View source for Opossum

{{short description|Family of mammals}}
{{for multi|the Australasian marsupials known as "possums"|Phalangeriformes|other uses|Opossum (disambiguation)}}
{{Automatic taxobox
| name = Didelphidae<ref name=msw3>{{MSW3 Gardner|pages=3–18}}</ref>
| fossil_range = {{Fossil range|Early Miocene | Recent}}<ref>{{cite journal|author= Goin, Francisco |author2=Abello, Alejandra |author3=Bellosi, Eduardo |author4=Kay, Richard |author5=Madden, Richard |author6=Carlini, Alfredo |title= Los Metatheria sudamericanos de comienzos del Neógeno (Mioceno Temprano, Edad-mamífero Colhuehuapense). Parte I: Introducción, Didelphimorphia y Sparassodonta |journal=Ameghiniana|volume=44|issue=1|pages=29–71|year=2007|url=http://www.scielo.org.ar/scielo.php?pid=S0002-70142007000100003&script=sci_abstract}}</ref>
| image = Didelphis virginiana with young.JPG
| image_caption = [[Virginia opossum]], ''[[Didelphis]] virginiana'', the only U.S. and Canadian species (mother with nine young)
| display_parents = 2
| parent_authority = [[Theodore Nicholas Gill|Gill]], 1872
| type_genus = ''[[Didelphis]]''
| type_genus_authority = [[Carl Linnaeus|Linnaeus]], 1758
| taxon = Didelphidae
| authority = [[John Edward Gray|J. E. Gray]], 1821
| diversity = 126 species
| subdivision_ranks = [[Genera]]
| subdivision = [[#Classification|See text]]
}}

'''Opossums''' ({{IPAc-en|ə|ˈ|p|ɒ|s|ə|m|z}}) are members of the [[marsupial]] order '''Didelphimorphia''' ({{IPAc-en|d|aɪ|ˌ|d|ɛ|l|f|ᵻ|ˈ|m|ɔːr|f|i|ə}}) [[Endemism|endemic]] to the [[Americas]]. The largest order of marsupials in the [[Western Hemisphere]], it comprises 126 species in 18 [[Genus|genera]]. Opossums originated in [[South America]] and entered [[North America]] in the [[Great American Interchange]] following the connection of North and South America in the late [[Cenozoic]].

The [[Virginia opossum]] is the only species found in the United States and Canada. It is often simply referred to as an '''opossum'''; in North America, it is commonly referred to as a '''possum'''<ref name="NationalGeographic">{{cite magazine |url=https://www.nationalgeographic.com/animals/mammals/group/opossums/ |archive-url=https://web.archive.org/web/20170221153623/http://www.nationalgeographic.com/animals/mammals/group/opossums/ |url-status=dead |archive-date=February 21, 2017 |title=Opossums |magazine=[[National Geographic]] |access-date=September 21, 2018}}</ref> ({{IPAc-en|ˈ|p|ɒ|s|əm}}; sometimes rendered as ''{{'}}possum'' in written form to indicate the dropped "o"). The [[Australasian realm|Australasian]] arboreal marsupials of suborder [[Phalangeriformes]] are also called possums because of their resemblance to opossums, but they belong to a different order. The opossum is typically a nonaggressive animal and almost never carries the virus that causes [[rabies]].<ref>{{cite web |title=Rabies: A Forgotten Killer Greatest Risk from Wildlife, Especially Bats |url=https://www.cdc.gov/vitalsigns/rabies/pdf/vs-0612-wildlife-rabies-h.pdf |publisher=CDC}}</ref>

== Etymology ==
The word ''opossum'' is derived from the [[Powhatan language]] and was first recorded between 1607 and 1611 by [[John Smith (explorer)|John Smith]] (as ''opassom'') and [[William Strachey]] (as ''aposoum'').<ref>{{cite book |last=Mithun |first=Marianne |date=2001 |title=The Languages of Native North America |publisher=Cambridge University Press |page=332 |isbn=978-0-521-29875-9 | url = https://books.google.com/books?id=ALnf3s2m7PkC}}</ref> ''Possum'' was first recorded in 1613. Both men encountered the language at the English settlement of [[Jamestown, Virginia]], which Smith helped to found and where Strachey later served as its first secretary.<ref name="Siebert">{{cite encyclopedia | last=Siebert | first=Frank T. Jr. |editor-last=Crawford |editor-first=James Mack |date=1975 |encyclopedia=Studies in Southeastern Indian Languages |title=Resurrecting Virginia Algonquian from the Dead: The Reconstituted and Historical Phonology of Powhatan |publisher=University of Georgia Press}}</ref> Strachey's notes describe the opossum as a "beast in bigness of a pig and in taste alike," while Smith recorded it "hath an head like a swine ... tail like a rat ... of the bigness of a cat."<ref name="Siebert" /> The Powhatan word ultimately derives from a [[Proto-Algonquian language|Proto-Algonquian]] word (''*wa·p-aʔθemwa'') meaning "white dog or dog-like beast."<ref name="Siebert" />

Following the arrival of Europeans in [[Australia]], the term ''possum'' was borrowed to describe distantly related [[Australidelphia|Australian marsupials]] of the suborder [[Phalangeriformes]],<ref>{{cite dictionary | title = The American Heritage Dictionary of the English Language, Fifth Edition | year = 2014 | entry = possum | publisher = Houghton Mifflin Harcourt | url = http://ahdictionary.com/word/search.html?q=possum | access-date = 12 July 2014}}</ref> which are more closely related to other Australian marsupials such as kangaroos.

Didelphimorphia comes from the [[Ancient Greek]] words for "two" (''di'') and "wombs" (''delphus'').<ref>{{cite dictionary|title=Wordnik|url=https://www.wordnik.com/words/Didelphimorphia|entry=Didelphimorphia|access-date=14 June 2024}}</ref>

== Evolution ==

Opossums are often considered to be "[[living fossil]]s",<ref name = "Krause"/> and as a result they are often used to approximate the ancestral [[theria]]n condition in comparative studies.<ref name = "Krause"/><ref>{{cite journal |last1=Crompton |first1=A. W. |last2=Hiiemae |first2=Karen |title=Molar occlusion and mandibular movements during occlusion in the American opossum, ''Didelphis marsupialis'' L. |journal=Zoological Journal of the Linnean Society |date=February 1970 |volume=49 |issue=1 |pages=21–47 |doi=10.1111/j.1096-3642.1970.tb00728.x|doi-access=free }}</ref> But the oldest opossum fossils are from a more recent epoch, the early [[Miocene]] (roughly 20&nbsp;million years ago).<ref>{{cite journal|author=Goin, Francisco|author2=Abello, Alejandra|author3=Bellosi, Eduardo|author4=Kay, Richard|author5=Madden, Richard|author6=Carlini, Alfredo|year=2007|title=Los Metatheria sudamericanos de comienzos del ta|url=http://www.scielo.org.ar/scielo.php?pid=S0002-70142007000100003&script=sci_abstract|journal=Ameghiniana|volume=44|issue=1|pages=29–71}}</ref> The last common ancestor of all living opossums dates approximately to the [[Oligocene]]-Miocene boundary (23&nbsp;million years ago) and is at most no older than Oligocene in age.<ref name=Jansa2014>{{Cite journal|last1=Jansa|first1=Sharon A.|last2=Barker|first2=F. Keith|last3=Voss|first3=Robert S.|title=The Early Diversification History of Didelphid Marsupials: A Window into South America's "splendid Isolation"|date=March 2014|journal=Evolution|language=en|volume=68|issue=3|pages=684–695|doi=10.1111/evo.12290|pmid=24125654|s2cid=10274949}}</ref><ref name="BeckTaglioretti" /> Many extinct metatherians, such as ''[[Alphadon]]'', ''[[Peradectes]]'', ''[[Herpetotherium]]'', and ''[[Pucadelphys]]'', were once considered to be early opossums, but it has since been recognized that this was solely on the basis of [[plesiomorphies]]; they are now considered to belong to older branches of [[Metatheria]] that are only distantly related to modern opossums.

