View source for Biology:Kangaroo

{{short description|Marsupial of the family Macropodidae}}
{{Use Australian English|date=August 2015}}
{{Paraphyletic group
| name = Kangaroo
| fossil_range = Early Miocene – Present
| image = Kangaroo Australia 01 11 2008 - retouch.JPG
| image_caption = A female [[Biology:Eastern grey kangaroo|eastern grey kangaroo]] 
| parent = Macropodidae
| auto = yes
| includes =
*''[[Biology:Macropus|Macropus]]''
*''Osphranter antilopinus''
*''Osphranter rufus''
| excludes = 
*All other ''[[Biology:Osphranter|Osphranter]]'' sp.
}}
[[File:RedRoo.JPG|thumb|upright=1|A male red kangaroo]]
[[File:Kangaroos c.1819 SLNSW FL8999009.jpg|thumb|upright=1|Red kangaroos, Liverpool Plains, Sydney, ca. 1819]]

'''Kangaroos''' are four [[Biology:Marsupial|marsupial]]s from the family [[Biology:Macropodidae|Macropodidae]] (macropods, meaning "large foot"). In common use the term is used to describe the largest species from this family, the [[Biology:Red kangaroo|red kangaroo]], as well as the [[Biology:Antilopine kangaroo|antilopine kangaroo]], [[Biology:Eastern grey kangaroo|eastern grey kangaroo]], and [[Biology:Western grey kangaroo|western grey kangaroo]].<ref name=MSW3>{{MSW3 Groves | pages= 64 & 66}}</ref> Kangaroos are indigenous to [[Earth:Australia (continent)|Australia]] and New Guinea. The Australian government estimates that 42.8&nbsp;million kangaroos lived within the commercial harvest areas of Australia in 2019, down from 53.2&nbsp;million in 2013.<ref>{{cite web|title=Kangaroo population estimates|url=https://www.environment.gov.au/system/files/pages/ee20f301-6c6c-44e4-aa24-62a32d412de5/files/kangaroo-statistics-states-2020.pdf|url-status=live|access-date=30 July 2021|website=Wildlife Trade|publisher=Government of Australia: Department Agriculture, Water and the Environment|archive-date=25 July 2021|archive-url=https://web.archive.org/web/20210725172442/https://www.environment.gov.au/system/files/pages/ee20f301-6c6c-44e4-aa24-62a32d412de5/files/kangaroo-statistics-states-2020.pdf}}</ref>
 
As with the terms "[[Biology:Wallaroo|wallaroo]]" and "[[Biology:Wallaby|wallaby]]", "kangaroo" refers to a [[Biology:Paraphyly|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.<ref name="Australian Wildlife" /> There are also the [[Biology:Tree-kangaroo|tree-kangaroo]]s, another type of macropod, which inhabit the [[Earth:Tropical rainforest|tropical rainforest]]s 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.<ref>{{Cite web|title=Live Science article|website=Live Science|date=2 March 2016|url=https://www.livescience.com/27400-kangaroos.html|url-status=live|access-date=14 November 2021|archive-date=14 November 2021|archive-url=https://web.archive.org/web/20211114041052/https://www.livescience.com/27400-kangaroos.html}}</ref> A general idea of the relative size of these informal terms could be:
* [[Biology:Wallaby|wallabies]]: head and body length of 45–105&nbsp;cm and tail length of 33–75&nbsp;cm; the dwarf wallaby (the smallest of all known macropod species) is 46&nbsp;cm long and weighs 1.6&nbsp;kg;
* [[Biology:Tree-kangaroo|tree-kangaroo]]s: ranging from [[Biology:Lumholtz's tree-kangaroo|Lumholtz's tree-kangaroo]]: body and head length of 48–65&nbsp;cm, tail of 60–74&nbsp;cm, weight of 7.2&nbsp;kg (16&nbsp;lb) for males and 5.9&nbsp;kg (13&nbsp;lb) for females; to the [[Biology:Grizzled tree-kangaroo|grizzled tree-kangaroo]]: length of 75–90&nbsp;cm (30 to 35 in) and weight of 8–15&nbsp;kg (18–33&nbsp;lb);
* [[Biology:Wallaroo|wallaroo]]s: the [[Biology:Black wallaroo|black wallaroo]] (the smaller of the two species) with a tail length of 60–70&nbsp;cm and weight of 19–22&nbsp;kg (41.8–48.5&nbsp;lb) for males and 13&nbsp;kg (28.6&nbsp;lb) for females;
* kangaroos: a large male can be 2 m (6&nbsp;ft 7 in) tall and weigh 90&nbsp;kg (200&nbsp;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.

{{Anchor|Teeth}}
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 [[Chemistry:Silica|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.<ref>[http://planet.uwc.ac.za/nisl/biodiversity/loe/page_192.htm Kangaroo: the teeth] {{webarchive|url=https://web.archive.org/web/20140417103429/http://planet.uwc.ac.za/nisl/biodiversity/loe/page_192.htm |date=17 April 2014 }}</ref> This process is known as [[Biology:Polyphyodont|polyphyodont]]y and, amongst other mammals, only occurs in [[Biology:Elephant|elephant]]s 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 [[Biology:Koala|koala]] are symbols of Australia. A kangaroo appears on the Australian coat of arms<ref>{{cite web |title=Commonwealth Coat of Arms |url=https://www.pmc.gov.au/government/commonwealth-coat-arms |work=Department of the Prime Minister and Cabinet |date=22 June 2016 |publisher=Australian Government |access-date=29 April 2020 |archive-date=30 July 2020 |archive-url=https://web.archive.org/web/20200730090610/https://www.pmc.gov.au/government/commonwealth-coat-arms |url-status=live }}</ref> and on some of its currency,<ref>{{cite web |title=One Dollar |url=https://www.ramint.gov.au/one-dollar |work=Royal Australian Mint |date=8 January 2016 |publisher=Australian Government |access-date=29 April 2020 |archive-date=12 June 2018 |archive-url=https://web.archive.org/web/20180612144800/https://www.ramint.gov.au/one-dollar |url-status=live }}</ref> and is used as a logo for some of Australia's most well-known organisations, such as [[Company:Qantas|Qantas]],<ref>{{cite web|title=The Kangaroo Symbol|url=http://www.qantas.com.au/info/about/history/details19|work=Qantas|archive-url=https://web.archive.org/web/20060414182719/http://www.qantas.com.au/info/about/history/details19|archive-date=14 April 2006}}</ref> and as the [[Roundel|roundel]] of the {{wipe|Royal Australian Air Force}}.<ref>{{cite web|url=http://www.airforce.gov.au/About_us/About_the_RAAF/Air_Force_Ensign/?RAAF-8f1IO5DsOyuE6wai0uL8r0DjCUFX+enq|title=RAAF Ensign and Roundel|author=Air Force|access-date=3 January 2013|archive-date=15 January 2013|archive-url=https://web.archive.org/web/20130115170056/http://airforce.gov.au/About_us/About_the_RAAF/Air_Force_Ensign/?RAAF-8f1IO5DsOyuE6wai0uL8r0DjCUFX+enq|url-status=live}}</ref> 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, [[Biology:Kangaroo leather|leather hide]]s, and to protect grazing land.<ref>{{cite web |url=http://www.kangaroo-industry.asn.au/morinfo/BACKGR1.HTM |title=Kangaroo Industry Background Kangaroo Industries Association of Australia. July 2008 |publisher=Kangaroo-industry.asn.au |date=31 July 1997 |access-date=5 April 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090205023954/http://www.kangaroo-industry.asn.au/morinfo/BACKGR1.HTM |archive-date=5 February 2009  }}</ref> [[Biology:Kangaroo meat|Kangaroo meat]] has perceived health benefits for human consumption compared with traditional meats due to the low level of fat on kangaroos.<ref>{{Cite news|last=Dow|first=Steve|title=An industry that's under the gun|url=http://www.smh.com.au/news/environment/an-industry-thats-under-the-gun/2007/09/25/1190486311919.html?page=fullpage|access-date=2 October 2011|newspaper=The Sydney Morning Herald|date=26 September 2007|archive-date=3 July 2017|archive-url=https://web.archive.org/web/20170703024346/http://www.smh.com.au/news/environment/an-industry-thats-under-the-gun/2007/09/25/1190486311919.html?page=fullpage|url-status=live}}</ref>

