Brown four-eyed opossum

{{Short description|Species of marsupial}}

{{Speciesbox

| name = Brown four-eyed opossum{{MSW3 Didelphimorphia | id = 10400110 | page = 12}}

| image = Vieraugen-Opossum (Metachirus nudicaudatus).jpg

| status = LC

| status_system = IUCN3.1

| status_ref = {{cite iucn |author=Brito, D. |author2=Astúa, D. |author3=Lew, D. |author4=de la Sancha, N. |date=2021 |title=Metachirus nudicaudatus |volume=2021 |page=e.T40509A197311536 |doi=10.2305/IUCN.UK.2021-1.RLTS.T40509A197311536.en |access-date=11 November 2021}}

| display_parents = 3

| grandparent_authority = Reig et al., 1987

| genus = Metachirus

| parent_authority = Burmeister, 1854

| species = nudicaudatus

| authority = (É. Geoffroy, 1803)

| range_map = Brown Four-eyed Opossum area.png

| range_map_caption = Brown four-eyed opossum range

}}

The brown four-eyed opossum (Metachirus nudicaudatus) is a pouchless marsupial{{Cite book | last = Eisenberg | first = John F. |author2=Redford, Kent H. | title = Mammals of the Neotropics, Volume 3: The Central Neotropics: Ecuador, Peru, Bolivia, Brazil | publisher = University of Chicago Press | date = May 15, 2000 | pages = 77–78 | url = https://books.google.com/books?id=p2MDAzCeQQoC&pg=PA77 | isbn =978-0-226-19542-1 |oclc =493329394}} of the family Didelphidae. It is found in different forested habitats of Central and South America, from Nicaragua to Brazil and northern Argentina, including southeastern Colombia, Paraguay and eastern Peru and Bolivia, at elevations from sea level to {{convert|1500|m|abbr=on}}. It is the only recognized species in the genus Metachirus, but molecular phylogenetics studies suggest that it should probably be split into several species. Population densities are usually low, and it is uncommon in parts of Central America. A density of {{convert|25.6|PD/km2|abbr=on}} was reported near Manaus, Brazil. Its karyotype has 2n = 14 and FN = 24.

It is a nocturnal, solitary, strongly terrestrial and omnivorous animal, feeding on fruits, small vertebrates and invertebrates.

The brown four-eyed opossum builds nests made of leaves and twigs in tree branches or under rocks and logs.{{cite web | last = Bies | first = L. | title = Metachirus nudicaudatus | work = Animal Diversity Web | publisher = University of Michigan Museum of Zoology| year = 2002 | url = http://animaldiversity.ummz.umich.edu/site/accounts/information/Metachirus_nudicaudatus.html | access-date = 2012-01-13}} It is seasonally polyestrous and the litter size varies from one to nine.

The white spot over each eye inspired the common name of "four-eyed opossum". Its scaly tail is longer than its body.

The opossum is mostly insectivorous,{{cite journal|last=Cáceres|first=N.C.|title=Diet of three didelphid marsupials (Mammalia, Didelphimorphia) in southern Brazil|journal=Mammalian Biology|year=2004|volume=69|issue=6|pages=430–433|doi=10.1078/1616-5047-00165|bibcode=2004MamBi..69..430C }} though it also consumes some types of fruit seeds, small vertebrates like birds and reptiles and invertebrates like crayfish and snails.{{cite book |last1=Gardner |first1=Alfred L.|last2=Dagosto|first2=Marian|chapter=Tribe Metachirini Reig, Kirsch, and Marshall, 1985|title=Mammals of South America|volume=1|publisher=University of Chicago Press|pages=35–39|isbn=978-0-226-28240-4|year=2007|editor-last=Gardner|editor-first=Alfred L.}} The brown four-eyed opossum is a host of the acanthocephalan intestinal parasite Gigantorhynchus ortizi.{{cite journal |last1=Nascimento Gomes |first1=Ana Paula |last2=Cesário |first2=Clarice Silva |last3=Olifiers |first3=Natalie |last4=de Cassia Bianchi |first4=Rita |last5=Maldonado |first5=Arnaldo |last6=Vilela |first6=Roberto do Val |title=New morphological and genetic data of Gigantorhynchus echinodiscus (Diesing, 1851) (Acanthocephala: Archiacanthocephala) in the giant anteater Myrmecophaga tridactyla Linnaeus, 1758 (Pilosa: Myrmecophagidae) |journal=International Journal for Parasitology: Parasites and Wildlife |date=December 2019 |volume=10 |pages=281–288 |doi=10.1016/j.ijppaw.2019.09.008|pmid=31867208 |pmc=6906829 |bibcode=2019IJPPW..10..281N }}