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.[3] Most species have four molars and, when the last pair is too worn to be of use, the animals starve to death.[4] The dental formula for macropods is 3.0–1.2.41.000.2.4.
Like the eutherianruminants 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. These low emissions are partly explained by the anatomical differences between the macropodid digestive system and that of ruminants, resulting in shorter retention times of particulate digesta within the foregut. This fact might prevent the establishment of methanogenic archaea, which has been found in low levels in tammar wallabies (Notamacropus eugenii) and eastern grey kangaroo (M. giganteus). Metagenomic analysis revealed that the foregut of tammar wallabies mainly contains bacteria belonging to the phyla Bacillota, Bacteroidota, and Pseudomonadota. Among Pseudomonadota populations of the Succinivibrionaceae family are overrepresented and may contribute to low methane emissions.[5]
Macropods vary in size considerably, but most have very large hind legs and long, powerfully muscled tails. The term macropod comes from the Greek for "large foot" and is appropriate: most have very long, narrow hind feet with a distinctive arrangement of toes. The fourth toe is very large and strong, the fifth toe moderately so; the second and third are fused; and the first toe is usually missing. Their short front legs have five separate digits. Some macropods have seven carpal bones instead of the usual eight in mammals.[6] All have relatively small heads and most have large ears, except for tree-kangaroos, which must move quickly between closely spaced branches. The young are born very small and the pouch opens forward.
The unusual development of the hind legs is optimised for economical long-distance travel at fairly high speed. The greatly elongated feet provide enormous leverage for the strong legs, but the famous kangaroo hop has more: kangaroos and wallabies have a unique ability to store elastic strain energy in their tendons. In consequence, most of the energy required for each hop is provided "free" by the spring action of the tendons (rather than by muscular effort). The main limitation on a macropod's ability to leap is not the strength of the muscles in the hindquarters, it is the ability of the joints and tendons to withstand the strain of hopping.
Furthermore, the act of hopping in kangaroos and wallabies is associated with their breathing process. The movement of their feet off the ground helps to expel air from their lungs, while bringing their feet forward for landing replenishes their lungs with air, resulting in greater energy efficiency. Studies conducted on these animals have shown that hopping at faster speeds requires only a minimal increase in effort beyond the energy required to hop in general, which is significantly less than what would be required in other animals like horses, dogs, or humans. Additionally, it has been observed that carrying extra weight requires little additional energy, which is particularly important for female kangaroos and wallabies carrying heavy pouch young.[citation needed]
The ability of larger macropods to survive on poor-quality, low-energy feed, and to travel long distances at high speed without great energy expenditure (to reach fresh food supplies or waterholes, and to escape predators) has been crucial to their evolutionary success on a continent that, because of poor soil fertility and low, unpredictable average rainfall, offers only very limited primary plant productivity.
Most macropod species have a polygynous mating system[7] and produce a mating plug after copulation.[8][9]Gestation in macropods lasts about a month, being slightly longer in the largest species. Typically, only a single young is born, weighing less than 1g (0.035oz) at birth. They soon attach themselves to one of four teats inside the mother's pouch. The young leave the pouch after five to 11 months, and are weaned after a further two to six months. Macropods reach sexual maturity at one to three years of age, depending on the species.[10]
The evolutionary ancestors of marsupials split from placental mammals during the Jurassic period about 160 million years ago (Mya).[11] The earliest known fossil macropod dates back about 11.61 to 28.4 Mya, either in the Miocene or Late Oligocene, and was uncovered in South Australia. Unfortunately, the fossil could not be identified any further than the family. A Queensland fossil of a species similar to Hadronomas has been dated at around 5.33 to 11.61 Mya, falling in the Late Miocene or Early Pliocene. The earliest completely identifiable fossils are from around 5.33 Mya.[12]
Tree-kangaroos have smaller ears for easier maneuvering between tree branches, and a much longer tail.A red kangaroo showing pentapedal locomotion while grazing: the forelimbs and tail take the animal's weight while the hind legs are brought forward.A pademelon has typical macropod legs, although they are obscured by fur in this image.A pademelon eating a slice of sweet potato: Although usually grazing directly from the ground with their mouth, macropods may also use their front paws to assist in grazing.A "forester kangaroo" hopping over a puddle
The listing for extant species is based on The Third edition of Wilson & Reeder's Mammal Species of the World (2005), except where the Mammal Diversity Database and IUCN agree on a change. The two living subfamilies in the family Macropodidae are the Lagostrophinae, represented by a single species, the banded hare-wallaby, and the remainder, which make up the subfamily Macropodinae (67 species).