== Terminology ==
The word ''kangaroo'' derives from the Guugu Yimithirr word ''gangurru'', referring to [[Biology:Eastern grey kangaroo|eastern grey kangaroo]]s.<ref>{{cite web|title=Etymology of mammal names in English|publisher=IberiaNature|url=http://iberianature.com/britainnature/miscellaneous/etymology-of-mammal-names-in-english/|access-date=18 June 2011|archive-date=21 October 2018|archive-url=https://web.archive.org/web/20181021231809/http://iberianature.com/britainnature/miscellaneous/etymology-of-mammal-names-in-english/|url-status=live}}</ref><ref>{{Cite book|last=Stephens|first=S.E.|author2=Cilento, Raphael|title=Introduction to Cooktown and its Museum|publisher=National Trust of Queensland|year=1976|asin=B0000CPFEZ}}</ref> 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.<ref>{{Cite web |url=http://andc.anu.edu.au/sites/default/files/vocab_aussie_eng.pdf |title=Bruce Moore, ''The Vocabulary of Australian English'', Australian National Dictionary Centre, Australian National University |access-date=8 April 2013 |archive-date=11 April 2013 |archive-url=https://web.archive.org/web/20130411064602/http://andc.anu.edu.au/sites/default/files/vocab_aussie_eng.pdf |url-status=live }}</ref> 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".<ref>{{cite web|title=Believe it or nuts. (Columns/Posted 11/09/99)|publisher=Word Detective|url=http://www.word-detective.com/110999.html#kangaroo|access-date=18 June 2011|archive-date=7 June 2011|archive-url=https://web.archive.org/web/20110607051530/http://www.word-detective.com/110999.html#kangaroo|url-status=live}}</ref> 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.<ref name=jennings/> 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.<ref name=jennings>{{cite web |last1=Jennings |first1=Ken |title=The Debunker: Where Does the Word "Kangaroo" Come From? |url=https://www.woot.com/blog/post/the-debunker-where-does-the-word-kangaroo-come-from |website=woot.com |publisher=Woot |date=7 August 2019 |access-date=16 December 2019 |archive-date=17 December 2019 |archive-url=https://web.archive.org/web/20191217102123/https://www.woot.com/blog/post/the-debunker-where-does-the-word-kangaroo-come-from |url-status=live }}</ref><ref>{{cite journal |last=Haviland |first=John B. |year=1974 |title=A last look at Cook's Guugu-Yimidhirr wordlist |journal=Oceania |volume=44 |issue=3 |pages=216–232 |url=http://www.anthro.ucsd.edu/~jhaviland/Publications/HavilandOceania.pdf |access-date=13 April 2008 |doi=10.1002/j.1834-4461.1974.tb01803.x |archive-date=27 March 2012 |archive-url=https://web.archive.org/web/20120327074409/http://www.anthro.ucsd.edu/~jhaviland/Publications/HavilandOceania.pdf |url-status=live }}</ref> 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.<ref>{{cite book |last1=King |first1=Phillip Parker |title=Narrative of a Survey of the Intertropical and Western Coasts of Australia Vol. 1 |date=1827 |publisher=John Murray |location=London |url=https://archive.org/details/dli.granth.71314/page/368/mode/1up}}</ref> There are similar, more credible stories of naming confusion, such as with the Yucatán Peninsula.<ref name=jennings/>

Kangaroos are often colloquially referred to as "roos".<ref>{{cite web|title=Roo |work=Compact Oxford English Dictionary |publisher=Ask Oxford.com |url=http://www.askoxford.com/concise_oed/roo?view=uk |access-date=31 December 2006 |url-status=dead |archive-url=https://web.archive.org/web/20070211134324/http://www.askoxford.com/concise_oed/roo?view=uk |archive-date=11 February 2007 }}</ref> Male kangaroos are called bucks, boomers, jacks, or old men; females are does, flyers, or jills; and the young ones are joeys.<ref name="sandiego">{{cite web|title=Kangaroo and Wallaby|url=http://www.sandiegozoo.org/animalbytes/t-kangaroo.html|work=San Diego Zoo|publisher=Zoological Society of San Diego|access-date=2 October 2011|url-status=dead|archive-url=https://web.archive.org/web/20110927154255/http://www.sandiegozoo.org/animalbytes/t-kangaroo.html|archive-date=27 September 2011}}</ref> The collective noun for a group of kangaroos is a mob, court, or troupe.<ref name="Kidcyber">{{cite web|last1=Sydenham |first1=S |last2=Thomas |first2=R |title=Kangaroos |url=http://www.kidcyber.com.au/topics/kanga.htm |work=Kidcyber |access-date=2 October 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110903001135/http://www.kidcyber.com.au/topics/kanga.htm |archive-date=3 September 2011 }}</ref>

== Taxonomy and description ==
[[File:Sthenurus.jpg|thumb|upright=1|The palatal view of a ''Sthenurus'' sp. skull]]
[[File:The Kongouro from New Holland (Kangaroo) NMM ZBA5754 (cropped).jpg|thumb|upright=1|''The Kongouro from New Holland'', a 1772 painting of a kangaroo by George Stubbs]]
There are four extant species that are commonly referred to as kangaroos:
* The [[Biology:Red kangaroo|red kangaroo]] (''Osphranter rufus'')<ref name="afd2020">{{cite web|title=Names List for MACROPODIDAE, Australian Faunal Directory|url=https://biodiversity.org.au/afd/taxa/MACROPODIDAE/names|publisher=Australian Biological Resources Study, Australian Department of the Environment and Energy|access-date=1 March 2020|date=13 February 2020|archive-date=2 April 2020|archive-url=https://web.archive.org/web/20200402181724/https://biodiversity.org.au/afd/taxa/MACROPODIDAE/names|url-status=live}}</ref> is the largest surviving [[Biology:Marsupial|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.<ref name=dawson2012>{{cite book|last=Dawson|first=Terence|title=Kangaroos|edition=2nd|year=2012|publisher=CSIRO Publishing|location=Collingwood, VIC}}</ref> A large male can be 2 metres (6&nbsp;ft 7 in) tall and weighs 90&nbsp;kg (200&nbsp;lb).<ref name="reds">{{cite web|title=Red Kangaroo|url=http://animals.nationalgeographic.com/animals/mammals/red-kangaroo/|work=NAT GEO Wild|publisher=National Geographic Society|access-date=2 October 2011|date=11 November 2010|archive-date=16 September 2015|archive-url=https://web.archive.org/web/20150916000231/http://animals.nationalgeographic.com/animals/mammals/red-kangaroo/|url-status=dead}}</ref>
* The [[Biology:Eastern grey kangaroo|eastern grey kangaroo]] (''Macropus giganteus'')<ref name="afd2020" /> 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 km<sup>2</sup> 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.<ref name=dawson2012 />
* The [[Biology:Western grey kangaroo|western grey kangaroo]] (''Macropus fuliginosus'')<ref name="afd2020" /> is slightly smaller again at about 54&nbsp;kg (119&nbsp;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 [[Chemistry:Sodium fluoroacetate|sodium fluoroacetate]], which indicates a possible origin from the southwest region of Australia.<ref name=dawson2012 />
* The [[Biology:Antilopine kangaroo|antilopine kangaroo]] (''Osphranter antilopinus'')<ref name="afd2020" /> 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.<ref name=dawson2012 />

