ago,:332 while the South Australian and Western Australian animals diverged around 50,000 years ago. The tammar wallabies on Flinders Island had greyer coats and thinner heads than the Kangaroo Island tammars, which are larger than the East and West Wallabi Islands animals. The island tammars were once thought to be a separate species from the mainland population.:333 A 1991 examination of tammar skulls from different parts of the species' range found that populations can be divided into three distinct groups: one group made of populations from mainland Western Australia, East and West Wallabi Islands, Garden Island and Middle Island; a second group comprising populations from Flinders Island, 19th century mainland Southern Australia and New Zealand; and a third group consisting solely of the Kangaroo Island population. The Western Australia Department of Environment and Conservation listed these populations as subspecies; M. e. derbianus, M. e. eugenii and M. e. decres respectively. One of the smallest wallaby species in the genus Macropus, the tammar wallaby features a small head and large ears with a long tail, thick at the base. It has dark grey-brown upperparts with paler grey highlights, rufous on the sides of the body and limbs, particularly in males, and pale grey-buff underparts. The tammar wallaby exhibits significant sexual dimorphism, with the maximum recorded weight in males being 9.1 kg (20 lb) and maximum recorded weight in females is 6.9 kg (15 lb). The body length is 59 to 68 cm (23–27 in) in males and 52 to 63 cm (20–25 in) in females. Both males and females are about 45 cm (18 in) in height. The tails of males range from 34 to 45 cm (13–18 in) and those of females from 33 to 44 cm (13–17 in). As with most macropods, the tammar wallaby moves around by hopping. This species has a hopping frequency of 3.5 strides per second, with a stride length of 0.8 to 2.4 m (2.6–7.9 ft). When hopping, proximal muscles at the knee and hip joints generate most of the power for each leap, which are delivered by multi-joint muscles at the ankle. As it lands, the energy of the jump is converted into strain energy made when its leg tendons are stretched. As it leaps back off the ground, the tammar can recover much of this energy for reuse though elastic recoil.