Swamp wallaby

{{short description|Species of mammal}} {{Speciesbox | name = | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=Menkhorst, P. |author2=Denny, M. |author3=Ellis, M. |author4=Winter, J. |author5=Burnett, S. |author6=Lunney, D. |author7=van Weenen, J. |date=2016 |title=''Wallabia bicolor'' |volume=2016 |article-number=e.T40575A21952658 |doi=10.2305/IUCN.UK.2016-2.RLTS.T40575A21952658.en |access-date=12 November 2021}}</ref> | image = Wallabia bicolor Jenolan Caves.jpg | genus = Wallabia | parent_authority = Trouessart, 1905<ref>{{cite book|last1=Trouessart|first1=E.-L.|title=Catalogus mammalium tam viventium quam fossilium|volume=Quinquennale supplementum|date=1904|publisher=R. Friedländer & Sohn|location=Berolini|page=834|url=https://www.biodiversitylibrary.org/page/40579370}}</ref> | species = bicolor | authority = (Desmarest, 1804) | display_parents = 2 | range_map = Swamp_Wallaby_IUCN_Range.png | range_map_caption = Swamp wallaby range | synonyms ={{collapsible list |''Kangurus bicolor'' Desmarest, 1804 |''Kangurus ualabatus'' Lesson & Garnot, 1826 |''Halmaturus lessonii'' Gray, 1837 |''Halmaturus nemoralis'' Wagner, 1842 |''Macropus ualabatus'' Thomas & Dollman, 1909 }} }} The '''swamp wallaby''' ('''''Wallabia bicolor''''') is a small macropod marsupial of eastern Australia.<ref name=Merchant1995>{{cite book | author = Merchant, J. C. | year = 1995 | editor = Strahan, Ronald| title = Mammals of Australia | edition = Revised | publisher = Reed New Holland Publishers | location = Sydney | page = 409}}</ref> This wallaby is also commonly known as the '''black wallaby''', with other names including '''black-tailed wallaby''', '''fern wallaby''', '''black pademelon''', '''stinker''' (in Queensland), and '''black stinker''' (in New South Wales) on account of its characteristic swampy odour.

The swamp wallaby is the only living member of the genus '''''Wallabia'''''.<ref name=Merchant1983>{{cite book | author = Merchant, J. C. | year = 1983 | editor = Strahan, Ronald| title = The Australian Museum Complete Book of Australian Mammals, The National Photographic Index of Australian Wildlife | edition = Corrected 1991 reprint | publisher = Cornstalk Publishing | location = Australia | pages = 261–262 | isbn = 0-207-14454-0}}</ref>

==Etymology== Historic names for the swamp wallaby include '''Aroe kangaroo'''. The swamp wallaby is known as ''banggarai'' in the Dharawal language.<ref>{{Cite web|url=https://dharug.dalang.com.au/language/view_word/1855|title=Dharug and Dharawal Resources}}</ref>

==Habitat and distribution== The swamp wallaby is found from the northernmost areas of Cape York Peninsula in Queensland, down the entire east coast and around to western Victoria and south-eastern South Australia, where it has greatly expanded its distribution over the past four decades. Advances in rabbit control appear to have resulted in extension of the swamp wallaby's distribution, which has expanded since the time of European settlement.<ref>{{cite journal |last1=Cooke |first1=B. D. |title=Swamp wallaby (Wallabia bicolor) distribution has dramatically increased following sustained biological control of rabbits |journal=Australian Mammalogy |date=2020 |volume=42 |issue=3 |page=321 |doi=10.1071/AM19037 |url=https://www.publish.csiro.au/am/AM19037 |access-date=31 October 2024|url-access=subscription }}</ref>

It inhabits thick undergrowth in forests and woodlands, or shelters during the day in thick grass or ferns, emerging at night to feed. They have been found to inhabit diverse habitats such as open farmland, mallee woodland, and sand-hills.<ref>{{cite journal |last1=Cooke |first1=B. D. |title=Swamp wallaby (Wallabia bicolor) distribution has dramatically increased following sustained biological control of rabbits |journal=Australian Mammalogy |date=2020 |volume=42 |issue=3 |page=321 |doi=10.1071/AM19037 |url=https://www.publish.csiro.au/am/AM19037 |access-date=31 October 2024|url-access=subscription }}</ref> Brigalow scrub in Queensland is a particularly favoured habitat.<ref name=Merchant1983/>