In addition, there are about 50 smaller macropods closely related to the kangaroos in the family [[Biology:Macropodidae|Macropodidae]]. Kangaroos and other macropods share a common ancestor with the [[Biology:Phalangeridae|Phalangeridae]] from the Middle Miocene.<ref>{{cite journal |author=Rice, W.D.L. |title=Historical introduction to studies on the evolution and phylogeny of the Macropodidae |journal=Australian Mammalogy |volume=2 |pages=1–14 |year=1978 |doi=10.1071/AM78001 |s2cid=254709571 }}</ref> 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.<ref name = "McCullough 2000"/> From the Late Miocene through the Pliocene and into the [[Earth:Pleistocene|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 [[Biology:Foregut fermentation|foregut fermentation]].<ref name = "McCullough 2000"/> The most numerous early macropods, the [[Biology:Balbaridae|Balbaridae]] and the Bulungamayinae, became extinct in the Late Miocene around 5–10 mya.<ref name=Tyndale2005>{{cite book |author=Tyndale-Biscoe, H |title=Life of Marsupials |publisher=CSIRO Publishing |year=2005 |page=302 |isbn=978-0-643-06257-3 |url=https://books.google.com/books?id=KqtlPZJ9y8EC&pg=PA302 |access-date=9 November 2015 |archive-date=1 January 2016 |archive-url=https://web.archive.org/web/20160101053114/https://books.google.com/books?id=KqtlPZJ9y8EC&pg=PA302 |url-status=live }}</ref> There is dispute over the relationships of the two groups to modern kangaroos and [[Biology:Potoroidae|rat-kangaroo]]s. Some argue that the balbarines were the ancestors of rat-kangaroos and the bulungamayines were the ancestors of kangaroos.<ref>{{cite journal |vauthors=Cooke B, Kear B |title=Evolution and diversity of kangaroos (Macropodoidea, Marsupialia) |journal=Australian Mammalogy |volume=21 |pages=27–29 |year=1999 }}</ref> while others hold the contrary view.<ref>{{cite book |author=Flannery, T.F. |chapter=Phylogeny of the Macropodoidea; a study in convergence |editor1=Grigg G. |editor2=Jarman P. |editor3=Hume I.D. |title=Kangaroos, Wallabies and Rat-kangaroos |publisher=Surrey Beatty |location=Sydney |year=1989 |isbn=978-0-949324-22-1 |pages=1–46 }}</ref>

The middle to late bulungamayines, ''[[Biology:Ganguroo|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.<ref name=Tyndale2005/> Species related to the modern grey kangaroos and [[Biology:Wallaroo|wallaroo]]s 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.<ref name = "Dawson 1995"/>

The first kangaroo to be exhibited in the Western world was an example shot by John Gore, an officer on Captain Cook's ship, [[Engineering:HMS Endeavour|HMS ''Endeavour'']], in 1770.<ref>{{Cite journal |title=Captain John Gore |url=http://www.nma.gov.au/shared/libraries/attachments/friends/archive/in_the_national_museum_captain_john_gore/files/17814/Captain_John_Gore_rf.pdf |journal=FRiENDS |volume=17 |issue=2 |issn=1323-5826 |date=June 2006 |access-date=2 October 2011 |page=18 |first=Johanna |last=Parker |archive-url=https://web.archive.org/web/20120121210124/http://www.nma.gov.au/shared/libraries/attachments/friends/archive/in_the_national_museum_captain_john_gore/files/17814/Captain_John_Gore_rf.pdf |archive-date=21 January 2012 |url-status=dead  }}</ref><ref>{{Cite journal|last1=Cowley|first1=Des|last2=Hubber|first2=Brian|title=Kangaroo|journal=The La Trobe Journal|year=2000|issue=66|pages=4–[https://web.archive.org/web/20190628083125/http://www.slv.vic.gov.au/latrobejournal/issue/latrobe-66/t1-g-t2.html 5]|url=http://www.slv.vic.gov.au/latrobejournal/issue/latrobe-66/t1-g-t2.html|archive-url=https://web.archive.org/web/20190628083125/http://www.slv.vic.gov.au/latrobejournal/issue/latrobe-66/t1-g-t2.html|archive-date=28 June 2019|access-date=2 October 2011|editor1-first=John|editor1-last=Barnes|editor2-first=Sandra|editor2-last=Burt|issn=1441-3760}}</ref> The animal was shot and its skin and skull transported back to England whereupon it was stuffed (by [[Biology:Taxidermy|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.<ref>The "i" newspaper, 21 June 2013. page 2</ref>

=== Comparison with wallabies ===
Kangaroos and [[Biology:Wallaby|wallabies]] belong to the same taxonomic family ([[Biology:Macropodidae|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 [[Biology:Macropodidae|macropod]] that is smaller than a kangaroo or a [[Biology:Wallaroo|wallaroo]] that has not been designated otherwise.<ref name="Australian Wildlife">{{cite web|title=The Kangaroo |url=http://www.australianwildlife.com.au/kangaroo.htm |access-date=6 November 2013 |url-status=dead |archive-url=https://web.archive.org/web/20140125064953/http://australianwildlife.com.au/kangaroo.htm |archive-date=25 January 2014 }}</ref>

== Biology and behaviour ==
[[File:Kangaroo-in-flight.jpg|thumb|left|upright=0.7|A Tasmanian eastern grey kangaroo in motion]]
[[File:Kangaroos Maranoa.JPG|thumb|upright=0.7|Kangaroos in their native grassland habitat]]
[[File:Kangur.rudy.drs.jpg|thumb|left|upright=0.7|A red kangaroo grazing]]
[[File:Group of Macropus fuliginosus Darling Range 05010.JPG|thumb|upright=0.7|[[Biology:Western grey kangaroo|Western grey kangaroo]]s]]

=== Locomotion ===
Kangaroos are the only large mammals to use [[Biology:Jumping|hopping]] on two legs as their primary means of [[Biology:Animal locomotion|locomotion]].<ref>{{cite news |last1=Briggs |first1=Helen |title=When did the kangaroo hop? Scientists have the answer |url=https://www.bbc.co.uk/news/science-environment-47130734 |access-date=5 February 2023 |work=BBC News |date=6 February 2019 |quote=Living kangaroos are the only large mammal to use hopping on two legs as their main form of locomotion.}}</ref> The comfortable hopping speed for a red kangaroo is about {{convert|20–25|kph|abbr=on}}, but speeds of up to {{convert|70|kph|abbr=on}} can be attained over short distances, while it can sustain a speed of {{convert|40|kph|abbr=on}} for nearly {{convert|2|km|abbr=on}}.<ref name="secret">{{cite book | last = Penny | first = Malcolm | title = The Secret World of Kangaroos | publisher = Raintree Steck-Vaughn | year = 2002 | location = Austin TX | isbn = 978-0-7398-4986-6 | url = https://books.google.com/books?id=NNLpLfdP5GwC&q=%2270+km%22 | access-date = 8 May 2020 | archive-date = 16 August 2021 | archive-url = https://web.archive.org/web/20210816140648/https://books.google.com/books?id=NNLpLfdP5GwC&q=%2270+km%22 | url-status = live }}</ref> During a hop, the powerful gastrocnemius muscles lift the body off the ground while the smaller plantaris muscle, which attaches near the large fourth toe, is used for push-off. Seventy percent of potential energy is stored in the elastic tendons.<ref>{{cite book |last1=Jackson |first1=S |last2=Vernes |first2=K |year=2010|title=Kangaroo: Portrait of an Extraordinary Marsupial|publisher=Allen and Unwin|pages=139–140|isbn=9781741759037}}</ref> At slow speeds, it employs pentapedal locomotion, using its tail to form a tripod with its two forelimbs while bringing its hind feet forward. Both pentapedal walking and fast hopping are energetically costly. Hopping at moderate speeds is the most energy efficient, and a kangaroo moving above {{convert|15|kph|abbr=on}} maintains energy consistency more than similarly sized animals running at the same speed.<ref name="Dawson 1995"/>

