Post by Gorilla king on Apr 24, 2023 7:28:23 GMT -5
Kangaroos are four marsupials from the family Macropodidae (macropods, meaning "large foot"). In common use the term is used to describe the largest species from this family, the red kangaroo, as well as the antilopine kangaroo, eastern grey kangaroo, and western grey kangaroo.[1] Kangaroos are indigenous to Australia and New Guinea. The Australian government estimates that 42.8 million kangaroos lived within the commercial harvest areas of Australia in 2019, down from 53.2 million in 2013.[2]
As with the terms "wallaroo" and "wallaby", "kangaroo" refers to a paraphyletic grouping of species. All three terms refer to members of the same taxonomic family, Macropodidae, and are distinguished according to size. The largest species in the family are called "kangaroos" and the smallest are generally called "wallabies". The term "wallaroos" refers to species of an intermediate size.[3] There are also the tree-kangaroos, another type of macropod, which inhabit the tropical rainforests of New Guinea, far northeastern Queensland and some of the islands in the region. This kind of kangaroo lives in the upper branches of trees.[4] A general idea of the relative size of these informal terms could be:
wallabies: head and body length of 45–105 cm and tail length of 33–75 cm; the dwarf wallaby (the smallest of all known macropod species) is 46 cm long and weighs 1.6 kg;
tree-kangaroos: ranging from Lumholtz's tree-kangaroo: body and head length of 48–65 cm, tail of 60–74 cm, weight of 7.2 kg (16 lb) for males and 5.9 kg (13 lb) for females; to the grizzled tree-kangaroo: length of 75–90 cm (30 to 35 in) and weight of 8–15 kg (18–33 lb);
wallaroos: the black wallaroo (the smaller of the two species) with a tail length of 60–70 cm and weight of 19–22 kg (41.8–48.5 lb) for males and 13 kg (28.6 lb) for females;
kangaroos: a large male can be 2 m (6 ft 7 in) tall and weigh 90 kg (200 lb).
Kangaroos have large, powerful hind legs, large feet adapted for leaping, a long muscular tail for balance, and a small head. Like most marsupials, female kangaroos have a pouch called a marsupium in which joeys complete postnatal development.
Because of its grazing habits, the kangaroo has developed specialized teeth that are rare among mammals. Its incisors are able to crop grass close to the ground and its molars chop and grind the grass. Since the two sides of the lower jaw are not joined or fused together, the lower incisors are farther apart, giving the kangaroo a wider bite. The silica in grass is abrasive, so kangaroo molars are ground down and they actually move forward in the mouth before they eventually fall out, and are replaced by new teeth that grow in the back.[5] This process is known as polyphyodonty and, amongst other mammals, only occurs in elephants and manatees.
The large kangaroos have adapted much better than the smaller macropods to land clearing for pastoral agriculture and habitat changes brought to the Australian landscape by humans. Many of the smaller species are rare and endangered, while kangaroos are relatively plentiful.
The kangaroo along with the koala are symbols of Australia. A kangaroo appears on the Australian coat of arms[6] and on some of its currency,[7] and is used as a logo for some of Australia's most well-known organisations, such as Qantas,[8] and as the roundel of the Royal Australian Air Force.[9] The kangaroo is important to both Australian culture and the national image, and consequently there are numerous popular culture references.
Wild kangaroos are shot for meat, leather hides, and to protect grazing land.[10] Kangaroo meat has perceived health benefits for human consumption compared with traditional meats due to the low level of fat on kangaroos.[11]
Taxonomy and description
There are four extant species that are commonly referred to as kangaroos:
The red kangaroo (Osphranter rufus)[22] is the largest surviving marsupial anywhere in the world. It occupies the arid and semi-arid centre of the country. The highest population densities of the red kangaroo occur in the rangelands of western New South Wales. Red kangaroos are commonly mistaken as the most abundant species of kangaroo, but eastern greys actually have a larger population.[23] A large male can be 2 metres (6 ft 7 in) tall and weighs 90 kg (200 lb).[24]
The eastern grey kangaroo (Macropus giganteus)[22] is less well-known than the red (outside Australia), but the most often seen, as its range covers the fertile eastern part of the country. The range of the eastern grey kangaroo extends from the top of the Cape York Peninsula in northern Queensland down to Victoria, as well as areas of southeastern Australia and Tasmania. Population densities of eastern grey kangaroos usually peak near 100 per km2 in suitable habitats of open woodlands. Populations are more limited in areas of land clearance, such as farmland, where forest and woodland habitats are limited in size or abundance.[23]
The western grey kangaroo (Macropus fuliginosus)[22] is slightly smaller again at about 54 kg (119 lb) for a large male. It is found in the southern part of Western Australia, South Australia near the coast, and the Murray–Darling basin. The highest population densities occur in the western Riverina district of New South Wales and in the western areas of the Nullarbor Plain in Western Australia. Populations may have declined, particularly in agricultural areas. The species has a high tolerance to the plant toxin sodium fluoroacetate, which indicates a possible origin from the southwest region of Australia.[23]