Opossums probably originated in the [[Amazon rainforest|Amazonia]] region of northern South America, where they began their initial diversification.<ref>{{Cite journal |last1=Castro |first1=Mariela C. |last2=Dahur |first2=Murilo J. |last3=Ferreira |first3=Gabriel S. |date=2021-09-01 |title=Amazonia as the Origin and Diversification Area of Didelphidae (Mammalia: Metatheria), and a Review of the Fossil Record of the Clade |journal=Journal of Mammalian Evolution |language=en |volume=28 |issue=3 |pages=583–598 |doi=10.1007/s10914-021-09548-7 |s2cid=237866763 |issn=1573-7055|doi-access=free }}</ref> They were minor components of South American mammal faunas until the late Miocene, when they began to diversify rapidly.<ref name=Jansa2014/> Before that time, the [[ecological niches]] presently occupied by opossums were occupied by other groups of metatherians such as [[paucituberculata]]ns<ref name = Engelman2017>{{cite journal |last1=Engelman |first1=Russell K. |last2=Anaya |first2=Federico |last3=Croft |first3=Darin A. |title=New palaeothentid marsupials (Paucituberculata) from the middle Miocene of Quebrada Honda, Bolivia, and their implications for the palaeoecology, decline and extinction of the Palaeothentoidea |journal=Journal of Systematic Palaeontology |date=9 November 2016 |volume=15 |issue=10 |pages=787–820 |doi=10.1080/14772019.2016.1240112|s2cid=88758358 |url=https://figshare.com/articles/dataset/New_palaeothentid_marsupials_Paucituberculata_from_the_middle_Miocene_of_Quebrada_Honda_Bolivia_and_their_implications_for_the_palaeoecology_decline_and_extinction_of_the_Palaeothentoidea/4216506 |url-access=subscription }}</ref> and [[sparassodonts]].<ref name="BeckTaglioretti" /><ref name=EngelmanCroft2014>{{cite journal |last1=Engelman |first1=Russell K. |last2=Croft |first2=Darin A. |title=A new species of small-bodied sparassodont (Mammalia, Metatheria) from the middle Miocene locality of Quebrada Honda, Bolivia |journal=Journal of Vertebrate Paleontology |date=6 May 2014 |volume=34 |issue=3 |pages=672–688 |doi=10.1080/02724634.2013.827118|bibcode=2014JVPal..34..672E |s2cid=84680371 |url=https://figshare.com/articles/dataset/A_new_species_of_small_bodied_sparassodont_Mammalia_Metatheria_from_the_middle_Miocene_locality_of_Quebrada_Honda_Bolivia/1017004 |doi-access=free }}</ref><ref name=Engelman2018>{{cite journal |last1=Engelman |first1=Russell K. |last2=Anaya |first2=Federico |last3=Croft |first3=Darin A. |title=''Australogale leptognathus'', gen. et sp. nov., a Second Species of Small Sparassodont (Mammalia: Metatheria) from the Middle Miocene Locality of Quebrada Honda, Bolivia |journal=Journal of Mammalian Evolution |date=27 June 2018 |volume=27 |issue=1 |pages=37–54 |doi=10.1007/s10914-018-9443-z|s2cid=49473591 }}</ref>
Large opossums like ''[[Didelphis]]'' show a pattern of gradually increasing in size over geologic time as [[sparassodont]] diversity declined.<ref name=EngelmanCroft2014/><ref name=Engelman2018/> Several groups of opossums, including ''Thylophorops'', ''Thylatheridium'', ''Hyperdidelphys'', and sparassocynids developed carnivorous adaptations during the late Miocene-[[Pliocene]], before the arrival of [[carnivorans]] in South America. Most of these groups, with the exception of ''[[Lutreolina]]'', are now extinct.<ref name="hyperdidelphys" /> It has been suggested that the size and shape of the ancestral didelphid's jaw would most closely match that of the modern ''Marmosa'' genus.<ref>{{cite journal |last1= das Chagas Silva-Neto|first1=Francisco |last2=Pavan |first2= Silvia E.|last3=Astúa |first3=Diego |date= 26 June 2023|title=Evolution, divergence, and convergence in the mandibles of opossums (Didelphidae, Didelphimorphia). |url= |journal=Current Zoology |volume= 70|issue= 4|pages= 488–504 |doi=10.1093/cz/zoad027 |access-date=|doi-access=free |pmid=39176066 |pmc=11336674 }}</ref>

== Characteristics ==
[[File:Monodelphis domestica skeleton - ZooKeys 465-10.png|thumb|Skeleton of the [[gray short-tailed opossum]] (''Monodelphis domestica'')]]
Didelphimorphs are small to medium-sized marsupials that grow to the size of a house cat. They tend to be semi-[[arboreal]] [[omnivore]]s, although there are many exceptions. Most members of this order have long [[snout]]s, a narrow [[Cranium|braincase]], and a prominent [[sagittal crest]]. The [[dental formula]] is: {{DentalFormula|upper=5.1.3.4|lower=4.1.3.4|total=50}} teeth. By [[mammal]]ian standards, this is an unusually full jaw. The incisors are very small, the canines large, and the molars are [[Dental anatomy#Cusp|tricuspid]].

Didelphimorphs have a [[plantigrade]] stance (feet flat on the ground) and the hind [[Foot|feet]] have an [[Thumb|opposable digit]] with no [[claw]]. Like some [[New World monkey]]s, some opossums have [[Prehensility|prehensile tails]]. Like most marsupials, many females have a pouch. The tail and parts of the feet bear [[scute]]s. The [[stomach]] is simple, with a small [[cecum]].<ref name = "Krause"/> Like most marsupials, the male opossum has a forked [[penis]] bearing twin [[Glans penis|glande]]s.<ref>{{cite journal|doi=10.1515/mamm.1997.61.2.161|url=https://www.researchgate.net/publication/240754313 |title=Penis morphology as a distinctive character of the murine opossum group (Marsupialia Didelphidae): A preliminary report |journal=Mammalia |volume=61 |issue=2 |year=1997 |last1=Martinelli |first1=P.M. |last2=Nogueira |first2=J.C. |s2cid=84674547 }}</ref><ref>{{cite journal|url=http://ctcusp.org/pdf/references2013/2013_37.pdf |pmid=23362127|year=2013|last1=De Barros|first1=M. A.|title=Marsupial morphology of reproduction: South America opossum male model|journal=Microscopy Research and Technique|volume=76|issue=4|pages=388–97|last2=Panattoni Martins|first2=J. F.|last3=Samoto|first3=V. Y.|last4=Oliveira|first4=V. C.|last5=Gonçalves|first5=N.|last6=Mançanares|first6=C. A.|last7=Vidane|first7=A.|last8=Carvalho|first8=A. F.|last9=Ambrósio|first9=C. E.|last10=Miglino|first10=M. A.|doi=10.1002/jemt.22178|s2cid=27200317}}</ref><ref name="Krause">Krause, William J.; Krause, Winifred A. (2006).[https://web.missouri.edu/~krausew/Histology/Home_files/opossum.pdf  ''The Opossum: Its Amazing Story''] {{webarchive|url=https://web.archive.org/web/20121211214644/https://web.missouri.edu/~krausew/Histology/Home_files/opossum.pdf |date=2012-12-11 }}. Department of Pathology and Anatomical Sciences, School of Medicine, University of Missouri, Columbia, Missouri. p. 39</ref>

Although all living opossums are essentially opportunistic [[omnivores]], different species vary in the amount of meat and vegetation they include in their diet. Members of the [[Caluromyinae]] are essentially [[frugivorous]]; whereas the [[lutrine opossum]] and [[Patagonian opossum]] primarily feed on other animals.<ref>{{cite book|last1=Vieira|first1=Emerson R.|last2=De Moraes|first2=D. Astua|publisher=Csiro Publishing|year= 2003|isbn=978-0-643-06634-2|title=Predators with Pouches: the biology of carnivorous marsupials|pages=267–280 |chapter=Carnivory and insectivory in Neotropical marsupials}}</ref> The [[water opossum]] or yapok (''Chironectes minimus'') is particularly unusual, as it is the only living semi-aquatic marsupial, using its webbed hindlimbs to dive in search of freshwater mollusks and crayfish.<ref>{{cite journal|title=''Chironectes minimus''|first=Larry G.|last=Marshall|journal=[[Mammalian Species]]|year=1978|volume=109|pages=1–6|doi=10.2307/3504051|issue=99|jstor=3504051|doi-access=free}}</ref> The extinct ''[[Thylophorops]]'', the largest known opossum at {{Cvt|4-7|kg}}, was a macropredator.<ref name="Goin 2009 35–46">{{cite journal|title=A new large didelphid of the genus ''Thylophorops'' (Mammalia: Didelphimorphia: Didelphidae), from the late Tertiary of the Pampean Region (Argentina)|first=Francisco J.|last=Goin|author2=Natalia Zimicz|author3=Martin de los Reyes|author4=Leopoldo Soibelzon|url=http://biostor.org/reference/19000|journal=[[Zootaxa]]|year=2009|volume=2005|pages=35–46|doi=10.11646/zootaxa.2005.1.3|hdl=11336/67625|hdl-access=free|archive-date=2013-12-17|access-date=2013-12-17|archive-url=https://web.archive.org/web/20131217052732/http://biostor.org/reference/19000|url-status=dead}}</ref><ref>{{cite journal|doi=10.1007/s10914-011-9175-9|title=The Evolution of the Cenozoic Terrestrial Mammalian Predator Guild in South America: Competition or Replacement?|journal=Journal of Mammalian Evolution|volume=20|pages=3–21|year=2011|last1=Prevosti|first1=Francisco J.|last2=Forasiepi|first2=Analía|last3=Zimicz|first3=Natalia|s2cid=15751319|hdl=11336/2663|hdl-access=free}}</ref><ref>{{cite journal|doi=10.1080/08912963.2015.1089868|title=Mammalian predator–prey relationships and reoccupation of burrows in the Pliocene of the Pampean Region (Argentina): New ichnological and taphonomic evidence|journal=Historical Biology|volume=28|issue=8|pages=1026–1040|year=2015|last1=Cenizo|first1=Marcos|last2=Soibelzon|first2=Esteban|last3=Magnussen Saffer|first3=Mariano|s2cid=83862150}}</ref> Most opossums are [[scansorial]], well-adapted to life in the trees or on the ground, but members of the [[Caluromyinae]] and [[Glironia|Glironiinae]] are primarily arboreal, whereas species of ''[[Metachirus]]'', ''[[Monodelphis]]'', and to a lesser degree ''[[Didelphis]]'' show adaptations for life on the ground.<ref>{{cite journal|title=Phylogenetic analysis of postcranial skeletal morphology in didelphid marsupials|first=David A.|last=Flores|journal=[[Bulletin of the American Museum of Natural History]]|year=2009|volume=320|pages=1–81|doi=10.1206/320.1|hdl=2246/5953|s2cid=54177473|hdl-access=free}}</ref> ''[[Metachirus nudicaudatus]]'', found in the upper [[Amazon basin]], consumes fruit seeds, small [[vertebrate]] creatures like birds and reptiles and [[invertebrate]]s like [[crayfish]] and [[snail]]s, but seems to be mainly [[insectivorous]].<ref>{{cite book |last1=Gardner |first1=Alfred |title=Mammals of South America Volume 1 |publisher=University of Chicago Press |page=34}}</ref>