==Description== The species name ''bicolor'' comes from the distinct colouring variation, with the typical grey coat of the macropods varied with a dark brown to black region on the back, and light yellow to rufous orange on the chest. A light coloured cheek stripe is usually present, and extremities of the body generally show a darker colouring, except for the tip of the tail, which is often white.<ref name=Merchant1995/>

The swamp wallaby also has a rare 'golden' morph, found on the North and South Stradbroke islands and adjacent mainland. It is a yellow color with a white muzzle. The nose and paws could be pink or black.<ref>{{Cite web |last=Teideman |first=Jess |date=2019-01-06 |title=Golden swamp wallaby |url=https://www.australiangeographic.com.au/archive/reader-photos/2019/01/golden-swamp-wallaby/ |access-date=2024-11-26 |website=Australian Geographic |language=en-US}}</ref>

The gait differs from other wallabies, with the swamp wallaby carrying its head low and its tail out straight.<ref name="Merchant1983" />

The average length is {{cvt|76|cm}} for males, and {{cvt|70|cm}} for females (excluding the tail). The tail in both sexes is approximately equal in length to the rest of the body. Average weight for males is {{cvt|17|kg}}, females averaging {{cvt|13|kg}}.<ref name=Merchant1983/>

The swamp wallaby has seven carpal bones in the wrist (humans have eight).<ref>{{Cite web|url=https://kmccready.wordpress.com/2014/07/03/carpals-of-swamp-wallaby-wallabia-bicolor/|title = Carpals of Swamp Wallaby – Wallabia bicolor|date = 3 July 2014}}</ref>

==Reproduction== The swamp wallaby becomes reproductively fertile between 15 and 18 months of age, and can breed throughout the year. Gestation is from 33 to 38 days, leading to a single young. The young is carried in the pouch for 8 to 9 months, but will continue to suckle until about 15 months.

The swamp wallaby exhibits an unusual form of embryonic diapause, differing from other marsupials in having its gestation period longer than its oestrous cycle.<ref name="Merchant1983" /> This timing makes it possible for swamp wallaby females to overlap two pregnancies, gestating both an embryo and a fetus at the same time. The swamp wallaby ovulates, mates, conceives and forms a new embryo one to two days before the birth of their full-term fetus. Consequently, females are continuously pregnant throughout their reproductive life.<ref>{{Cite web|url=https://www.sciencedaily.com/releases/2020/03/200302153611.htm|title=Swamp wallabies conceive new embryo before birth -- a unique reproductive strategy|website=ScienceDaily|language=en|access-date=2020-03-03}}</ref>

The swamp wallaby is notable for having a distinct sex-chromosome system from most other Theria (the subclass that includes marsupials and placental mammals). Females are characterized by the XX pair typical of therians, but males have one X chromosome and two non-sequence homology Y chromosomes. This system is thought to arise from a series of chromosomal fusions over the last 6 million years.<ref>{{cite journal |last1=Toder |first1=R |last2=O'Neill |first2=R J |last3=Wienberg |first3=K |last4=O'Brien |first4=P C |last5=Voullaire |first5=L |last6=Marshall-Graves |first6=J A |title=Comparative chromosome painting between two marsupials: origins of an XX/XY1Y2 sex chromosome system |journal=Mamm Genome |date=June 1997 |volume=8 |issue=6 |pages=418–22 |doi=10.1007/s003359900459 |pmid=9166586 |s2cid=12515691 }}</ref>

thumb|left|A swamp wallaby feeding on leaves

==Feeding== The swamp wallaby is typically a solitary animal, but often aggregates into groups when feeding.<ref name=Merchant1995/> It will eat a wide range of food plants, depending on availability, including shrubs, pasture, agricultural crops, and native and exotic vegetation. It appears to be able to tolerate a variety of plants poisonous to many other animals, including brackens, hemlock and lantana.<ref name=Merchant1983/>

