Kangaroo 2 Download

[Adimar Nigerson]

Kangaroosare 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:

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, despite to a common misconception to the contrary.[6][7]

The kangaroo along with the koala are symbols of Australia. A kangaroo appears on the Australian coat of arms[8] and on some of its currency,[9] and is used as a logo for some of Australia's most well-known organisations, such as Qantas,[10] and as the roundel of the Royal Australian Air Force.[11] 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.[12] Kangaroo meat has perceived health benefits for human consumption compared with traditional meats due to the low level of fat on kangaroos.[13]

The word kangaroo derives from the Guugu Yimithirr word gangurru, referring to eastern grey kangaroos.[14][15] The name was first recorded as "kanguru" on 12 July 1770 in an entry in the diary of Sir Joseph Banks; this occurred at the site of modern Cooktown, on the banks of the Endeavour River, where HMS Endeavour under the command of Lieutenant James Cook was beached for almost seven weeks to repair damage sustained on the Great Barrier Reef.[16] Cook first referred to kangaroos in his diary entry of 4 August. Guugu Yimithirr is the language of the people of the area.

A common myth about the kangaroo's English name is that it was a Guugu Yimithirr phrase for "I don't know" or "I don't understand".[17] According to this legend, Cook and Banks were exploring the area when they happened upon the animal. They asked a nearby local what the creatures were called. The local responded "kangaroo", said to mean "I don't know/understand", which Cook then took to be the name of the creature.[18] Anthropologist Walter Roth was trying to correct this legend as far back as in 1898, but few took note until 1972 when linguist John B. Haviland in his research with the Guugu Yimithirr people was able to confirm that gangurru referred to a rare large dark-coloured species of kangaroo.[18][19] However, when Phillip Parker King visited the Endeavour River region in 1819 and 1820, he maintained that the local word was not kangaroo but menuah perhaps referring to a different species of macropod.[20] There are similar, more credible stories of naming confusion, such as with the Yucatn Peninsula.[18]

Kangaroos are often colloquially referred to as "roos".[21] Male kangaroos are called bucks, boomers, jacks, or old men; females are does, flyers, or jills; and the young ones are joeys.[22] The collective noun for a group of kangaroos is a mob, court, or troupe.[23]

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.[33][34] 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.[35]

Kangaroos and wallabies belong to the same taxonomic family (Macropodidae) and often the same genera, 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.[3]

Kangaroos have single-chambered stomachs quite unlike those of cattle and sheep, which have four compartments.[39][40] They sometimes regurgitate the vegetation they have eaten, chew it as cud, and then swallow it again for final digestion. However, this is a different, more strenuous, activity than it is in ruminants, and does not take place as frequently.[41]

Different species of kangaroos have different diets, although all are strict herbivores. The eastern grey kangaroo is predominantly a grazer, and eats a wide variety of grasses, whereas some other species such as the red kangaroo include significant amounts of shrubs in their diets. Smaller species of kangaroos also consume hypogeal fungi. Many species are nocturnal,[42] and crepuscular,[43][44] usually spending the hot days resting in shade, and the cool evenings, nights and mornings moving about and feeding.

Despite having herbivorous diets similar to ruminants such as cattle, which release large quantities of digestive methane through exhaling and eructation (burping), kangaroos release virtually none. The hydrogen byproduct of fermentation is instead converted into acetate, which is then used to provide further energy. Scientists are interested in the possibility of transferring the bacteria responsible for this process from kangaroos to cattle, since the greenhouse gas effect of methane is 23 times greater than carbon dioxide per molecule.[45]

Groups of kangaroos are called mobs, courts or troupes, which usually have 10 or more kangaroos in them. Living in mobs can provide protection for some of the weaker members of the group.[23] The size and stability of mobs vary between geographic regions,[28][46][47] with eastern Australia having larger and more stable aggregations than in arid areas farther west.[28] Larger aggregations display high amounts of interactions and complex social structures, comparable to that of ungulates.[28] One common behavior is nose touching and sniffing, which mostly occurs when an individual joins a group.[32] The kangaroo performing the sniffing gains much information from smell cues. This behavior enforces social cohesion without consequent aggression. During mutual sniffing, if one kangaroo is smaller, it will hold its body closer to the ground and its head will quiver, which serves as a possible form of submission.[32] Greetings between males and females are common, with larger males being the most involved in meeting females. Most other non-antagonistic behavior occurs between mothers and their young. Mother and young reinforce their bond through grooming. A mother will groom her young while it is suckling or after it is finished suckling.[32] A joey will nuzzle its mother's pouch if it wants access to it.

Sexual activity of kangaroos consists of consort pairs.[48] Oestrous females roam widely and attract the attention of males with conspicuous signals.[48] A male will monitor a female and follow her every movement. He sniffs her urine to see if she is in oestrus, a process exhibiting the flehmen response. The male will then proceed to approach her slowly to avoid alarming her.[28] If the female does not run away, the male will continue by licking, pawing, and scratching her, and copulation will follow.[28] After copulation is over, the male will move on to another female. Consort pairing may take several days and the copulation is also long. Thus, a consort pair is likely to attract the attention of a rival male.[48] As larger males are tending bonds with females near oestrus, smaller males will tend to females that are farther from oestrus.[28] Dominant males can avoid having to sort through females to determine their reproductive status by searching for tending bonds held by the largest male they can displace without a fight.[28]

Fighting has been described in all species of kangaroos. Fights between kangaroos can be brief or long and ritualised.[32] In highly competitive situations, such as males fighting for access to oestrous females or at limited drinking spots, the fights are brief.[32] Both sexes will fight for drinking spots, but long, ritualised fighting or "boxing" is largely done by males. Smaller males fight more often near females in oestrus, while the large males in consorts do not seem to get involved. Ritualised fights can arise suddenly when males are grazing together. However, most fights are preceded by two males scratching and grooming each other.[32] One or both of them will adopt a high standing posture, with one male issuing a challenge by grasping the other male's neck with its forepaw. Sometimes, the challenge will be declined. Large males often reject challenges by smaller males. During fighting, the combatants adopt a high standing posture and paw at each other's heads, shoulders and chests. They will also lock forearms and wrestle and push each other as well as balance on their tails to kick each other in the abdomen.[32]

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