[[File:Opossum (Mar 2021).jpg|thumb|Virginia opossum on top of a fence]]

=== Reproduction and life cycle ===
{{further|Marsupial#Reproductive system}}

As marsupials, female opossums have a reproductive system that includes a bifurcated [[vagina]] and a divided [[uterus]]; many have a [[Pouch (marsupial)|pouch]].<ref>Campbell, N. & Reece, J. (2005) ''Biology''. Pearson Education Inc.</ref> The average estrous cycle of the [[Virginia opossum]] is about 28 days.<ref name="Opossum Society of the United States">[http://www.opossumsocietyus.org/opossum_reproduction_and_life_cycle.htm Reproduction – Life Cycle]. opossumsocietyus.org.</ref>  Opossums do possess a [[placenta]],<ref name=Enders2005>{{cite journal |author1=Enders, A.C.  |author2=Enders, R.K.  |name-list-style=amp | year = 2005 | title = The placenta of the four-eyed opossum (''Philander opossum'') | journal = The Anatomical Record | volume = 165 | issue = 3 | pages = 431–439 | doi = 10.1002/ar.1091650311|pmid=5346723  |s2cid=85011250 }}</ref> but it is short-lived, simple in structure, and, unlike that of placental mammals, not fully functional.<ref name=Krause1985>{{cite journal |author1=Krause, W.J.  |author2=Cutts, H.  |name-list-style=amp | year = 1985 | title = Placentation in the Opossum, ''Didelphis virginiana'' | journal = Acta Anatomica | volume = 123 | issue = 3 | pages = 156–171 | doi = 10.1159/000146058 | pmid = 4061035}}</ref> The young are therefore born at a very early stage, although the [[gestation]] period is similar to that of many other small marsupials, at only 12 to 14 days.<ref name=EoM>{{cite book |editor= Macdonald, D. |author= O'Connell, Margaret A. |year= 1984 |title= The Encyclopedia of Mammals |publisher= Facts on File |location= New York |pages= [https://archive.org/details/encyclopediaofma00mals_0/page/830 830–837] |isbn= 978-0-87196-871-5 |url-access= registration |url= https://archive.org/details/encyclopediaofma00mals_0/page/830 }}</ref> They give birth to litters of up to 20 young.<ref>{{cite web |title=Opossums {{!}} National Geographic |url=https://www.nationalgeographic.com/animals/mammals/group/opossums/ |archive-url=https://web.archive.org/web/20170221153623/http://www.nationalgeographic.com/animals/mammals/group/opossums/ |url-status=dead |archive-date=February 21, 2017 |website=Animals |language=en |date=11 November 2010}}</ref> Once born, the offspring must find their way into the marsupium, if present, to hold on to and nurse from a teat. Baby opossums, like their Australian cousins, are called joeys.<ref>{{cite journal|pmid=25266360|year=2015|last1=Mellor|first1=D. J.|title=Survival implications of the development of behavioral responsiveness and awareness in different groups of mammalian young|journal=New Zealand Veterinary Journal|volume=63|issue=3|pages=131–40|last2=Lentle|first2=R. G.|doi=10.1080/00480169.2014.969349|s2cid=24045688}}</ref> Female opossums often give birth to very large numbers of young, most of which fail to attach to a [[teat]], although as many as 13 young can attach,<ref name=smithsonian /> and therefore survive, depending on species. The young are [[Weaning|weaned]] between 70 and 125 days, when they detach from the teat and leave the pouch. The opossum lifespan is unusually short for a mammal of its size, usually only one to two years in the wild and as long as four or more years in captivity. [[Senescence]] is rapid.<ref>[http://www.opossum.org/facts.htm Opossum Facts]. opossum.org.</ref>
Opossums are moderately [[Sexual dimorphism|sexually dimorphic]] with males usually being larger, heavier, and having larger [[Canine tooth|canines]] than females.<ref name=smithsonian>[http://www.mnh.si.edu/mna/image_info.cfm?species_id=65 Virginia Opossum. ''Didelphis virginiana'']. Smithsonian National Museum of Natural History.</ref> The largest difference between the opossum and non-marsupial mammals is the bifurcated penis of the male and bifurcated vagina of the female (the source of the term ''didelphimorph'', from the Greek ''didelphys'', meaning "double-wombed").<ref>{{cite web|title=Possum Hunt|url=http://projects.scsc.k12.ar.us/index.php?page=possum-hunt|url-status=dead|archive-url=https://web.archive.org/web/20131110190430/http://projects.scsc.k12.ar.us/index.php?page=possum-hunt|archive-date=2013-11-10}}</ref> Opossum spermatozoa exhibit sperm-pairing, forming conjugate pairs in the [[epididymis]]. This may ensure that [[flagella]] movement can be accurately coordinated for maximal [[motility]]. Conjugate pairs dissociate into separate spermatozoa before fertilization.<ref>{{cite journal
 |author= Moore, H.D.
 |title= Gamete biology of the new world marsupial, the grey short-tailed opossum, monodelphis domestica
 |journal=Reproduction, Fertility, and Development
 |volume= 8
 |issue=4
 |pages=605–15
 |year=1996
 |doi= 10.1071/RD9960605
|pmid= 8870084
 }}</ref>

=== Behavior ===
[[File:Opossum2.jpg|left|thumb|Virginia opossum [[apparent death|feigning death]], or "playing possum"]]

Opossums are usually solitary and nomadic, staying in one area as long as food and water are easily available. Some families will group together in ready-made burrows or even under houses. Though they will temporarily occupy abandoned burrows, they do not dig or put much effort into building their own. As nocturnal animals, they favor dark, secure areas. These areas may be below ground or above.<ref>{{cite journal|author=Hamilton, W. J. Jr. |year=1958|title= Life history and economic relations of the opossum (''Didelphis marsupialis virginiana'') in New York State|journal= Cornell Univ. Agric. Exp. Sta. Memoirs |volume=354|pages=1–48}}</ref><ref>{{Cite web|url=http://wdfw.wa.gov/living/opossums.html|title=Opossums – Living with Wildlife {{!}} Washington Department of Fish & Wildlife|website=wdfw.wa.gov|access-date=2017-05-14}}</ref>

[[File:Baby opossum.jpg|right|thumb|Juvenile Virginia opossum hissing defensively]]
When threatened or harmed, they will "[[Apparent death|play possum]]", mimicking the appearance and smell of a sick or dead animal. This physiological response is involuntary (like fainting), rather than a conscious act.  In the case of baby opossums, however, the brain does not always react this way at the appropriate moment, and therefore they often fail to "play dead" when threatened. When an opossum is "playing possum", the animal's lips are drawn back, the teeth are bared, saliva foams around the mouth, the eyes close or half-close, and a foul-smelling fluid is secreted from the [[anal glands]]. The stiff, curled form can be prodded, turned over, and even carried away without reaction. The animal will typically regain consciousness after a period of a few minutes to four hours, a process that begins with a slight twitching of the ears.<ref>[http://www.opossumsocietyus.org/injured_opossum.html Found an Orphaned or injured Opossum?]. Opossumsocietyus.org. Retrieved on 2012-05-03.</ref>

Some species of opossums have [[prehensile tail]]s, although dangling by the tail is more common among juveniles. An opossum may also use its tail as a brace and a fifth limb when climbing. The tail is occasionally used as a grip to carry bunches of leaves or bedding materials to the nest.<ref name="GonzálezClaramunt2000">{{cite journal|last1=González|first1=E.M.|last2=Claramunt|first2=S.|title=Behaviors of captive short-tailed Opossums, ''Monodelphis dimidiata'' (Wagner, 1847) (Didelphimorphia, Didelphidae)|journal=Mammalia|volume=64|issue=3|year=2000|pages=271–286 |doi=10.1515/mamm.2000.64.3.271|s2cid=84782113}}</ref> A mother will sometimes carry her young upon her back, where they will cling tightly even when she is climbing or running.