=== Diet ===
Kangaroos have single-chambered stomachs quite unlike those of [[Biology:Cattle|cattle]] and [[Biology:Sheep|sheep]], which have four compartments.<ref name=Hume1984>{{cite journal | last = Hume | first = I.D. | year = 1984 | title = Principal Features of Digestion in Kangaroos | journal = Proceedings of the Nutritional Society of Australia | volume = 9 | url = http://apjcn.nhri.org.tw/server/apjcn/ProcNutSoc/1980-1989/1984/1984%20p76-81.pdf | pages = 76–81 | access-date = 15 October 2017 | archive-date = 15 October 2017 | archive-url = https://web.archive.org/web/20171015150859/http://apjcn.nhri.org.tw/server/apjcn/ProcNutSoc/1980-1989/1984/1984%20p76-81.pdf | url-status = live }}</ref><ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|page= 347|isbn= 978-0-03-910284-5}}</ref> They sometimes regurgitate the vegetation they have eaten, chew it as [[Biology:Cud|cud]], and then swallow it again for final digestion. However, this is a different, more strenuous, activity than it is in [[Biology:Ruminant|ruminant]]s, and does not take place as frequently.<ref name=Vendl2017>{{cite journal | author = Vendl, C. | display-authors = etal | year = 2017 | title = Merycism in western grey (''Macropus fuliginosus'') and red kangaroos (''Macropus rufus'') | journal = Mammalian Biology | volume = 86 | pages = 21–26 | doi = 10.1016/j.mambio.2017.03.005| doi-access = free }}</ref>

Different species of kangaroos have different diets, although all are strict herbivores. The eastern grey kangaroo is predominantly a [[Biology:Grazing|grazer]], and eats a wide variety of grasses, whereas some other species such as the red kangaroo include significant amounts of [[Biology:Shrub|shrub]]s in their diets. Smaller species of kangaroos also consume [[Biology:Hypogeal|hypogeal]] fungi. Many species are nocturnal,<ref name="archive">{{cite web|last=McGuinness|first=Keith|title=Re: Kangaroos|url=http://www.madsci.org/posts/archives/dec96/845059250.Zo.r.html|work=MadSci Network|access-date=2 October 2011|date=25 November 1996|archive-date=18 October 2011|archive-url=https://web.archive.org/web/20111018075222/http://www.madsci.org/posts/archives/dec96/845059250.Zo.r.html|url-status=live}}</ref> and crepuscular,<ref name="colzoo">{{cite web|title=From Boomers to Blue fliers: Fun facts About Kangaroos!!|url=http://www.colszoo.org/animalareas/austral/kangfact.html|work=Columbus Zoo and Aquarium|archive-url=https://web.archive.org/web/20040226032907/http://www.colszoo.org/animalareas/austral/kangfact.html|archive-date=26 February 2004}}</ref><ref name="nocturn2">{{cite web|url=http://www.dfat.gov.au/facts/kangaroos.html |title=About Australia: Kangaroos |publisher=Department of Foreign Affairs and Trade |access-date=6 June 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120527162537/http://www.dfat.gov.au/facts/kangaroos.html |archive-date=27 May 2012 }}</ref> usually spending the hot days resting in shade, and the cool evenings, nights and mornings moving about and feeding.

==== Absence of digestive methane release ====
Despite having herbivorous diets similar to [[Biology:Ruminant|ruminant]]s such as cattle, which release large quantities of digestive [[Chemistry:Methane|methane]] through [[Physics:Breathing|exhaling]] and eructation (burping), kangaroos release virtually none. The [[Chemistry:Hydrogen|hydrogen]] byproduct of [[Biology:Fermentation|fermentation]] is instead converted into [[Chemistry:Acetate|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 [[Chemistry:Greenhouse gas|greenhouse gas]] effect of methane is 23 times greater than [[Chemistry:Carbon dioxide|carbon dioxide]] per molecule.<ref>{{cite journal |last1=Vendl |first1=C. |last2=Clauss |first2=M. |last3=Stewart |first3=M. |last4=Leggett |first4=K. |last5=Hummel |first5=J. |last6=Kreuzer |first6=M. |last7=Munn |first7=A. |title=Decreasing methane yield with increasing food intake keeps daily methane emissions constant in two foregut fermenting marsupials, the western grey kangaroo and red kangaroo |journal=Journal of Experimental Biology |date=4 November 2015 |volume=218 |issue=21 |pages=3425–3434 |doi=10.1242/jeb.128165 |pmid=26538176 |doi-access=free }}</ref>

=== Social and sexual behavior ===
[[File:Fighting red kangaroos 1.jpg|thumb|upright=1|Two male red kangaroos boxing]]
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.<ref name="Kidcyber"/> The size and stability of mobs vary between geographic regions,<ref name = "McCullough 2000">{{harvnb|McCullough|2000}}</ref><ref>{{cite journal |last1=Green-Barber |first1=JM |last2=Old |first2=JM |year=2018 |title=Town roo, country roo: a comparison of behaviour in eastern grey kangaroos (''Macropus giganteus'') in developed and natural landscapes |journal=Australian Zoologist |volume=39 |issue=3 |pages=520–533 |doi=10.7882/AZ.2018.019|s2cid=134213663 |doi-access=free }}</ref><ref>{{cite journal |last1=Green-Barber |first1=JM |last2=Old |first2=JM |year=2018 |title=The genetic relatedness of a peri-urban population of eastern grey kangaroos |journal=BMC Research Notes |volume=11 |issue=1 |pages=856 |doi=10.1186/s13104-018-3969-2|pmid=30514393 |pmc=6280538 |doi-access=free }}</ref> with eastern Australia having larger and more stable aggregations than in arid areas farther west.<ref name="McCullough 2000"/> Larger aggregations display high amounts of interactions and complex social structures, comparable to that of [[Biology:Ungulate|ungulate]]s.<ref name="McCullough 2000"/> One common behavior is nose touching and sniffing, which mostly occurs when an individual joins a group.<ref name="Dawson 1995">{{cite book |author=Dawson, Terence J. |title=Kangaroos: Biology of the Largest Marsupials |publisher=Cornell University Press/Comstock Publishing |year=1995 |isbn=978-0-8014-8262-5 |url-access=registration |url=https://archive.org/details/kangaroosbiology00daws }}</ref> 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.<ref name="Dawson 1995"/> 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.<ref name="Dawson 1995"/>  A joey will nuzzle its mother's pouch if it wants access to it.

{{Anchor|Sexual behavior}}
Sexual activity of kangaroos consists of consort pairs.<ref name = "Gansloßer 1995"/> Oestrous females roam widely and attract the attention of males with conspicuous signals.<ref name = "Gansloßer 1995">{{cite journal |author=Gansloßer, Udo |title=Courtship behaviour in Macropodoidea (kangaroos, wallabies and rat kangaroos)&nbsp;– phylogenetic and ecological influences on ritualization |journal=Mammal Review |volume=25 |issue=3 |pages=131–157 |year=1995 |doi=10.1111/j.1365-2907.1995.tb00453.x }}</ref> 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 [[Biology:Flehmen response|flehmen response]]. The male will then proceed to approach her slowly to avoid alarming her.<ref name = "McCullough 2000"/> If the female does not run away, the male will continue by licking, pawing, and scratching her, and [[Biology:Copulation (zoology)|copulation]] will follow.<ref name = "McCullough 2000"/> 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.<ref name = "Gansloßer 1995"/> As larger males are tending bonds with females near oestrus, smaller males will tend to females that are farther from oestrus.<ref name = "McCullough 2000"/> [[Dominance (ethology)|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.<ref name = "McCullough 2000"/>

Fighting has been described in all species of kangaroos. Fights between kangaroos can be brief or long and ritualised.<ref name="Dawson 1995"/> In highly competitive situations, such as males fighting for access to oestrous females or at limited drinking spots, the fights are brief.<ref name="Dawson 1995"/> 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.<ref name="Dawson 1995"/> 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.<ref name="Dawson 1995"/>

Brief fights are similar, except there is no forearm locking. The losing combatant seems to use kicking more often, perhaps to parry the thrusts of the eventual winner. A winner is decided when a kangaroo breaks off the fight and retreats. Winners are able to push their opponents backwards or down to the ground. They also seem to grasp their opponents when they break contact and push them away.<ref name="Dawson 1995"/> The initiators of the fights are usually the winners. These fights may serve to establish dominance hierarchies among males, as winners of fights have been seen to displace their opponent from resting sites later in the day.<ref name="Dawson 1995"/> Dominant males may also pull grass to intimidate subordinate ones.<ref name = "McCullough 2000"/>

=== Predators ===
Kangaroos have a few natural predators. The [[Biology:Thylacine|thylacine]], considered by palaeontologists to have once been a major natural predator of the kangaroo, is now [[Biology:Extinction|extinct]]. Other extinct predators included the [[Biology:Marsupial lion|marsupial lion]], ''[[Biology:Megalania|Megalania]]'' and ''Wonambi''. However, with the arrival of humans in Australia at least 50,000 years ago and the introduction of the [[Biology:Dingo|dingo]] about 5,000 years ago, kangaroos have had to adapt.