The ideal diet appears to involve browsing on shrubs and bushes, rather than grazing on grasses. This is unusual in wallabies and other macropods, which typically prefer grazing. Tooth structure reflects this preference for browsing, with the shape of the molars differing from other wallabies. The fourth premolar is retained through life, and is shaped for cutting through coarse plant material.<ref name=Merchant1983/>

There is evidence that the swamp wallaby is an opportunist taking advantage of food sources when they become available, such as fungi, bark and algae. There is also one reported case of the consumption of carrion.<ref>{{cite journal|last1=Fitzsimons|first1=James A.|year=2016|title=Carrion consumption by the swamp wallaby (Wallabia bicolor)|journal=Australian Mammalogy|volume=39|page=105|doi=10.1071/AM16017}}</ref>

==Taxonomy==

Several physical and behavioral characteristics make the swamp wallaby different enough from other wallabies that it is placed apart in its own genus, ''Wallabia''.<ref name=msw3>{{MSW3 Groves|pages=70|id=11000314}}</ref><ref name=Merchant1995/> However, genetic evidence demonstrates that ''Wallabia'' is embedded within the large genus ''Macropus'', necessitating reclassification of this species in the future.<ref>{{cite journal |last1=Dodt |first1=William G. |last2=Gallus |first2=Susanne |last3=Phillips |first3=Matthew J. |last4=Nilsson |first4=Maria A. |title=Resolving kangaroo phylogeny and overcoming retrotransposon ascertainment bias |journal=Scientific Reports |date=1 December 2017 |volume=7 |issue=1 |article-number=16811 |doi=10.1038/s41598-017-16148-0 |pmid=29196678 |pmc=5711953 |bibcode=2017NatSR...716811D }}</ref>

== Threats == Anthropogenic actions, such as the increase in roads through swamp wallaby habitats, are a threat to their survival. They are frequently seen near the side of roads, leading to a larger number becoming roadkill.<ref>{{Cite journal|last=Osawa|first=R|date=1989|title=Road-Kills of the Swamp Wallaby, Wallabia-Bicolor, on North-Stradbroke-Island, Southeast Queensland|url=http://www.publish.csiro.au/?paper=WR9890095|journal=Wildlife Research|language=en|volume=16|issue=1|page=95|doi=10.1071/WR9890095|bibcode=1989WildR..16...95O|issn=1035-3712|url-access=subscription}}</ref>

Other sources of threat for the swamp wallaby are their predators, which include dingoes, eagles and wild dogs.<ref>{{Cite journal|last1=Davis|first1=Naomi E. |last2=Forsyth |first2=David M. |last3=Triggs |first3=Barbara |last4=Pascoe |first4=Charlie |last5=Benshemesh |first5=Joe |last6=Robley |first6=Alan |last7=Lawrence |first7=Jenny |last8=Ritchie |first8=Euan G. |last9=Nimmo |first9=Dale G. |last10=Lumsden |first10=Lindy F. |date=2015-03-19 |editor-last=Crowther |editor-first=Mathew S. |title=Interspecific and Geographic Variation in the Diets of Sympatric Carnivores: Dingoes/Wild Dogs and Red Foxes in South-Eastern Australia |journal=PLOS ONE |language=en |volume=10 |issue=3 |article-number=e0120975 |doi=10.1371/journal.pone.0120975|issn=1932-6203 |pmc=4366095 |pmid=25790230 |bibcode=2015PLoSO..1020975D |doi-access=free}}</ref>

== References == {{Reflist}}

==External links== {{Wikispecies|Wallabia bicolor}} {{Commons|Wallabia bicolor}} *{{cite web |title=''Wallabia'' Trouessart, 1905 |publisher=Atlas of Living Australia |url=https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/f33c3347-515b-4d9f-a2d7-9aba91f42435}} *[https://web.archive.org/web/20060108155412/http://faunanet.gov.au/wos/factfile.cfm?Fact_ID=305 Australian Museum]

Category:Macropods Category:Marsupials of Australia Category:Mammals of South Australia Category:Mammals of New South Wales Category:Mammals of Queensland Category:Mammals of Victoria (state) Category:Least concern biota of Australia Category:Mammals described in 1804 Category:Taxa named by Anselme Gaëtan Desmarest