Threatened opossums (especially males) will growl deeply, raising their pitch as the threat becomes more urgent. Males make a clicking "smack" noise out of the side of their mouths as they wander in search of a mate, and females will sometimes repeat the sound in return. When separated or distressed, baby opossums will make a sneezing noise to signal their mother.  The mother in return makes a clicking sound and waits for the baby to find her. If threatened, the baby will open its mouth and quietly hiss until the threat is gone.<ref>{{Cite web|title=Opossum Sounds & Noises: What Do Opossums Sound Like?|url=https://www.crittercontrol.com/wildlife/opossums/opossum-noises|access-date=2022-01-24|website=www.crittercontrol.com}}</ref>

== Diet ==
Opossums eat insects, [[rodent]]s, birds, eggs, frogs, plants, fruits and grain. Some species may eat the skeletal remains of rodents and [[roadkill]] animals to fulfill their calcium requirements.<ref>{{Cite web|title=What Do Possums Eat? Facts About Their Diet {{!}} Terminix|url=https://www.terminix.com/pest-control/opossums/diet/|website=Terminix.com|language=en|access-date=2020-05-29}}</ref> In captivity, opossums will eat practically anything including dog and cat food, livestock fodder and discarded human food scraps and waste.

Many large opossums (Didelphini) are immune to the venom of rattlesnakes and pit vipers ([[Crotalinae]]) and regularly prey upon these snakes.<ref>{{cite journal |last1=Voss |first1=Robert S. |last2=Jansa |first2=Sharon A. |title=Snake-venom resistance as a mammalian trophic adaptation: lessons from didelphid marsupials |journal=Biological Reviews |date=November 2012 |volume=87 |issue=4 |pages=822–837 |doi=10.1111/j.1469-185X.2012.00222.x|pmid=22404916 |s2cid=21264310 }}</ref> This adaptation seems to be unique to the Didelphini, as their closest relative, the [[brown four-eyed opossum]], is not immune to snake venom.<ref>{{cite journal |last1=Perales |first1=Jonas |last2=Moussatché |first2=Haity |last3=Marangoni |first3=Sergio |last4=Oliveira |first4=Benedito |last5=Domont |first5=Gilberto B. |title=Isolation and partial characterization of an anti-bothropic complex from the serum of South American Didelphidae |journal=Toxicon |date=October 1994 |volume=32 |issue=10 |pages=1237–1249 |doi=10.1016/0041-0101(94)90353-0|pmid=7846694 |bibcode=1994Txcn...32.1237P }}</ref> Similar adaptations are seen in other small predatory mammals such as [[mongooses]] and [[hedgehogs]]. Didelphin opossums and crotaline vipers have been suggested to be in an [[evolutionary arms race]]. Some authors have suggested that this adaptation originally arose as a defense mechanism, allowing a rare reversal of an evolutionary arms race where the former prey has become the predator,<ref name = Voss2013/> whereas others have suggested it arose as a predatory adaptation given that it also occurs in other predatory mammals and does not occur in opossums that do not regularly eat other vertebrates.<ref name = Engelman2017/> The [[Bothrops|fer-de-lance]], one of the most venomous snakes in the [[New World]], may have developed its highly potent venom as a means to prey on or a defense mechanism against large opossums.<ref name = Voss2013>{{cite journal |last1=Voss |first1=Robert S. |title=Opossums (Mammalia: Didelphidae) in the diets of Neotropical pitvipers (Serpentes: Crotalinae): Evidence for alternative coevolutionary outcomes? |journal=Toxicon |date=May 2013 |volume=66 |pages=1–6 |doi=10.1016/j.toxicon.2013.01.013|pmid=23402839 |bibcode=2013Txcn...66....1V }}</ref>

== Habitat ==
[[File:Virginia Opossum range.png|thumb|''[[Didelphis virginiana|D. virginiana]]'' range, including introductions in the west. These areas expanded northwards (e.g., into Wisconsin and Minnesota).<ref name="Gardner2003">{{cite book|editor1=Feldhamer, G.A.|editor2= Thompson, B.C.|editor3= Chapman, J.A.|author1= Gardner, A.L.|chapter= Opossum: ''Didelphis virginiana'' |author2= Sunquist, M.E.|title=Wild Mammals of North America: Biology, Management, and Conservation|chapter-url= https://books.google.com/books?id=-xQalfqP7BcC&pg=PA4|year= 2003|publisher=JHU Press|isbn= 978-0-8018-7416-1|pages= 3–29}}</ref>]]
Opossums are found in North, Central, and [[South America]]. The Virginia opossum lives in regions as far north as [[Canada]] and as far south as Central America, while other types of opossums only inhabit countries south of the United States.<ref>{{Cite encyclopedia|url=https://www.britannica.com/animal/opossum|title=opossum {{!}} marsupial|encyclopedia=Encyclopedia Britannica|access-date=2017-04-03}}</ref> The Virginia opossum can often be found in wooded areas, though its habitat may vary widely.<ref>{{Cite web|url=http://www.nhptv.org/natureworks/opossum.htm|title=Virginia Opossum – Didelphis virginiana – NatureWorks|website=www.nhptv.org|access-date=2017-04-03}}</ref> Opossums are generally found in areas like forests, shrubland, mangrove swamps, rainforests and eucalyptus forests.<ref>{{Cite web|title=Animals in the Temperate Rainforest Biome|url=https://sciencing.com/animals-temperate-rainforest-biome-6801694.html|access-date=2021-05-18|website=Sciencing|date=22 November 2019 |language=en}}</ref> Opossums have been found moving northward.<ref name="Gardner2003"/><ref>{{Cite news|url=https://bangordailynews.com/2012/10/26/outdoors/maines-marsupials-opossums-continue-to-move-north/|title=Maine's marsupials: Opossums continue to move north|work=Bangor Daily News|date=2012-10-26}}</ref>

== Hunting and foodways ==
Until the early 20th century, the [[Virginia opossum]] was widely hunted and consumed in the [[United States]].<ref>Sutton, Keith (January 12, 2009)  [https://www.espn.com/outdoors/general/columns/story?columnist=sutton_keith&id=3827266 Possum days gone]. ESPN Outdoors.</ref><ref>[http://www.wildgamerecipes.org/ Wild Game Recipes online]. Retrieved 2009-12-29.</ref><ref>Powell, Bonnie Azab (2006-10-14) [http://www.ethicurean.com/2006/10/14/joy-of-cooking/ The joy of the ‘Joy of Cooking,’ circa 1962] {{Webarchive|url=https://web.archive.org/web/20061030204530/http://www.ethicurean.com/2006/10/14/joy-of-cooking/ |date=2006-10-30 }}. ethicurean.com.</ref><ref name="Apicius2012">{{cite book|author=Apicius|title=Cookery and Dining in Imperial Rome|url=https://books.google.com/books?id=22bOitPwJhwC&pg=PA205|date=2012|publisher=Courier Corporation|isbn=978-0-486-15649-1|pages=205–}}</ref> Opossum farms have been operated in the United States in the past.<ref>{{cite web|url=https://news.google.com/newspapers?nid=950&dat=19780906&id=QkZQAAAAIBAJ&pg=6448,1038928&hl=en|author=McNulty, Timothy|title=Possums Are His Passion|work=The Evening Independent |date= September 6, 1978}}</ref><ref>{{cite web|url=https://news.google.com/newspapers?nid=1916&dat=19780929&id=OeogAAAAIBAJ&pg=1067,6110703&hl=en|title='Possum Man' is Mayor|work=The Hour |date= September 29, 1978}}</ref><ref>{{cite web|url=http://static.cnhionline.com/crossvillechronicle/flashpromo/OldStuff/Opinion/moserkingpossums.html|title=King of the possums is dead|work=Crossville Chronicle|author=Moser, Mike|date=August 6, 2004}}</ref> Sweet potatoes were eaten together with the opossum in the American South.<ref name="Jones2007">{{cite book|author=Jones, Evan |title=American Food: The Gastronomic Story|url=https://books.google.com/books?id=5gs9PgAACAAJ|year=2007|publisher=Overlook Press|isbn=978-1-58567-904-1}}</ref><ref>{{cite web|url=http://www.geocities.com/Heartland/Estates/3443/possum_recipes.html|archive-url=https://web.archive.org/web/19991111043927/http://www.geocities.com/Heartland/Estates/3443/possum_recipes.html|url-status=dead|archive-date=11 November 1999|title=Possum Recipes|date=11 November 1999}}</ref> In 1909, a [[Frank Park#Political activity and election|"Possum and 'Taters" banquet]] was held in [[Atlanta]] to honor President-elect [[William Howard Taft]].<ref name="Clash">{{cite news|url=https://www.newspapers.com/clip/8584798/possum-dinner-in-coweta/|title=Over 'Possums Comes A Clash|publisher=[[Atlanta Constitution]]|date=February 4, 1909|access-date=July 19, 2020}}</ref><ref name="Worth">{{cite book|title=History of Worth County, Georgia: For the First Eighty Years, 18-54-1934|url=https://books.google.com/books?id=aEATAAAAYAAJ|year=1934|publisher=J.W. Burke Company|pages=83–84}}</ref>   South Carolina cuisine includes opossum,<ref>{{cite web|url=http://www.frc.ri.cmu.edu/~mcm/possum.html|archive-url=https://web.archive.org/web/19991109224048/http://www.frc.ri.cmu.edu/~mcm/possum.html|url-status=dead|archive-date=9 November 1999|title=Cooking a Possum|date=9 November 1999}}</ref> and President [[Jimmy Carter]] hunted opossums<ref name="Carter1995">{{cite book|author=Carter, Jimmy |title=Always a Reckoning, and Other Poems|url=https://books.google.com/books?id=B-WomB9aOgAC&pg=PA39|year=1995|publisher=Times Books|isbn=978-0-8129-2434-3|pages=39–}}</ref><ref name="Raum2011">{{cite book|author=Raum, Elizabeth |title=Gift of Peace: The Jimmy Carter Story: The Jimmy Carter Story|url=https://books.google.com/books?id=7doAYxChjq0C&pg=PT15|date=13 September 2011|publisher=Zonderkidz|isbn=978-0-310-72757-6|pages=15–}}</ref> in addition to other small game.<ref>{{cite web|url=http://www.gon.com/news/president-jimmy-carter-inducted-into-georgia-hunting-and-fishing-hall-of-fame|title=President Jimmy Carter Inducted into Georgia Hunting and Fishing Hall of Fame|date=7 April 2016 }}</ref><ref>{{cite web|url=https://www.orlandosentinel.com/2001/02/11/carter-shares-times/|title=Carter Shares Times|date=February 11, 2001|author=Doolittle, Leslie |work=Orlando Sentinel }}</ref>