A wallaby is a small or middle-sized macropod native to Australia and New Guinea, with introduced populations in New Zealand, Hawaii, the United Kingdom and other countries. They belong to the same taxonomic family as kangaroos and sometimes the same genus, but kangaroos are specifically categorised into the four largest species of the family. The term "wallaby" is an informal designation generally used for any macropod that is smaller than a kangaroo or a wallaroo that has not been designated otherwise.
Tree-kangaroos are marsupials of the genus Dendrolagus, adapted for arboreal locomotion. They inhabit the tropical rainforests of New Guinea and far northeastern Queensland, along with some of the islands in the region. All tree-kangaroos are considered threatened due to hunting and habitat destruction. They are the only true arboreal macropods.
The parma wallaby is a small marsupial macropod mammal native to forests and densely-vegetated areas of northeastern New South Wales, Australia, close to the border with Queensland. There is also an introduced population found in and around Rodney District, just north of Auckland, New Zealand. About the size of a stout cat, it lives mainly under thick plant cover, and is only active at night when it emerges to feed on grasses and small plants. It is the smallest of the wallabies and carries its young in a pouch, as with other marsupials. Shy and elusive, it was believed extinct until its rediscovery in the 1960s.
The tammar wallaby, 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 wallaby 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 extirpated. Skull variations differentiate between tammar wallabies from Western Australia, Kangaroo Island, and mainland South Australia, making them distinct population groups.
Macropus is a marsupial genus in the family Macropodidae. It has two extant species of large terrestrial kangaroos. The term is derived from the Ancient Greek μάκρος, makros "long" and πους, pous "foot". Thirteen known extinct species are recognised. The type species is the eastern grey kangaroo.
The Macropodiformes, also known as macropods, are one of the three suborders of the large marsupial order Diprotodontia. They may in fact be nested within one of the suborders, Phalangeriformes. Kangaroos, wallabies and allies, bettongs, potoroos and rat kangaroos are all members of this suborder.
The western brush wallaby, also known as the black-gloved wallaby, is a species of wallaby found in the southwestern coastal region of Western Australia. The wallaby's main threat is predation by the introduced red fox. The IUCN lists the western brush wallaby as Least Concern, as it remains fairly widespread and the population is believed to be stable or increasing, as a result of red fox control programs.
Macropodinae is a subfamily of marsupials in the family Macropodidae, which includes the kangaroos, wallabies, and related species. The subfamily includes about ten genera and at least 51 species. It includes all living members of the Macropodidae except for the banded hare-wallaby, the only surviving member of the subfamily Lagostrophinae.
Osphranter is a genus of large marsupials in the family Macropodidae, commonly known as kangaroos and wallaroos. It contains the largest extant marsupial, the red kangaroo.
Notamacropus is a genus of small marsupials in the family Macropodidae, commonly known as wallabies. The term is derived from the Latin nota "stripe" and macropus "kangaroo", referencing the distinct facial stripe of many extant genus members and their phylogenetic relationship to other kangaroos.
↑ Clode, D (2006). Continent of Curiosities: A Journey Through Australian Natural History. Melbourne: Cambridge University Press. pp.25–8. ISBN978-0-521-86620-0.
↑ Gurovich, Y.; Beck, R. (2009). "The phylogenetic affinities of the enigmatic mammalian clade Gondwanatheria". Journal of Mammalian Evolution. 16 (1): 25–49. doi:10.1007/s10914-008-9097-3. S2CID42799370.
↑ The Paleobiology Database (2011). "Macropodidae (kangaroo)". The Paleobiology Database. Majura Park, ACT, Australia: Australian Research Council. Retrieved 11 July 2011.
↑ Haaramo, M (20 December 2004). "Macropodidae: kenguroos". Mikko's Phylogeny Archive. Archived from the original on 31 March 2007. Retrieved 15 March 2007.
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