Along with dingoes, introduced species such as foxes, [[Biology:Feral cat|feral cat]]s, and both domestic and feral dogs, pose a threat to kangaroo populations. Kangaroos and wallabies are adept [[Biology:Aquatic locomotion|swimmers]], and often flee into waterways if presented with the option. If pursued into the water, a large kangaroo may use its forepaws to hold the predator underwater so as to [[Medicine:Drowning|drown]] it.<ref name="camuseum">{{cite web|title=Kangaroos|url=http://www.nature.ca/notebooks/english/kanga.htm|work=Natural History Notebooks|publisher=Canadian Museum of Nature|access-date=2 October 2011|date=3 May 2011|archive-date=9 January 2016|archive-url=https://web.archive.org/web/20160109223806/http://www.nature.ca/notebooks/english/kanga.htm|url-status=live}}</ref> Another defensive tactic described by witnesses is catching the attacking dog<!--Just dogs, or other predators as well?--> with the forepaws and disembowelling it with the hind legs.

=== Adaptations ===
[[File:Kangaroo and joey03.jpg|thumb|upright=0.7|Kangaroo and joey in pouch]]
[[File:Kaenguru Hinterfuss-drawing.jpg|thumb|upright=0.7|The hind leg of a kangaroo]]
Kangaroos have developed a number of adaptations to a dry, infertile country and highly variable climate. As with all [[Biology:Marsupial|marsupial]]s, the young are born at a very early stage of development—after a gestation of 31–36 days. At this stage, only the forelimbs are somewhat developed, to allow the newborn to climb to the pouch and attach to a [[Biology:Teat|teat]]. In comparison, a human [[Biology:Embryo|embryo]] at a similar stage of development would be at about 7 weeks gestation (even in a modern intensive care unit, premature babies born at less than 23 weeks gestation are usually not mature enough to survive). When the joey is born, it is about the size of a [[Biology:Phaseolus lunatus|lima bean]]. The joey will usually stay in the pouch for about 9 months (180–320 days for the Western Grey) before starting to leave the pouch for small periods of time. It is usually fed by its mother until reaching 18 months.

The female kangaroo is usually pregnant in permanence, except on the day she gives birth; however, she has the ability to freeze the development of an embryo until the previous joey is able to leave the pouch. This is known as [[Biology:Embryonic diapause|embryonic diapause]] and will occur in times of drought and in areas with poor food sources. The composition of the milk produced by the mother varies according to the needs of the joey. In addition, the mother is able to produce two different kinds of milk simultaneously for the newborn and the older joey still in the pouch.

Unusually, during a dry period, males will not produce sperm and females will conceive only if enough rain has fallen to produce a large quantity of green vegetation.<ref name="animal">{{cite book | last = Burnie | first = David |author2=Don E. Wilson | title = Animal | publisher=DK | year = 2001 | location = New York NY | pages = 99–101 | isbn = 978-0-7894-7764-4}}</ref>

Kangaroos and wallabies have large, elastic tendons in their hind legs. They store elastic strain energy in the [[Biology:Tendon|tendon]]s of their large hind legs, providing most of the energy required for each hop by the spring action of the tendons rather than by any muscular effort.<ref name="tendons & hopping">{{cite book| last=Dawson| first=Terence J. (Professor UNSW)| title=Kangaroos: Biology of the largest marsupials| year=1998| publisher=Comstock Pub. Associates| location=Ithaca, N.Y.| isbn=9780801482625| pages=7–11| url=https://books.google.com/books?id=KNxIlprcmTYC&q=ancestors+of+kangaroos&pg=PA6| edition=2nd| access-date=3 August 2013| format=Paperback| archive-date=16 May 2021| archive-url=https://web.archive.org/web/20210516185428/https://books.google.com/books?id=KNxIlprcmTYC&q=ancestors+of+kangaroos&pg=PA6| url-status=live}}</ref> This is true in all animal species which have muscles connected to their skeletons through elastic elements such as tendons, but the effect is more pronounced in kangaroos.

There is also a link between the hopping action and breathing: as the feet leave the ground, air is expelled from the lungs; bringing the feet forward ready for landing refills the lungs, providing further energy efficiency. Studies of kangaroos and [[Biology:Wallaby|wallabies]] have demonstrated, beyond the minimum energy expenditure required to hop at all, increased speed requires very little extra effort (much less than the same speed increase in, say, a horse, dog or human), and the extra energy is required to carry extra weight. For kangaroos, the key benefit of hopping is not speed to escape predators—the top speed of a kangaroo is no higher than that of a similarly sized quadruped, and the Australian native predators are in any case less fearsome than those of other countries—but economy: in an infertile country with highly variable weather patterns, the ability of a kangaroo to travel long distances at moderately high speed in search of food sources is crucial to survival.

New research has revealed that a kangaroo's tail acts as a third leg rather than just a balancing strut. Kangaroos have a unique three-stage walk where they plant their front legs and tail first, then push off their tail, followed lastly by the back legs. The propulsive force of the tail is equal to that of both the front and hind legs combined and performs as much work as what a human leg walking can at the same speed.<ref>{{cite news|title=Kangaroos use tail like a leg to walk|url=http://www.australiangeographic.com.au/news/2014/07/kangaroos-use-tail-to-walk|access-date=18 November 2014|website=Australian Geographic|date=2 July 2014|archive-date=10 November 2014|archive-url=https://web.archive.org/web/20141110100429/http://www.australiangeographic.com.au/news/2014/07/kangaroos-use-tail-to-walk|url-status=live}}</ref>

A [[Biology:DNA sequencing|DNA sequencing]] project of the [[Biology:Genome|genome]] of a member of the kangaroo family, the [[Biology:Tammar wallaby|tammar wallaby]], was started in 2004. It was a collaboration between Australia (mainly funded by the State of Victoria) and the [[Organization:National Institutes of Health|National Institutes of Health]] in the US.<ref name="genome">{{Cite press release|author=Spencer, Geoff |title=Kangaroo Hops in Line for Genome Sequencing |url=http://www.nih.gov/news/pr/jun2004/nhgri-08.htm |work=National Human Genome Research Institute |publisher=National Institutes of Health |access-date=2 October 2011 |date=8 June 2004 |url-status=dead |archive-url=https://web.archive.org/web/20111002020057/http://www.nih.gov/news/pr/jun2004/nhgri-08.htm |archive-date=2 October 2011 }}</ref> The tammar's genome was fully sequenced in 2011.<ref name="Renfree/Papenfuss">{{cite journal |author=Renfree M. B. |author2=Papenfuss, A. T. |author3=Deakin, J. E. |display-authors=0 | title=Genome sequence of an Australian kangaroo, ''Macropus eugenii'', provides insight into the evolution of mammalian reproduction and development.| journal=Genome Biology| volume=12| issue=8| pages=R81| pmid=21854559| doi=10.1186/gb-2011-12-8-r81| pmc=3277949 | date=19 August 2011 |doi-access=free }}</ref> The genome of a marsupial such as the kangaroo is of great interest to scientists studying [[Biology:Comparative genomics|comparative genomics]], because marsupials are at an ideal degree of evolutionary divergence from humans: [[Biology:Mouse|mice]] are too close and have not developed many different functions, while birds are genetically too remote. The dairy industry could also benefit from this project.<ref>{{cite journal|title=The tammar wallaby: A model to examine endocrine and local control of lactation|journal=IUBMB Life|last1=Brennan|first1=A. J.|last2=Sharp|first2=J. A.|last3=Digby|first3=M. R.|last4=Nicholas|first4=K. R.|volume=59|issue=3|pages=146–150|year=2007|doi=10.1080/15216540701335724|doi-access=free|pmid=17487685}}</ref>