In [[Dominica]], [[Grenada]], [[Trinidad]], [[Saint Lucia]] and [[Saint Vincent and the Grenadines]], the [[common opossum]] or ''manicou'' is popular and can only be hunted during certain times of the year owing to overhunting.<ref>{{Cite web|url=https://www.worldwildlife.org/ecoregions/nt0179|title=Southern Caribbean: Islands of Martinique, Dominica, Grenada, Saint Lucia, Saint Vincent and the Grenadines {{!}} Ecoregions {{!}} WWF|website=World Wildlife Fund|access-date=2017-05-14}}</ref> The meat is traditionally prepared by smoking, then stewing. It is light and fine-grained, but the musk glands must be removed as part of preparation. The meat can be used in place of rabbit and chicken in recipes. Historically, hunters in the Caribbean would place a barrel with fresh or rotten fruit to attract opossums that would feed on the fruit or insects.

In northern/central Mexico, opossums are known as ''tlacuache'' or ''tlacuatzin''. Their tails are eaten as a [[Alternative medicine|folk remedy]] to improve fertility.<ref>{{cite book|chapter-url=http://www.medicinatradicionalmexicana.unam.mx/|language=es|title=Biblioteca Digital de la Medicina Tradicional Mexicana|chapter=tlacuache|publisher=Biblioteca Digital de la Medicina Tradicional Mexicana}}</ref> In the Yucatán peninsula they are known in the [[Yucatec Maya language|Yucatec Mayan language]] as "och"<ref>{{Cite book|url=https://books.google.com/books?id=HJCza7sWUaMC&pg=PA149|title=Telling and Being Told: Storytelling and Cultural Control in Contemporary Yucatec Maya Literatures|first=Paul M.|last=Worley|date=2013|publisher=University of Arizona Press|via=Google Books|isbn=9780816530267}}</ref> and they are not considered part of the regular diet by Mayan people, but still considered edible in times of famine.

Opossum oil (possum grease) is high in [[essential fatty acid]]s and has been used as a chest rub and a carrier for [[arthritis]] remedies given as salves.<ref>{{cite journal|doi= 10.1590/S1981-81222008000300005|title= Animais medicinais: Conhecimento e uso entre as populações ribeirinhas do rio Negro, Amazonas, Brasil|journal= Boletim do Museu Paraense Emílio Goeldi. Ciências Humanas|volume= 3|issue= 3|pages= 343–357|year= 2008|last1= Silva|first1= Andréa Leme da|doi-access= free|hdl= 11449/27066|hdl-access= free}}</ref><ref>{{cite journal|doi=10.1590/1809-4392200332290|title=Produtos e subprodutos da medicina popular comercializados na cidade de Boa Vista, Roraima|journal=Acta Amazonica|volume=33|issue=2|pages=281–290|year=2003|last1=Pinto|first1=Angélica Auxiliadora da Costa|last2=Maduro|first2=Cice Batalha|doi-access=free|bibcode=2003AcAma..33..281P }}</ref><ref>{{cite journal|doi=10.1186/1746-4269-8-37|pmid=23013927|pmc=3502351|title=Medicinal use of fauna by a traditional community in the Brazilian Amazonia|journal=Journal of Ethnobiology and Ethnomedicine|volume=8|pages=37|year=2012|last1=Barros|first1=Flávio B.|last2=Varela|first2=Susana AM|last3=Pereira|first3=Henrique M.|last4=Vicente|first4=Luís |doi-access=free }}</ref>

Opossum pelts have long been part of the [[fur trade]].

== Classification ==
{{main|List of didelphimorphs}}
{{cladogram
|title=Phylogeny of a 5,911 species 31 gene supertree<ref name="Upham 2019">{{Cite journal |last1=Upham |first1=Nathan S. |last2=Esselstyn |first2=Jacob A. |last3=Jetz |first3=Walter |date=2019 |title=Inferring the mammal tree: Species-level sets of phylogenies for questions in ecology, evolution and conservation |journal=PLOS Biol |volume=17 |issue=12 |pages=e3000494 |doi=10.1371/journal.pbio.3000494 |pmid=31800571 |pmc=6892540 |doi-access=free }}</ref><ref>{{cite journal |last1=Upham |first1=Nathan S. |last2=Esselstyn |first2=Jacob A. |last3=Jetz |first3=Walter |year=2019 |title=DR_on4phylosCompared_linear_richCol_justScale_ownColors_withTips_80in |url=https://github.com/n8upham/MamPhy_v1/blob/master/Fig6_compare_tipDRs/DR_on4phylosCompared_linear_richCol_justScale_ownColors_withTips_80in.pdf |journal=PLOS Biology |volume=17 |issue=12 |pages= e3000494|doi=10.1371/journal.pbio.3000494 |doi-access=free |pmid=31800571 |pmc=6892540 }}</ref>|
{{clade|style=font-size:90%;line-height:100%;width:350px;
|1={{clade
  |1={{clade
  |label1=[[Caluromyinae]]
  |1={{clade
    |1=''[[Caluromysiops]]''
    |2=''[[Caluromys]]''
     }}
     }}
  |2={{clade
    |1={{clade
    |label1=[[Glironiinae]]
    |1={{clade
      |1=''[[Chacodelphys]]''
      |2=''[[Glironia]]''
       }}
       }}
    |2={{clade
      |label1=[[Hyladelphinae]]
      |1=''[[Hyladelphys]]''
      |label2=[[Didelphinae]]
      |2={{clade
        |1={{clade
        |label1=Marmosini
        |1={{clade
          |1={{clade
            |1=''[[Tlacuatzin]]''
            |2=''[[Marmosa]]''
             }}
          |2=''[[Monodelphis]]''
           }}
           }}
        |2={{clade
          |1={{clade
            |label1=Metachirini
            |1=''[[Metachirus]]''
            |label2=Didelphini
            |2={{clade
              |1=''[[Chironectes]]''
              |2={{clade
                |1=''[[Lutreolina]]''
                |2={{clade
                  |1=''[[Philander (mammal)|Philander]]''
                  |2=''[[Didelphis]]''
                   }}
                 }}
               }}
             }}
          |2={{clade
          |label1=Thylamyini
          |1={{clade
            |1=''[[Marmosops]]''
            |2={{clade
              |1=''[[Cryptonanus]]''
              |2={{Clade
                |1=''[[Gracilinanus]]''
                |2={{clade
                  |1=''[[Lestodelphys]]''
                  |2=''[[Thylamys]]''
                   }}
                 }}
               }}
             }}
             }}
           }}
         }}
       }}
     }}
   }}
 }}
|}}

Classification based on Voss (2022), species based on the [[American Society of Mammalogists]] (2023)<ref>{{Cite journal |last=Voss |first=Robert S. |date=2022-04-04 |title=An Annotated Checklist of Recent Opossums (Mammalia: Didelphidae) |url=https://bioone.org/journals/bulletin-of-the-american-museum-of-natural-history/volume-455/issue-1/0003-0090.455.1.1/An-Annotated-Checklist-of-Recent-Opossums-Mammalia-Didelphidae/10.1206/0003-0090.455.1.1.full |journal=Bulletin of the American Museum of Natural History |volume=455 |issue=1 |pages=1–76 |doi=10.1206/0003-0090.455.1.1 |issn=0003-0090}}</ref><ref>{{Cite web |last=Mammal Diversity |date=2023-04-15 |title=Mammal Diversity Database |url=https://zenodo.org/records/7830771 |access-date=2023-12-11 |doi=10.5281/zenodo.7830771}}</ref><ref>{{Cite web|last=McClure|first=Sonny R.|title=New opossum species named after UWO biologist Greg Adler|url=https://www.abigailgroff.com/new-opossum-species-named-after-uwo-biologist-greg-adler/|access-date=2021-12-13|website=www.abigailgroff.com|date=8 December 2021 |language=en-US}}</ref>

