Bettongia lesueur

The boodie (Bettongia lesueur), also known as the burrowing bettong, is a small marsupial. Its population is an example of the effects of introduced animals on Australian fauna and ecosystems. Once the most common macropodiform mammal on the whole continent, the boodie now only lives on off-lying islands and in a newly introduced population on the mainland at Shark Bay. This animal, first collected during an 1817 French expedition of the west coast, was named after Charles Lesueur, an artist and naturalist who accompanied a previous French expedition. B. lesueur is known by many common names, including the tungoo, Lesueur’s rat-kangaroo, and the short-nosed rat-kangaroo. The boodie belongs to the family Potoroidae, which includes the rat-kangaroos, potoroos, and other bettongs. Four species make up the genus Bettongia. Also, three subspecies of Bettongia lesueur exist: B. l. graii, the extinct mainland subspecies; B. l. nova, an undescribed species on Barrow and Brodie Island; and B. l. lesueur. The common name boodie is adopted from the Nyungar language, burdi being a name used in the southwest of Australia. In the late Oligocene, fossils of paleopotoroines and potoroines (potoroid ancestors) appeared. During the Oligocene, ice buildup on Antarctica resulted in less rainfall on Australia. Rainforests declined, replaced by more arid-tolerant leathery leaf woodlands and reed swamps. This climate shift may have favored a radiation of terrestrial marsupials, including potoroid ancestors. Fossils of the family Potoroidae appear from the mid-Miocene to Recent sediments. Subfossil records of the burrowing bettong have been found in West Victoria, western New South Wales, and South Australia. The boodie is a small, rat-like marsupial with short, rounded ears and a lightly haired, thick tail. This animal has a pointed rostrum and beady black eyes, hind limbs longer than the forelimbs, and large hind feet. This bettong is yellow-gray above and light gray below. Its short, dense fur feels soft and woolly. The animal bears a faint hip stripe and a distinctive white tail tip. This tail is weakly prehensile and used to carry nest material. About the size of a wild rabbit, this little marsupial weighs an average of 1.5 kg. Head and body length is an average of 40 cm. Little to no sexual dimorphism seems to exist. However, morphology varies among subspecies and between islands. In general, a potoroid skull can be separated from a macropodid skull by the presence of well-developed upper canines and large plagiaulacoid (bladelike) premolars. Also unlike macropodids, the squamosal bone widely contacts the frontal. B. lesueur skulls are short and broad with large palatal vacuities, inflated auditory bullae, and short, broad nasals. The mandible is relatively short and deep compared to other relatives. The dental formula for all the modern potoroines is I 3/1 C 1/0 PM 1/1 M 4/4. Molars are bunodont and quadrate, and the premolars have 9-11 fine, vertical ridges. Young bettongs have two molars which are replaced by one adult premolar; this event is a good indication of maturity. The postcranial skeleton of all potoroids has seven cervical, 13 thoracic, six lumbar, two sacral, and 22 caudal vertebrae, with 13 pairs of ribs. If conditions are good, the boodie seems to mate throughout the year, probably using a polygynous mating system. Males do not seem to have dominance hierarchies; rather, they defend females against other males. Some females seem to establish associations with other females; whether these contribute to increased reproductive success is unknown. Gestation lasts 21 days, with only one young per litter. Like other marsupial newborns, the newborn is altricial. About four months elapse until weaning. After young leave the pouch, they take six to seven months to mature sexually. Females mate the day after giving birth, and the fertilized egg arrests development until the young is weaned. This is an example of facultative embryonic diapause. In captivity, females are able to bear three young per year. The boodie once lived in a range of dry subtropical and tropical habitats, from open eucalyptus and acacia woodlands to arid spinifex grasslands. In its current range on the islands, it seems to prefer open Triodia (spinifex) and dune habitats, but will burrow anywhere except places with rocky substrate. The burrowing bettong eats a variety of foods, such as seeds, fruits, flowers, tubers, roots, succulent leaves, grasses, fungi, termites, and marine refuse. It will also raid vegetable gardens. Current populations fluctuate, building up during the years with average or good rainfall and crashing during drought years. These marsupials are known to live at least three years in the wild.