=== Blindness ===
Eye disease<!--Proper name(s)?--> is rare but not new among kangaroos. The first official report of kangaroo blindness took place in 1994, in central New South Wales. The following year, reports of blind kangaroos appeared in Victoria and South Australia. By 1996, the disease had spread "across the desert to Western Australia".<ref name=nwf/> Australian authorities were concerned the disease could spread to other livestock and possibly humans. Researchers at the Australian Animal Health Laboratories in Geelong detected a virus called the Wallal virus in two species of [[Biology:Midge|midge]]s, believed to have been the carriers.<ref>{{cite journal |last=Hooper |first=P |title=Kangaroo blindness and some other new viral diseases in Australia |journal=Australian Veterinary Journal |volume=77 |issue=8 |pages=514–5 |date=August 1999 |url=http://www.ava.com.au/avj/9908/99080514.pdf |access-date=31 December 2006 |doi=10.1111/j.1751-0813.1999.tb12122.x |pmid=10494397 |archive-url=https://web.archive.org/web/20060917145454/http://www.ava.com.au/avj/9908/99080514.pdf |archive-date=17 September 2006 |url-status=dead  }}</ref><ref>{{cite journal | doi = 10.1071/EC87p36 | title = Viruses on the hop | journal=Ecos | issue = 87 |date=Autumn 1996 | author1 = <!-- Please add first missing authors to populate metadata. --> | volume=1996 | page=36}}</ref> Veterinarians also discovered fewer than 3% of kangaroos exposed to the virus developed blindness.<ref name=nwf>{{cite web | last = Harrison | first = George | title = Everything You Always Wanted to Know About Kangaroos | date = September–October 1997 | publisher=National Wildlife Federation | archive-url  = https://web.archive.org/web/20051230075601/http://www.nwf.org/internationalwildlife/kangaroo.html | archive-date = 30 December 2005 | url = http://www.nwf.org/internationalwildlife/kangaroo.html}}</ref>

=== Reproduction and life cycle ===
[[File:Joey in pouch.jpg|thumb|upright=0.7|A newborn joey sucking on a teat in the pouch]]
Kangaroo reproduction is similar to that of [[Biology:Opossum|opossum]]s. The egg (still contained in the shell membrane, a few micrometres thick, and with only a small quantity of yolk within it) descends from the [[Biology:Ovary|ovary]] into the [[Biology:Uterus|uterus]]. There it is fertilised and quickly develops into a neonate. Even in the largest kangaroo species (the [[Biology:Red kangaroo|red kangaroo]]), the neonate emerges after only 33 days. Usually, only one young is born at a time. It is blind, hairless, and only a few centimetres long; its hindlegs are mere stumps; it instead uses its more developed forelegs to climb its way through the thick fur on its mother's [[Biology:Abdomen|abdomen]] into the pouch, which takes about three to five minutes. Once in the pouch, it fastens onto one of the four teats and starts to feed. Almost immediately, the mother's sexual cycle starts again. Another egg descends into the uterus and she becomes sexually receptive. Then, if she mates and a second egg is fertilised, its development is temporarily halted. This is known as [[Biology:Embryonic diapause|embryonic diapause]], and will occur in times of drought and in areas with poor food sources. Meanwhile, the neonate in the pouch grows rapidly. After about 190 days, the baby ([[Biology:Marsupial#Early development|joey]]) is sufficiently large and developed to make its full emergence out of the pouch, after sticking its head out for a few weeks until it eventually feels safe enough to fully emerge. From then on, it spends increasing time in the outside world and eventually, after about 235 days, it leaves the pouch for the last time.<ref>[http://planet.uwc.ac.za/nisl/biodiversity/loe/page_193.htm Evolution of Biodiversity] {{Webarchive|url=https://web.archive.org/web/20160303182629/http://planet.uwc.ac.za/nisl/biodiversity/loe/page_193.htm |date=3 March 2016 }}, BCB705 Biodiversity, University of the Western Cape</ref> The [[Biology:Life expectancy|lifespan]] of kangaroos averages at six years in the wild<ref name="patricia">{{Cite book|last =Miller-Schroeder|first =Patricia|title =Kangaroos|series =The Untamed World|publisher =Raintree Steck-Vaughn|year =2002|url =https://books.google.com/books?id=zO_YyJfjK00C&q=kangaroo++lifespan|isbn =978-0-7398-4972-9|access-date =8 May 2020|archive-date =16 May 2021|archive-url =https://web.archive.org/web/20210516185636/https://books.google.com/books?id=zO_YyJfjK00C&q=kangaroo++lifespan|url-status =live}}</ref> to in excess of 20 years in captivity, varying by the species.<ref name="park">{{cite web|url=http://www.parkweb.vic.gov.au/education/factfiles/06.htm |title=Kangaroo |publisher=Parks Victoria |access-date=20 February 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110208012253/http://www.parkweb.vic.gov.au/education/factfiles/06.htm |archive-date=8 February 2011 }}</ref> Most individuals, however, do not reach maturity in the wild.<ref name="nowak">{{Cite book|last =Nowak|first =Ronald M.|title =Walker's mammals of the world|publisher =Johns Hopkins University Press|volume =2|year =1999|isbn =978-0-8018-5789-8|url =https://books.google.com/books?id=T37sFCl43E8C&q=kangaroo+average+life+span+wild&pg=PA125|access-date =4 October 2020|archive-date =16 May 2021|archive-url =https://web.archive.org/web/20210516185610/https://books.google.com/books?id=T37sFCl43E8C&q=kangaroo+average+life+span+wild&pg=PA125|url-status =live}}</ref><ref name="giganteus">{{cite web|url=http://animaldiversity.ummz.umich.edu/site/accounts/information/Macropus_giganteus.html|title=Macropus giganteus|last2=Wund|last1=Joo|first2=Matthew|first1=Michael S.|publisher=Animal Diversity Web, University of Michigan Museum of Zoology|access-date=20 February 2011|archive-date=29 June 2011|archive-url=https://web.archive.org/web/20110629053809/http://animaldiversity.ummz.umich.edu/site/accounts/information/Macropus_giganteus.html|url-status=live}}</ref>

== Interaction with humans ==
[[File:Ridpath's Universal history - an account of the origin, primitive condition and ethnic development of the great races of mankind, and of the principal events in the evolution and progress of the (14583958439).jpg|thumb|Aboriginal Australians hunting kangaroos]] 
The kangaroo has always been a very important animal for Aboriginal Australians, for its [[Biology:Kangaroo meat|meat]], hide, bone, and [[Biology:Tendon|tendon]]. Kangaroo hides were also sometimes used for recreation; in particular there are accounts of some tribes (Kurnai) using stuffed kangaroo scrotum as a ball for the traditional football game of marngrook. In addition, there were important Dreaming stories and ceremonies involving the kangaroo. Aherrenge is a current kangaroo dreaming site in the Northern Territory.<ref>{{cite web|title=Aherrenge Road|url=http://www.ntlis.nt.gov.au/placenames/view.jsp?id=24029|work=Northern Territory Land Information System|publisher=Northern Territory Government|access-date=2 October 2011|archive-date=22 April 2011|archive-url=https://web.archive.org/web/20110422163555/http://www.ntlis.nt.gov.au/placenames/view.jsp?id=24029|url-status=live}}</ref>