* '''Family Didelphidae'''
** Subfamily [[Glironia|Glironiinae]]
*** Genus ''[[Glironia]]''
**** [[Bushy-tailed opossum]] (''Glironia venusta'')
** Subfamily [[Caluromyinae]]
*** Genus ''[[Caluromys]]'' [[File:Cuíca-lanosa.jpg|thumb|[[Bare-tailed woolly opossum]], ''Caluromys philander'']][[File:Central American woolly opossum (Caluromys derbianus) male.jpg|thumb|[[Derby's woolly opossum]], ''Caluromys derbianus'']]
**** Subgenus ''Caluromys''
***** [[Bare-tailed woolly opossum]] (''Caluromys philander'')
**** Subgenus ''Mallodelphys''
***** [[Derby's woolly opossum]] (''Caluromys derbianus'')
***** [[Brown-eared woolly opossum]] (''Caluromys lanatus'')
*** Genus ''[[Caluromysiops]]''
**** [[Black-shouldered opossum]] (''Caluromysiops irrupta'')
** Subfamily [[Hyladelphinae]]
*** Genus ''[[Hyladelphys]]''
**** [[Kalinowski's mouse opossum]] (''Hyladelphys kalinowskii'')
*** Genus †''[[Sairadelphys]]'' <small>Oliveira et al. 2011</small>
**** †''Sairadelphys tocantinensis'' <small>Oliveira et al. 2011</small>
** Subfamily [[Didelphinae]]
*** Tribe [[Metachirini]] [[File:Vieraugen-Opossum (Metachirus nudicaudatus).jpg|thumb|[[Brown four-eyed opossum]], ''Metachirus nudicaudatus'']]
**** Genus ''[[Metachirus]]''
***** [[Aritana's brown four-eyed opossum]] (''Metachirus aritanai'')
*****[[Common brown four-eyed opossum]] (''Metachirus myosuros'')
*****[[Brown four-eyed opossum|Guianan brown four-eyed opossum]] (''Metachirus nudicaudatus'')
*** Tribe Didelphini [[File:Schwimmbeutler-drawing2.jpg|thumb|[[Water opossum]], ''Chironectes minimus'']]
**** Genus ''[[Chironectes]]''
***** [[Water opossum]] or [[Water opossum|yapok]] (''Chironectes minimus'')
**** Genus ''[[Lutreolina]]''
***** †''[[Lutreolina biforata]]'' <small>(Ameghino 1904) Goin & Pardiñas 1996</small><ref name="hyperdidelphys">{{cite journal| title=Revision de las especies del genero ''Hyperdidelphys'' Ameghino, 1904 (Mammalia, Marsupialia, Didelphidae. Su significacion filogenetica, estratigrafica y adaptativa en el Neogeno del Cono Sur sudamericano|first=Francisco J.|last=Goin|author2=Pardinas, Ulyses F. J. |journal=[[Estudios Geológicos]]|year=1996|volume=52|issue=5–6|pages=327–359|doi=10.3989/egeol.96525-6275|doi-access=free}}</ref>
***** [[Big lutrine opossum]] or little water opossum (''Lutreolina crassicaudata'')[[File:Cambridge Natural History Mammalia Fig 084.jpg|thumb|[[Big lutrine opossum]], ''Lutreolina crassicaudata'']]
***** †''[[Lutreolina materdei]]'' <small>Goin & De los Reyes 2011</small><ref>{{cite journal| title=Contribution to the knowledge of living representatives of the genus ''Lutreolina'' Thomas, 1910 (Mammalia, Marsupialia, Didelphidae)|jstor=20627135|first=Francisco J.|last=Goin|author2=de los Reyes, Martin |journal=[[Historia Natural]]|year=2011|volume=1|issue=2|pages=15–25}}</ref>
***** [[Massoia's lutrine opossum]] (''Lutreolina massoia'')<ref>{{cite journal|doi=10.1644/13-MAMM-A-246|title= A new species of lutrine opossum, genus ''Lutreolina'' Thomas (Didelphidae), from the South American Yungas|journal= Journal of Mammalogy|volume= 95|issue= 2|pages= 225|year= 2014|last1= Martínez-Lanfranco|first1= Juan A.|last2= Flores|first2= David|last3= Jayat|first3= J. Pablo|last4= d'Elía|first4= Guillermo|s2cid= 85599660|doi-access= free|hdl= 11336/29722|hdl-access= free}}</ref>
***** †''[[Lutreolina tracheia]]'' <small>Rovereto 1914</small>
**** †Genus ''[[Hyperdidelphys]]'' <small>Ameghino 1904</small>
***** †''[[Hyperdidelphys dimartinoi]]'' <small>Goin & Pardiñas 1996</small><ref name="hyperdidelphys" />
***** †''[[Hyperdidelphys inexpectata]]'' <small>(Ameghino 1889) Marshall 1982</small><ref name="hyperdidelphys" />
***** †''[[Hyperdidelphys parvula]]'' <small>Ameghino 1904</small><ref name="hyperdidelphys" />
***** †''[[Hyperdidelphys pattersoni]]'' <small>(Reig 1952) Marshall 1982</small><ref name="hyperdidelphys" />
**** Genus ''[[Didelphis]]'' [[File:Didelphis albiventris, Bahia, Brazil.jpg|thumb|[[White-eared opossum]], ''Didelphis albiventris'']][[File:Didelphis aurita photo-Christian Roger Dockhorn.JPG|thumb|[[Big-eared opossum]], ''Didelphis aurita'']][[File:Rabipelao2.jpg|thumb|[[Common opossum]], ''Didelphis marsupialis'']][[File:Didelphis pernigra 29825860 1.jpg|thumb|[[Andean white-eared opossum]], ''Didelphis pernigra'']]
***** [[White-eared opossum]] (''Didelphis albiventris'')
***** [[Big-eared opossum]] (''Didelphis aurita'')
***** [[Guianan white-eared opossum]] (''Didelphis imperfecta'')
***** [[Common opossum]] (''Didelphis marsupialis'')
***** [[Andean white-eared opossum]] (''Didelphis pernigra'')
***** †''Didelphis solimoensis''<ref>{{cite journal|title=The oldest species of ''Didelphis'' (Mammalia, Marsupialia, Didelphidae) from the late Miocene of Amazonia|first=Mario A.|last=Cozzuol|author2=Goin, Francisco J. |author3=de los Reyes, Martin |author4=Ranzi, Alceu |journal=[[Journal of Mammalogy]]|year=2006|volume=87|issue=4|pages=663–667|doi=10.1644/05-MAMM-A-282R2.1|s2cid=85646145|doi-access=free}}</ref>
***** [[Virginia opossum]] (''Didelphis virginiana'')
**** Genus ''[[Gray and black four-eyed opossum|Philander]]'' [[File:Cuica verdadeira2.jpg|thumb|[[Gray four-eyed opossum]], ''Philander opossum'']]
***** [[Anderson's four-eyed opossum]] (''Philander andersoni'')
***** [[Common four-eyed opossum]] (''Philander canus'')
***** [[Deltaic four-eyed opossum]] (''Philander deltae'')
***** [[Southeastern four-eyed opossum]] (''Philander frenatus'')<!--no longer recognized. Synonym of Philander nigratus-->
***** [[McIlhenny's four-eyed opossum]] (''Philander mcilhennyi'')
***** [[Dark four-eyed opossum]] (''Philander melanurus'')
***** [[Mondolfi's four-eyed opossum]] (''Philander mondolfii'') <!-- No longer recognized. Synonym of Philander canus  -->
***** [[Black four-eyed opossum]] (''Philander nigratus'')
***** [[Olrog's four-eyed opossum]] (''Philander olrogi'')<!--No longer recognized. Synonym of Philander canus -->
***** [[Gray four-eyed opossum]] (''Philander opossum'')
***** [[Pebas four-eyed opossum]] (''Philander pebas'')
***** [[Southern four-eyed opossum]] (''Philander quica'')
***** [[Northern four-eyed opossum]] (''Philander vossi'')
**** †Genus ''[[Thylophorops]]'' <small>Reig 1952</small>
***** †''[[Thylophorops chapadmalensis]]'' <small>Reig 1952</small><ref name="hyperdidelphys" />
***** †''[[Thylophorops lorenzinii]]'' <small>Goin et al. 2009</small><ref name="Goin 2009 35–46" />
***** †''[[Thylophorops perplana]]'' <small>(Ameghino 1904) Goin & Pardiñas 1996</small><ref name="hyperdidelphys" />
*** Tribe Marmosini
**** Genus †''[[Hesperocynus]]'' <small>Forasiepi et al. 2009</small>
***** †''[[Hesperocynus dolgopolae]]'' <small>(Reig 1952) Forasiepi et al. 2009</small>
**** Genus ''[[Marmosa]]''
***** †''Marmosa contrerasi'' <small>Mones 1980</small>
***** Subgenus ''Eomarmosa''
****** [[Red mouse opossum]] (''Marmosa rubra'')
***** Subgenus ''Exulomarmosa''
****** [[Isthmian mouse opossum]] (''Marmosa isthmica'')
****** [[Mexican mouse opossum]] (''Marmosa mexicana'')
****** [[Robinson's mouse opossum]] (''Marmosa robinsoni'')
****** [[Simon's mouse opossum]] (''Marmosa simonsi'')
****** [[Guajira mouse opossum]] (''Marmosa