The antilopine kangaroo (Osphranter antilopinus)[22] is, essentially, the far northern equivalent of the eastern grey and western grey kangaroos. It is sometimes referred to as the antilopine wallaroo, but in behaviour and habitat it is more similar to the red, eastern grey and western grey kangaroos. Like them, it is a creature of the grassy plains and woodlands, and gregarious. Its name comes from its fur, which is similar in colour and texture to that of antelopes. Characteristically, the noses of males swell behind the nostrils. This enlarges nasal passages and allows them to release more heat in hot and humid climates.[23]
In addition, there are about 50 smaller macropods closely related to the kangaroos in the family Macropodidae. Kangaroos and other macropods share a common ancestor with the Phalangeridae from the Middle Miocene.[25] This ancestor was likely arboreal and lived in the canopies of the extensive forests that covered most of Australia at that time, when the climate was much wetter, and fed on leaves and stems.[26] From the Late Miocene through the Pliocene and into the Pleistocene the climate got drier, which led to a decline of forests and expansion of grasslands. At this time, there was a radiation of macropodids characterised by enlarged body size and adaptation to the low quality grass diet with the development of foregut fermentation.[26] The most numerous early macropods, the Balbaridae and the Bulungamayinae, became extinct in the Late Miocene around 5–10 mya.[27] There is dispute over the relationships of the two groups to modern kangaroos and rat-kangaroos. Some argue that the balbarines were the ancestors of rat-kangaroos and the bulungamayines were the ancestors of kangaroos.[28] while others hold the contrary view.[29]
The middle to late bulungamayines, Ganguroo and Wanburoo lacked digit 1 of the hind foot and digits 2 and 3 were reduced and partly under the large digit 4, much like the modern kangaroo foot. This would indicate that they were bipedal. In addition, their ankle bones had an articulation that would have prohibited much lateral movements, an adaptation for bipedal hopping.[27] Species related to the modern grey kangaroos and wallaroos begin to appear in the Pliocene. The red kangaroo appears to be the most recently evolved kangaroo, with its fossil record not going back beyond the Pleistocene era, 1–2 mya.[30]
The first kangaroo to be exhibited in the Western world was an example shot by John Gore, an officer on Captain Cook's ship, HMS Endeavour, in 1770.[31][32] The animal was shot and its skin and skull transported back to England whereupon it was stuffed (by taxidermists who had never seen the animal before) and displayed to the general public as a curiosity. The first glimpse of a kangaroo for many 18th-century Britons was a painting by George Stubbs.[33]
en.m.wikipedia.org/wiki/Kangaroo
As with the terms "wallaroo" and "wallaby", "kangaroo" refers to a paraphyletic grouping of species. All three terms refer to members of the same taxonomic family, Macropodidae, and are distinguished according to size. The largest species in the family are called "kangaroos" and the smallest are generally called "wallabies". The term "wallaroos" refers to species of an intermediate size.[3] There are also the tree-kangaroos, another type of macropod, which inhabit the tropical rainforests of New Guinea, far northeastern Queensland and some of the islands in the region. This kind of kangaroo lives in the upper branches of trees.[4] A general idea of the relative size of these informal terms could be:
wallabies: head and body length of 45–105 cm and tail length of 33–75 cm; the dwarf wallaby (the smallest of all known macropod species) is 46 cm long and weighs 1.6 kg;
tree-kangaroos: ranging from Lumholtz's tree-kangaroo: body and head length of 48–65 cm, tail of 60–74 cm, weight of 7.2 kg (16 lb) for males and 5.9 kg (13 lb) for females; to the grizzled tree-kangaroo: length of 75–90 cm (30 to 35 in) and weight of 8–15 kg (18–33 lb);
wallaroos: the black wallaroo (the smaller of the two species) with a tail length of 60–70 cm and weight of 19–22 kg (41.8–48.5 lb) for males and 13 kg (28.6 lb) for females;
kangaroos: a large male can be 2 m (6 ft 7 in) tall and weigh 90 kg (200 lb).
Kangaroos have large, powerful hind legs, large feet adapted for leaping, a long muscular tail for balance, and a small head. Like most marsupials, female kangaroos have a pouch called a marsupium in which joeys complete postnatal development.
Because of its grazing habits, the kangaroo has developed specialized teeth that are rare among mammals. Its incisors are able to crop grass close to the ground and its molars chop and grind the grass. Since the two sides of the lower jaw are not joined or fused together, the lower incisors are farther apart, giving the kangaroo a wider bite. The silica in grass is abrasive, so kangaroo molars are ground down and they actually move forward in the mouth before they eventually fall out, and are replaced by new teeth that grow in the back.[5] This process is known as polyphyodonty and, amongst other mammals, only occurs in elephants and manatees.
