The boodie (Bettongia lesueur), also known as the burrowing bettong or Lesueur's rat-kangaroo, is a small, furry, rat-like mammal native to Australia. Once common throughout the continent, it is now restricted to a few coastal islands. A member of the rat-kangaroo family (Potoroidae), it lives in burrows and is active at night when it forages for fungi, roots, and other plant matter. It is about the size of a rabbit and, like most marsupials, carries its young in a pouch.
Before European settlement, it was the most common macropod in Australia (a group that includes kangaroos, wallabies, and other Australian mammals). Competition and predation by introduced rabbits, cats, and foxes, as well as habitat loss, pressured the population. It was declared a pest in the 1900s and was wiped out by the 1960s; however, the loss of the boodie and other ground-foraging animals has degraded soil quality. Populations persisted on three west coast islands (Bernier, Dorre, and Barrow), and the boodie has been reintroduced to the mainland since the 2000s.
Taxonomy and name
The boodie belongs to the family Potoroidae, which includes the rat-kangaroos, potoroos, and other bettongs. It is one of four species in the genus Bettongia. There are three subspecies of Bettongia lesueur: B. l. graii, the extinct mainland subspecies; B. l. nova, an undescribed subspecies on Barrow and Brodie Island; and B. l. lesueur.
The word "boodie" comes from its name boodi or burdi in Noongar, an Aboriginal language spoken in southwestern Australia. The animal was first collected on an 1817 French expedition of the west coast, and was named Bettongia lesueur after Charles Lesueur, an artist and naturalist who accompanied a previous French expedition.
Paleontology
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.
Morphology
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.
Reproduction
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.