xerophila'')
****** [[Zeledon's mouse opossum]] (''Marmosa zeledoni'')
***** Subgenus ''Marmosa'' [[File:Marmosa robinsoni.jpg|thumb|[[Robinson's mouse opossum]], ''Marmosa robinsoni'']]
****** [[Quechuan mouse opossum]] (''Marmosa macrotarsus'')
****** [[Linnaeus's mouse opossum]] (''Marmosa murina'')
****** [[Tyler's mouse opossum]] (''Marmosa tyleriana'')
****** [[Waterhouse's mouse opossum]] (''Marmosa waterhousei'')
***** Subgenus ''Micoureus'' [[File:Cuíca - Marmosa paraguayana cropped.jpg|thumb|[[Tate's woolly mouse opossum]], ''Marmosa paraguayanus'']]
****** [[Adler's mouse opossum]] (''Marmosa adleri)''
****** [[Alston's mouse opossum|Alston's woolly mouse opossum]] (''Marmosa alstoni'')
****** [[White-bellied woolly mouse opossum]] (''Marmosa constantiae'')
****** [[Woolly mouse opossum|Northeastern woolly mouse opossum]] (''Marmosa demerarae'')
****** [[Northwestern woolly mouse opossum]] (''Marmosa germana'')
****** [[Jansa's woolly mouse opossum]] (''Marmosa jansae'')
******†''[[Marmosa laventica]]'' <small>Marshall 1976</small><ref name="goin">{{cite book|last1=Goin|first1=Francisco J.|title=Vertebrate Paleontology of the Miocene in Colombia. A History of the Neotropical Fauna|publisher=Smithsonian Institution Scholarly Press|year=1997|isbn=978-1-56098-418-4|pages=185–204|chapter=New clues for understanding Neogene marsupial radiations}}</ref>
****** [[Brazilian woolly mouse opossum]] (''Marmosa limae'')<!-- No longer recognized. Synonym of Marmosa demerarae --> 
****** [[Merida woolly mouse opossum]] (''Marmosa meridae'')<!-- No longer recognized. Synonym of Marmosa demerarae -->
****** [[Nicaraguan woolly mouse opossum]] (''Marmosa nicaraguae'')
****** [[Tate's woolly mouse opossum]] (''Marmosa paraguayana'')
****** [[Peruvian woolly mouse opossum]] (''Marmosa parda'')
****** [[Anthony's woolly mouse opossum]] (''Marmosa perplexa'')
****** [[Little woolly mouse opossum]] (''Marmosa phaea'')
****** [[Bolivian woolly mouse opossum]] (''Marmosa rapposa'')
****** [[Bare-tailed woolly mouse opossum]] (''Marmosa rutteri'')
***** Subgenus ''Stegomarmosa''
****** [[Heavy-browed mouse opossum]] (''Marmosa andersoni'')
****** [[Rufous mouse opossum]] (''Marmosa lepida'')
**** Genus ''[[Monodelphis]]'' [[File:Monodelphis dimidiata.jpg|thumb|[[Yellow-sided opossum]], ''Monodelphis dimidiata'']][[File:Monodelphis domestica93-300b.jpg|thumb|[[Gray short-tailed opossum]], ''Monodelphis domestica'']]
***** Subgenus ''Microdelphys''
****** [[Northern three-striped opossum]] (''Monodelphis americana'')
****** [[Gardner's short-tailed opossum]] (''Monodelphis gardneri'')
****** [[Ihering's three-striped opossum]] (''Monodelphis iheringi'')
****** [[Chestnut-striped opossum]] (''Monodelphis rubida'')<!-- No longer recognized. Synonym of Monodelphis americana -->
****** [[Long-nosed short-tailed opossum]] (''Monodelphis scalops'')
****** [[Southern three-striped opossum]] (''Monodelphis theresa'')<!-- No longer recognized. Synonym of Monodelphis scalops -->
****** [[Red three-striped opossum]] (''Monodelphis umbristriata'')<!-- No longer recognized. Synonym of Monodelphis americana -->
***** Subgenus ''Monodelphiops''
****** [[Yellow-sided opossum]] (''Monodelphis dimidiata'')
****** [[Southern red-sided opossum]] (''Monodelphis sorex'')<!-- No longer recognized. Synonym of Monodelphis dimidiata -->
****** [[One-striped opossum]] (''Monodelphis unistriata'')
***** Subgenus ''Monodelphis''
****** [[Arlindo's short-tailed opossum]] (''Monodelphis arlindoi'')<ref name="wiley1">{{cite journal |last1=Pavan |first1=Silvia Eliza |last2=Rossi |first2=Rogerio Vieira |last3=Schneider |first3=Horacio |year=2012 |title=Species diversity in the ''Monodelphis brevicaudata'' complex (Didelphimorphia: Didelphidae) inferred from molecular and morphological data, with the description of a new species |journal=Zoological Journal of the Linnean Society |volume=165 |pages=190–223 |doi=10.1111/j.1096-3642.2011.00791.x |doi-access=free}}</ref>
****** [[Northern red-sided opossum]] (''Monodelphis brevicaudata'')
****** [[Gray short-tailed opossum]] (''Monodelphis domestica'')
****** [[Amazonian red-sided opossum]] (''Monodelphis glirina'')
****** [[Marajó short-tailed opossum]] (''Monodelphis maraxina'')<!-- No longer recognized. Synonym of Monodelphis glirina -->
****** [[Hooded red-sided opossum]] (''Monodelphis palliolata'')
****** [[Santa Rosa short-tailed opossum]] (''Monodelphis sanctaerosae'')<ref name="Voss-2012">{{cite journal |last1=Voss |first1=Robert S. |last2=Pine |first2=Ronald H. |last3=Solari |first3=Sergio |year=2012 |title=A New Species of the Didelphid Marsupial Genus ''Monodelphis'' from Eastern Bolivia |url=https://zenodo.org/record/5360285 |journal=American Museum Novitates |issue=3740 |pages=1–14 |doi=10.1206/3740.2 |s2cid=83545414}}</ref>
****** [[Touan short-tailed opossum]] (''Monodelphis touan'')<ref name="wiley1" />
****** [[Voss's short-tailed opossum]] (''Monodelphis vossi'')
***** Subgenus ''Mygalodelphys''
****** [[Sepia short-tailed opossum]] (''Monodelphis adusta'')<ref name="wiley1" />
****** [[Handley's short-tailed opossum]] (''Monodelphis handleyi'')<ref>Solari, S. (2016). ''Monodelphis handleyi''. The IUCN Red List of Threatened Species {{doi|10.2305/IUCN.UK.2016-3.RLTS.T199833A22171921.en}}</ref>
****** [[Pygmy short-tailed opossum]] (''Monodelphis kunsi'')
****** [[Osgood's short-tailed opossum]] (''Monodelphis osgoodi'')
****** [[Peruvian short-tailed opossum]] (''Monodelphis peruviana'')
****** [[Monodelphis pinocchio|Long-nosed short-tailed opossum]] (''Monodelphis pinocchio'')
****** [[Reig's opossum]] ''(Monodelphis reigi)''
****** [[Ronald's opossum]] (''Monodelphis ronaldi'')
****** [[Saci short-tailed opossum]] (''Monodelphis saci'')<ref name="Voss-2012" />
***** Subgenus ''Pyrodelphys''
****** [[Emilia's short-tailed opossum]] (''Monodelphis emiliae'')
**** Genus †''[[Sparassocynus]]'' <small>Mercerat 1898</small><ref name =BeckTaglioretti>{{cite journal |last1=Beck |first1=Robin M. D. |last2=Taglioretti |first2=Matias L. |title=A Nearly Complete Juvenile Skull of the Marsupial ''Sparassocynus derivatus'' from the Pliocene of Argentina, the Affinities of "Sparassocynids", and the Diversification of Opossums (Marsupialia; Didelphimorphia; Didelphidae) |journal=Journal of Mammalian Evolution |date=2019 |volume=27 |issue=3 |pages=385–417 |doi=10.1007/s10914-019-09471-y|s2cid=198190603 |doi-access=free }}</ref>
***** †''[[Sparassocynus bahiai]]'' <small>Mercerat 1898</small>
***** †''[[Sparassocynus derivatus]]'' <small>Reig & Simpson 1972</small>
***** †''[[Sparassocynus maimarai]]'' <small>Abello et al. 2015</small>
***** †''[[Sparassocynus heterotopicus]]'' <small>Villarroel & Marshall 1983</small>
**** Genus †''[[Thylatheridium]]'' <small>Reig 1952</small>
***** †''[[Thylatheridium cristatum]]'' <small>Reig 1952</small>
***** †''[[Thylatheridium hudsoni]]'' <small>Goin & Montalvo 1988</small>
***** †''[[Thylatheridium pascuali]]'' <small>Reig 1958</small>
**** Genus ''[[Tlacuatzin]]''<ref name="VossJansa2009">{{cite journal |last=Voss |first=Robert S. |author2=Jansa, Sharon A. |year=2009 |title=Phylogenetic relationships