The large kangaroos have adapted much better than the smaller macropods to land clearing for pastoral agriculture and habitat changes brought to the Australian landscape by humans. Many of the smaller species are rare and endangered, while kangaroos are relatively plentiful.
The kangaroo along with the koala are symbols of Australia. A kangaroo appears on the Australian coat of arms[6] and on some of its currency,[7] and is used as a logo for some of Australia's most well-known organisations, such as Qantas,[8] and as the roundel of the Royal Australian Air Force.[9] The kangaroo is important to both Australian culture and the national image, and consequently there are numerous popular culture references.
Wild kangaroos are shot for meat, leather hides, and to protect grazing land.[10] Kangaroo meat has perceived health benefits for human consumption compared with traditional meats due to the low level of fat on kangaroos.[11]
Taxonomy and description
There are four extant species that are commonly referred to as kangaroos:
The red kangaroo (Osphranter rufus)[22] is the largest surviving marsupial anywhere in the world. It occupies the arid and semi-arid centre of the country. The highest population densities of the red kangaroo occur in the rangelands of western New South Wales. Red kangaroos are commonly mistaken as the most abundant species of kangaroo, but eastern greys actually have a larger population.[23] A large male can be 2 metres (6 ft 7 in) tall and weighs 90 kg (200 lb).[24]
The eastern grey kangaroo (Macropus giganteus)[22] is less well-known than the red (outside Australia), but the most often seen, as its range covers the fertile eastern part of the country. The range of the eastern grey kangaroo extends from the top of the Cape York Peninsula in northern Queensland down to Victoria, as well as areas of southeastern Australia and Tasmania. Population densities of eastern grey kangaroos usually peak near 100 per km2 in suitable habitats of open woodlands. Populations are more limited in areas of land clearance, such as farmland, where forest and woodland habitats are limited in size or abundance.[23]
The western grey kangaroo (Macropus fuliginosus)[22] is slightly smaller again at about 54 kg (119 lb) for a large male. It is found in the southern part of Western Australia, South Australia near the coast, and the Murray–Darling basin. The highest population densities occur in the western Riverina district of New South Wales and in the western areas of the Nullarbor Plain in Western Australia. Populations may have declined, particularly in agricultural areas. The species has a high tolerance to the plant toxin sodium fluoroacetate, which indicates a possible origin from the southwest region of Australia.[23]
The antilopine kangaroo (Osphranter antilopinus)[22] is, essentially, the far northern equivalent of the eastern grey and western grey kangaroos. It is sometimes referred to as the antilopine wallaroo, but in behaviour and habitat it is more similar to the red, eastern grey and western grey kangaroos. Like them, it is a creature of the grassy plains and woodlands, and gregarious. Its name comes from its fur, which is similar in colour and texture to that of antelopes. Characteristically, the noses of males swell behind the nostrils. This enlarges nasal passages and allows them to release more heat in hot and humid climates.[23]
In addition, there are about 50 smaller macropods closely related to the kangaroos in the family Macropodidae. Kangaroos and other macropods share a common ancestor with the Phalangeridae from the Middle Miocene.[25] This ancestor was likely arboreal and lived in the canopies of the extensive forests that covered most of Australia at that time, when the climate was much wetter, and fed on leaves and stems.[26] From the Late Miocene through the Pliocene and into the Pleistocene the climate got drier, which led to a decline of forests and expansion of grasslands. At this time, there was a radiation of macropodids characterised by enlarged body size and adaptation to the low quality grass diet with the development of foregut fermentation.[26] The most numerous early macropods, the Balbaridae and the Bulungamayinae, became extinct in the Late Miocene around 5–10 mya.[27] There is dispute over the relationships of the two groups to modern kangaroos and rat-kangaroos. Some argue that the balbarines were the ancestors of rat-kangaroos and the bulungamayines were the ancestors of kangaroos.[28] while others hold the contrary view.[29]
The middle to late bulungamayines, Ganguroo and Wanburoo lacked digit 1 of the hind foot and digits 2 and 3 were reduced and partly under the large digit 4, much like the modern kangaroo foot. This would indicate that they were bipedal. In addition, their ankle bones had an articulation that would have prohibited much lateral movements, an adaptation for bipedal hopping.[27] Species related to the modern grey kangaroos and wallaroos begin to appear in the Pliocene. The red kangaroo appears to be the most recently evolved kangaroo, with its fossil record not going back beyond the Pleistocene era, 1–2 mya.[30]
The first kangaroo to be exhibited in the Western world was an example shot by John Gore, an officer on Captain Cook's ship, HMS Endeavour, in 1770.[31][32] The animal was shot and its skin and skull transported back to England whereupon it was stuffed (by taxidermists who had never seen the animal before) and displayed to the general public as a curiosity. The first glimpse of a kangaroo for many 18th-century Britons was a painting by George Stubbs.[33]
en.m.wikipedia.org/wiki/Kangaroo