Macropodidae

Macropodidae is a family of marsupials that includes kangaroos, wallabies, tree-kangaroos, wallaroos, pademelons, quokkas, and several other groups. These genera are allied to the suborder Macropodiformes, containing other macropods, and are native to the Australian continent (the mainland and Tasmania), New Guinea and nearby islands. Although omnivorous kangaroos lived in the past these were not members of the family Macropodidae, modern macropods are generally herbivorous. Some are browsers, but most are grazers and are equipped with appropriately specialised teeth for cropping and grinding up fibrous plants, in particular grasses and sedges. Modern omnivorous kangaroos generally belong to a different family (for example, the Musky rat-kangaroo). In general, macropods have a broad, straight row of cutting teeth at the front of the mouth, no canine teeth, and a gap before the molars. The molars are large and, unusually, do not appear all at once but a pair at a time at the back of the mouth as the animal ages, eventually becoming worn down by the tough, abrasive grasses and falling out. Like many Macropodiformes, early kangaroos had plagiaulacoids, but these converted into normal molars in more derived species. Most species have four molars and, when the last pair is too worn to be of use, the animals starve to death. The dental formula for macropods is . Like the eutherian ruminants of the Northern Hemisphere (sheep, cattle, and so on), macropods have specialised digestive systems that use a high concentration of bacteria, protozoans, and fungi in the first chamber of a complex stomach to digest plant material. The details of organisation are quite different, but the end result is somewhat similar. The particular structure-function relationship of the Macropodidae gut and the gut microbiota allows the degradation of lignocellulosic material with a relatively low emission of methane relative to other ruminants.