and classification of didelphid marsupials, an extant radiation of New World metatherian mammals |journal=[[Bulletin of the American Museum of Natural History]] |volume=322 |pages=1–177 |doi=10.1206/322.1 |s2cid=85017821 |hdl-access=free |hdl=2246/5975}}</ref>
***** [[Balsas gray mouse opossum]] (''Tlacuatzin balsasensis'')
***** [[Grayish mouse opossum|Tehuantepec gray mouse opossum]] (''Tlacuatzin canescens'')
***** [[Yucatan gray mouse opossum]] (''Tlacuatzin gaumeri'')
***** [[Tres Marías gray mouse opossum]] (''Tlacuatzin insularis'')
***** [[Northern gray mouse opossum]] (''Tlacuatzin sinaloae'')
**** †Genus ''[[Zygolestes]]'' <small>Ameghino 1898</small>
***** †''[[Zygolestes paramensis]]'' <small>Ameghino 1898</small>
***** †''[[Zygolestes tatei]]'' <small>Goin, Montalvo & Visconti 2000</small>
*** Tribe Thylamyini
**** Genus ''[[Chacodelphys]]''
***** [[Chacoan pygmy opossum]] (''Chacodelphys formosa'')
**** Genus ''[[Cryptonanus]]''
***** [[Agricola's gracile opossum]] (''Cryptonanus agricolai'')
***** [[Chacoan gracile opossum]] (''Cryptonanus chacoensis'')
***** [[Guahiba gracile opossum]] (''Cryptonanus guahybae'')
***** †[[Red-bellied gracile opossum]] (''Cryptonanus ignitus'')<!--No longer recognized. Synonym of Cryptonanus chacoensis-->
***** [[Unduavi gracile opossum]] (''Cryptonanus unduaviensis'')
**** Genus ''[[Gracilinanus]]''
***** [[Aceramarca gracile opossum]] (''Gracilinanus aceramarcae'')
***** [[Agile gracile opossum]] (''Gracilinanus agilis'')
***** [[Wood sprite gracile opossum]] (''Gracilinanus dryas'')
***** [[Emilia's gracile opossum]] (''Gracilinanus emilae'')
***** [[Northern gracile opossum]] (''Gracilinanus marica'')
***** [[Brazilian gracile opossum]] (''Gracilinanus microtarsus'')
***** [[Peruvian opossum]] (''Gracilinanus peruanus'')
**** Genus ''[[Lestodelphys]]''
***** [[Patagonian opossum]] (''Lestodelphys halli'')
***** †''Lestodelphys juga'' <small>(Ameghino 1889)</small>
**** Genus ''[[Marmosops]]'' [[File:Marmosops incanus.jpg|thumb|[[Gray slender opossum]], ''Marmosops incanus'']]
***** Subgenus ''Marmosops''
****** [[Tschudi's slender opossum]] (''Marmosops caucae'')
****** [[Creighton's slender opossum]] (''Marmosops creightoni'')
****** [[Dorothy's slender opossum]] (''Marmosops dorothea'')<!-- No longer recognized. Synonym of Marmosops noctivagus -->
****** [[Andean slender mouse opossum]] (''Marmosops impavidus'')<!-- No longer recognized. Synonym of Marmosops caucae -->
****** [[Gray slender opossum]] (''Marmosops incanus'')
****** [[Neblina slender opossum]] (''Marmosops neblina'')<!-- No longer recognized. Synonym of Marmosops caucae -->
****** [[White-bellied slender opossum]] (''Marmosops noctivagus'')
****** [[Spectacled slender opossum]] (''Marmosops ocellatus'')
****** [[Brazilian slender opossum]] (''Marmosops paulensis'')
****** [[Soini's slender opossum]] (''Marmosops soinii'')
***** Subgenus ''Sciophanes''
****** [[Bishop's slender opossum]] (''Marmosops bishopi'')
****** [[Carr's slender opossum]] (''Marmosops carri'')
****** [[Cordillera slender opossum]] (''Marmosops chucha'')
****** [[Narrow-headed slender opossum]] (''Marmosops cracens'')<!-- No longer recognized. Synonym of Marmosops fuscatus -->
****** [[Dusky slender opossum]] (''Marmosops fuscatus'')
****** [[Handley's slender opossum]] (''Marmosops handleyi'')
****** [[Panama slender opossum]] (''Marmosops invictus'')
****** [[Junin slender opossum]] (''Marmosops juninensis'')
****** [[Río Magdalena slender opossum]] (''Marmosops magdalenae'')
****** [[Silva's slender opossum]] (''Marmosops marina'')
****** [[Ojasti's slender opossum]] (''Marmosops ojastii'')
****** [[Pantepui slender opossum]] (''Marmosops pakaraimae'')
****** [[Delicate slender opossum]] (''Marmosops parvidens'')
****** [[Pinheiro's slender opossum]] (''Marmosops pinheiroi'')
****** [[Woodall's slender opossum]] (''Marmosops woodalli'')
**** Genus ''[[Thylamys]]'' <!--[https://translate.google.com/translate?hl=en&sl=sp&u=[[:es:Thylamys]] translation of Spanish article]--> [[File:Llaca.jpg|thumb|[[Elegant fat-tailed mouse opossum]], ''Thylamys elegans'']]
***** Subgenus ''Thylamys''
****** [[Cinderella fat-tailed mouse opossum]] (''Thylamys cinderella'')<!-- No longer recognized. Synonym of Thylamys venustus  -->
****** [[Mesopotamian fat-tailed mouse opossum]] (''Thylamys citellus'')<ref>Flores, D. & Teta, P. (2016). ''Thylamys citellus''. The IUCN Red List of Threatened Species {{doi|10.2305/IUCN.UK.2016-2.RLTS.T199835A22172943.en}}</ref><!-- No longer recognized. Synonym of Thylamys pusillus  -->
****** [[Elegant fat-tailed mouse opossum]] (''Thylamys elegans'')
****** [[Paraguayan fat-tailed mouse opossum]] (''Thylamys macrurus'')
****** [[White-bellied fat-tailed mouse opossum]] (''Thylamys pallidior'')
****** [[Dry Chaco fat-tailed mouse opossum]] (''Thylamys pulchellus'')<ref>Flores, D. & Teta, P. (2016). ''Thylamys pulchellus''. The IUCN Red List of Threatened Species {{doi|10.2305/IUCN.UK.2016-2.RLTS.T199834A22172571.en}}</ref><!-- No longer recognized. Synonym of Thylamys pusillus  -->
****** [[Common fat-tailed mouse opossum|Chacoan fat-tailed mouse opossum]] (''Thylamys pusillus'')
****** [[Argentine fat-tailed mouse opossum]] (''Thylamys sponsorius'')
****** [[Tate's fat-tailed mouse opossum]] (''Thylamys tatei'')
****** [[Buff-bellied fat-tailed mouse opossum]] (''Thylamys venustus'')
***** Subgenus ''Xerodelpys''
****** [[Karimi's fat-tailed mouse opossum]] (''Thylamys karimii'')
****** [[Dwarf fat-tailed mouse opossum]] (''Thylamys velutinus'')
***** †''[[Thylamys colombianus]]'' <small>Goin 1997</small><ref name="goin" />
***** †''[[Thylamys minutus]]'' <small>Goin 1997</small><ref name="goin" />
***** †''[[Thylamys pinei]]'' <small>Goin, Montalvo & Visconti 2000</small><ref>{{cite journal|title=Los marsupiales (Mammalia) del Mioceno Superior de la Formacion Cerro Azul (Provincia de La Pampa, Argentina) |first1=Francisco J. |last1=Goin |author2=Montalvo, C.I. |author3=Visconti, G. |journal=[[Estudios Geológicos]]|year=2000|volume=56|issue=1–2 |pages=101–126|doi=10.3989/egeol.00561-2158|doi-access=free |hdl=11336/108700 |hdl-access=free }}</ref>
***** †''[[Thylamys zettii]]'' <small>Goin 1997</small><ref>{{cite journal|title=''Thylamys zettii'', nueva especie de marmosino (Marsupialia, Didelphidae) del Cenozoico tardio de la region Pampeana|first=Francisco J.|last=Goin|journal=[[Ameghiniana]]|year=1997|volume=34|issue=4|pages=481–484}}</ref>

==See also==
* [[List of mammal genera]]
* [[List of prehistoric mammals]]

== References ==
{{Reflist}}

== External links ==
{{Wiktionary}}
* [https://collections.tepapa.govt.nz/topic/2858 "Possums or Opossums?"]—on [[Museum of New Zealand Te Papa Tongarewa]]
* {{UCSC genomes|monDom5}}
{{Metatheria|M.|state=autocollapse}}
{{Mammals}}
{{Didelphimorphia}}
{{Taxonbar|from=Q21834}}

{{Authority control}}

[[Category:Opossums| ]]
[[Category:Extant Miocene first appearances]]
[[Category:Marsupials of Central America]]
[[Category:Marsupials of North America]]
[[Category:Marsupials of South America]]
[[Category:Marsupials]]
[[Category:Miocene mammals of South America]]
[[Category:Taxa named by John Edward Gray]]