Unlike many of the smaller macropods, kangaroos have fared well since European settlement. European settlers cut down forests to create vast grasslands for sheep and cattle grazing, added stock watering points in arid areas, and have substantially reduced the number of dingoes. This overabundance has led to the view that the kangaroo is a pest animal as well as requiring regular culling and other forms of management. There is concern that the current management practices are leading to detrimental consequences for kangaroo welfare, landscape sustainability, biodiversity conservation, resilient agricultural production and Aboriginal health and culture.<ref>{{cite journal |last1=Read |first1=John L |last2=Wilson |first2=George R |last3=Coulson |first3=Graeme|last4=Cooney |first4=Rosie|last5=Paton |first5=David C|last6=Moseby |first6= Katherine E|last7=Snape |first7=Melissa A|last8=Edwards |first8=Melanie J|date= Nov 2021|title=Improving Kangaroo Management: A Joint Statement |url=https://onlinelibrary.wiley.com/doi/pdf/10.1111/emr.12467 |journal=Ecological Management & Restoration |volume=22 |issue=S1 |pages=186–192 |doi=10.1111/emr.12467 |bibcode=2021EcoMR..22S.186R |hdl=1885/285388 |s2cid=243491663 |access-date=2022-10-28|hdl-access=free }}</ref>
[[File:StateLibQld 1 100472.jpg|thumb|left|A kangaroo in a domestic setting, Queensland, Australia, circa 1900–1910]]
Kangaroos are shy and retiring by nature, and in normal circumstances present no threat to humans.  In 2003, Lulu, an eastern grey which had been hand-reared, saved a farmer's life by alerting family members to his location when he was injured by a falling tree branch. She received the RSPCA Australia National Animal Valour Award on 19 May 2004.<ref>{{cite news | last = Leung | first = Chee Chee | title = Lulu the kangaroo hops to the rescue | work = The Age | location = Australia | date = 23 September 2003 | url = http://www.theage.com.au/articles/2003/09/22/1064082926928.html?from=storyrhs | access-date = 10 January 2010 | archive-date = 11 September 2011 | archive-url = https://web.archive.org/web/20110911165840/http://www.theage.com.au/articles/2003/09/22/1064082926928.html?from=storyrhs | url-status = live }}</ref><ref>{{cite news | title =Life-saving kangaroo wins award | work =BBC News | date =29 April 2004 | url =http://news.bbc.co.uk/2/hi/asia-pacific/3667733.stm | access-date =10 January 2010 | archive-date =18 September 2010 | archive-url =https://web.archive.org/web/20100918061035/http://news.bbc.co.uk/2/hi/asia-pacific/3667733.stm | url-status =live }}</ref><ref>{{cite news|title=Skippy to the rescue|url=http://news.bbc.co.uk/2/hi/asia-pacific/3127814.stm|access-date=2 October 2011|work=BBC News|date=22 September 2003|archive-date=18 September 2010|archive-url=https://web.archive.org/web/20100918101106/http://news.bbc.co.uk/2/hi/asia-pacific/3127814.stm|url-status=live}}</ref>

There are very few records of kangaroos attacking humans without provocation; however, several such unprovoked attacks in 2004 spurred fears of a [[Medicine:Rabies|rabies]]-like disease possibly affecting the marsupials. Only two reliably documented cases of a fatality from a kangaroo attack have occurred in Australia. The first attack occurred in New South Wales in 1936 when a hunter was killed as he tried to rescue his two dogs from a heated fray.<ref>{{cite web|url=https://trove.nla.gov.au/newspaper/article/17262066|title=Kangaroo's attack causes man's death|work=Sydney Morning Herald|date=19 August 1936|access-date=12 September 2022}}</ref> The second attack was inflicted on a 77-year-old man from a domesticated kangaroo in Redmond, Western Australia in September 2022.<ref>{{cite news|url=https://www.watoday.com.au/national/western-australia/kangaroo-attacks-man-stops-paramedics-from-saving-his-life-20220912-p5bhi4.html|title=Kangaroo kills man, stops paramedics from saving his life|work=WAtoday|date=12 September 2022|access-date=12 September 2022}}</ref> Other suggested causes for erratic and dangerous kangaroo behaviour include extreme thirst and hunger. In July 2011, a male red kangaroo attacked a 94-year-old woman in her own backyard as well as her son and two police officers responding to the situation. The kangaroo was capsicum sprayed (pepper sprayed) and later put down after the attack.<ref>{{cite news|title=Rogue kangaroo attacks 94-year-old Phyllis Johnson|url=https://www.bbc.co.uk/news/world-asia-pacific-14287357|access-date=2 October 2011|work=BBC News|date=26 July 2011|archive-date=20 November 2011|archive-url=https://web.archive.org/web/20111120050621/http://www.bbc.co.uk/news/world-asia-pacific-14287357|url-status=live}}</ref><ref>{{Cite news|title=Pepper-sprayed kangaroo put down|url=http://www.abc.net.au/news/2011-07-27/pepper-sprayed-roo-put-down/2813022|access-date=2 October 2011|publisher=ABC News|date=27 July 2011|archive-date=22 September 2011|archive-url=https://web.archive.org/web/20110922123028/http://www.abc.net.au/news/2011-07-27/pepper-sprayed-roo-put-down/2813022|url-status=live}}</ref>

Kangaroos—even those that are not domesticated—<ref name=":1">{{Cite news|last=Duran|first=Paulina|date=2020-12-16|title=Kangaroos can learn to communicate with humans, researchers say|language=en|work=Reuters|url=https://www.reuters.com/article/us-australia-wildlife-kangaroo-idUSKBN28Q0I9|access-date=2020-12-16|archive-date=16 December 2020|archive-url=https://web.archive.org/web/20201216094153/https://www.reuters.com/article/us-australia-wildlife-kangaroo-idUSKBN28Q0I9|url-status=live}}</ref> can communicate with humans, according to a research study.<ref name=":1" />{{Clarification needed|reason=How do they communicate?|date=December 2023}}

=== Collisions with vehicles ===
[[File:Kangaroo Sign at Stuart Highway.jpg|thumb|upright=0.7|A "kangaroo crossing" sign on an Australian highway]]
Nine out of ten animal collisions in Australia involve kangaroos. A collision with a vehicle is capable of killing a kangaroo. Kangaroos dazzled by headlights or startled by engine noise often leap in front of cars. Since kangaroos in mid-bound can reach speeds of around 50&nbsp;km/h (31&nbsp;mph) and are relatively heavy, the force of impact can be severe. Small vehicles may be destroyed, while larger vehicles may suffer engine damage. The risk of harm or death to vehicle occupants is greatly increased if the windscreen is the point of impact. As a result, "kangaroo crossing" signs are commonplace in Australia.

Vehicles that frequent isolated roads, where roadside assistance may be scarce, are often fitted with "roo bars" to minimise damage caused by collision. Bonnet-mounted devices, designed to scare wildlife off the road with [[Physics:Ultrasound|ultrasound]] and other methods, have been devised and marketed.

If a female is the victim of a collision, animal welfare groups ask that her pouch be checked for any surviving joey, in which case it may be removed to a wildlife sanctuary or veterinary surgeon for rehabilitation. Likewise, when an adult kangaroo is injured in a collision, a vet, the RSPCA Australia or the National Parks and Wildlife Service can be consulted for instructions on proper care. In New South Wales, rehabilitation of kangaroos is carried out by volunteers from WIRES.  Council road signs often list phone numbers for callers to report injured animals.

== Emblems and popular culture ==
[[File:Coat of Arms of Australia.svg|thumb|left|upright=0.7|A kangaroo and an emu feature on the Australian coat of arms]]
The kangaroo is a recognisable symbol of Australia. The kangaroo and [[Biology:Emu|emu]] feature on the Australian coat of arms.  Kangaroos have also been featured on coins, most notably the five kangaroos on the Australian one dollar coin.  The Australian Made logo consists of a golden kangaroo in a green triangle to show that a product is grown or made in Australia.

Registered [[Social:Trademark|trademark]]s of early Australian companies using the kangaroo included Yung, Schollenberger & Co. Walla Walla Brand leather and skins (1890); Arnold V. Henn (1892) whose emblem showed a family of kangaroos playing with a skipping rope; Robert Lascelles & Co. linked the speed of the animal with its velocipedes (1896); while some overseas manufacturers, like that of "The Kangaroo" [[Engineering:Match|safety matches]] (made in Japan) of the early 1900s, also adopted the symbol. Even today, Australia's national airline, [[Company:Qantas|Qantas]], uses a bounding kangaroo for its logo.<ref name=":0">{{Citation |last1=Cozzolino |first1=Mimmo |last2=Rutherford |first2=Graeme Fysh |title=Symbols of Australia | date=2000 | page=62 | publisher=Mimmo Cozzolino | edition=20th anniversary | isbn=978-0-646-40309-0 | }}</ref>

The kangaroo appears in Rudyard Kipling's ''Just So Stories'', "The Sing-Song of Old Man Kangaroo", while the kangaroo is chased by a dingo, he gives Nqong the Big God's advice, that his legs and tail grew longest before five o'clock.<ref>{{Cite web|url=https://etc.usf.edu/lit2go/79/just-so-stories/1298/the-sing-song-of-old-man-kangaroo/|title="The Sing-Song of Old Man Kangaroo" &#124; Just So Stories &#124; Rudyard Kipling &#124; Lit2Go ETC|access-date=8 August 2021|archive-date=8 August 2021|archive-url=https://web.archive.org/web/20210808130829/https://etc.usf.edu/lit2go/79/just-so-stories/1298/the-sing-song-of-old-man-kangaroo/|url-status=live}}</ref>

The kangaroo and wallaby feature predominantly in Australian sports teams names and mascots. Examples include the Australian national rugby league team (the Kangaroos) and the Australian national rugby union team (the Wallabies). In a nation-wide competition held in 1978 for the XII Commonwealth Games by the Games Australia Foundation Limited in 1982, Hugh Edwards' design was chosen; a simplified form of six thick stripes arranged in pairs extending from along the edges of a triangular centre represent both the kangaroo in full flight, and a stylised "A" for Australia.<ref name=":0"/>

Kangaroos are well represented in films, television, books, toys and souvenirs around the world. ''Skippy the Bush Kangaroo'' was a popular 1960s Australian children's television series about a fictional pet kangaroo. Kangaroos are featured in the Rolf Harris song "Tie Me Kangaroo Down, Sport" and several Christmas carols.

== Meat ==
{{Main|Biology:Kangaroo meat}}
[[File:Kangaroo Meat.jpg|thumb|upright=0.7|Kangaroo meat on sale in Melbourne]]
The kangaroo has been a source of food for indigenous Australians for tens of thousands of years. Kangaroo meat is high in [[Biology:Protein|protein]] and low in fat (about 2%). Kangaroo meat has a high concentration of [[Chemistry:Conjugated linoleic acid|conjugated linoleic acid]] (CLA) compared with other foods, and is a rich source of vitamins and minerals.<ref name="Macro Meats Australia">{{cite web|title=Nutrition |url=http://www.macromeats.com.au/Nutrition/AmazingNutritionFacts.aspx |access-date=6 November 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131101083733/http://www.macromeats.com.au/Nutrition/AmazingNutritionFacts.aspx |archive-date=1 November 2013 }}</ref> Low fat diets rich in CLA have been studied for their potential in reducing obesity and atherosclerosis.<ref name = SMH20070926>{{Cite news|url = http://www.smh.com.au/news/environment/an-industry-thats-under-the-gun/2007/09/25/1190486311919.html?page=fullpage|title = An industry that's under the gun|date = 26 September 2007|last = Dow|first = Steve|work = The Sydney Morning Herald|access-date = 19 August 2008|archive-date = 3 July 2017|archive-url = https://web.archive.org/web/20170703024346/http://www.smh.com.au/news/environment/an-industry-thats-under-the-gun/2007/09/25/1190486311919.html?page=fullpage|url-status = live}}</ref><ref>{{cite journal |vauthors=Sinclair AJ, O'Dea K, Dunstan G, Ireland PD, Niall M |s2cid=4001525 |title=Effects on plasma lipids and fatty acid composition of very low fat diets enriched with fish or kangaroo meat |journal=Lipids |volume=22 |issue=7 |pages=523–9 |date=July 1987 |pmid=3626779 |doi=10.1007/BF02540369 }}</ref>

Kangaroo meat is sourced from wild animals and is seen by many as the best source of population control programs<ref>{{Cite web|url=https://www.daytondailynews.com/news/national/students-served-kangaroo-meat-chili-school-without-their-knowledge/xmjhutJRQeXeaHwwWaI9rO/|title=Students served kangaroo meat in chili at school without their knowledge|last=Shelby Lin Erdman|first=Cox Media Group National Content Desk|website=daytondailynews|access-date=20 February 2019|archive-date=21 February 2019|archive-url=https://web.archive.org/web/20190221000542/https://www.daytondailynews.com/news/national/students-served-kangaroo-meat-chili-school-without-their-knowledge/xmjhutJRQeXeaHwwWaI9rO/|url-status=live}}</ref> as opposed to culling them as pests where carcasses are left in paddocks. Kangaroos are harvested by licensed shooters in accordance with a code of practice and are protected by state and federal legislation.<ref>{{Cite web|url=https://news.nationalgeographic.com/2017/11/wildlife-watch-kangaroo-hunting-controversy-australia/|title=Australians Hunt Kangaroos Commercially. Does It Make Sense?|date=21 November 2017|website=National Geographic News|access-date=20 February 2019|archive-date=19 February 2019|archive-url=https://web.archive.org/web/20190219120755/https://news.nationalgeographic.com/2017/11/wildlife-watch-kangaroo-hunting-controversy-australia/|url-status=dead}}</ref><ref>{{Cite web|url=http://blogs.reuters.com/photographers-blog/2013/04/03/a-necessary-evil-the-kangaroo-cull/|archive-url=https://web.archive.org/web/20130406031042/http://blogs.reuters.com/photographers-blog/2013/04/03/a-necessary-evil-the-kangaroo-cull|url-status=dead|archive-date=6 April 2013|title=A necessary evil – the kangaroo cull|last=Gray|first=David|date=3 April 2013|website=Reuters Blogs|access-date=20 February 2019}}</ref>

Kangaroo meat is exported to many countries around the world.  However, it is not considered biblically kosher by [[Religion:Jews|Jews]] or Adventists.<ref>{{cite web|url=https://www.chabad.org/library/article_cdo/aid/4660882/jewish/Is-Kangaroo-Kosher.htm|title=Is Kangaroo Kosher?|website=Chabad.org|access-date=2021-08-08|archive-date=8 August 2021|archive-url=https://web.archive.org/web/20210808004234/https://www.chabad.org/library/article_cdo/aid/4660882/jewish/Is-Kangaroo-Kosher.htm|url-status=live}}</ref>  It is considered [[Religion:Halal|halal]] according to Muslim dietary standards, because kangaroos are herbivorous.<ref>{{cite web| url = https://www.islamweb.net/en/fatwa/87429/kangaroo-meat| title = Kangaroo meat - Islamweb - Fatwas| access-date = 30 December 2021| archive-date = 30 December 2021| archive-url = https://web.archive.org/web/20211230213758/https://www.islamweb.net/en/fatwa/87429/kangaroo-meat| url-status = live}}</ref>

== See also ==
* {{annotated link|Engineering:BionicKangaroo}}
* {{annotated link|Biology:Embryonic diapause}}
* {{annotated link|Biology:Kangaroo industry}}

== References ==
{{Reflist}}

== Further reading ==
{{refbegin|30em}}
* {{cite book |last1=McCullough |first1=Dale R. |last2=McCullough |first2=Yvette |title=Kangaroos in Outback Australia |publisher=Columbia University Press |year=2000 |isbn=978-0-231-11916-0 |ref={{harvid|McCullough|2000}}}}
* {{cite book |last1=Flannery | title=Tree Kangaroos: A Curious Natural History |publisher=Reed Books |location=Melbourne |year=1996 |isbn=978-0-7301-0492-6 |first1=Timothy Fridtjof |last2=Martin |first2=Roger }}
* {{cite book |author=Underhill D. |title=Australia's Dangerous Creatures |publisher=Reader's Digest |location=Sydney NSW |year=1993 |isbn=978-0-86438-018-0 }}
* {{cite book |first=Michael |last=Archer| title=The Kangaroo |publisher=Kevin Weldon Press |location=Sydney NSW |year=1985 |isbn=978-0-949708-22-9 }}
{{refend}}

== External links ==
{{Commons|Macropus}}
* [https://www.youtube.com/watch?v=2lCKc8tURtc Video of Kangaroo giving Birth]



[[Category:Macropods]]
[[Category:Clawed herbivores]]
[[Category:Paraphyletic groups]]

{{Sourceattribution|Kangaroo}}