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Metachirus nudicaudatus
brown four-eyed opossum


By LeeAnn Bies

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Didelphimorphia
Family: Didelphidae
Genus: Metachirus
Species: Metachirus nudicaudatus

Geographic Range

Metachirus nudicaudatus, brown four eyed opossums, range from Nicaragua to Paraguay and N. Argentina (Redford and Eisenburg, 1992).

Biogeographic Regions
neotropical (Native )

Habitat

Range elevation
700 (high) m
(2296.59 (high) ft)

Brown four eyed opossums are both arboreal and terrestrial, but more often are found on the ground. They inhabit lowlands, heavy forests, or open brush country. They build round nests in tree branches or at times under rocks and logs (Hunsaker, 1977). The nests are made of leaves and twigs (Nowak, 1997).

Habitat Regions
tropical

Terrestrial Biomes
forest ; scrub forest

Physical Description

Range mass
800 (high) g
(28.19 (high) oz)

Range length
.570 to .630 m
(1.87 to 2.07 ft)

Average basal metabolic rate
1.144 W
[External Source: AnAge]

In general, M. nudicaudatus is grayish-brown in color. The back and sides are darker brown. The head has a dark band stretching from the tip of the snout over the eyes and across the base of the ear, making the face look almost black. In some individuals, this band extends past the ears. The eyes are large, rounded, and completely dark. A creamy white spot over each eye gives the animals their "four-eyed" name. The fur is short, thick, and silky. The venter (belly or abdomen) is usually white or cream. The tail is furred partially near the base. The rest of the tail, the scaly part, is multicolored--part black and part white. The length of the tail is usually around 330 mm, being longer than the body which is about 265 mm (Nowak, 1997; Redford and Eisenburg, 1992). The females are 71% lighter than the males (Hansen et al., 1999).

Other Physical Features
endothermic ; bilateral symmetry

Reproduction

Mating System
polygynandrous (promiscuous)

Breeding season
seasonally polyestorus, November (Central America)

Range number of offspring
1 to 9

Average number of offspring
5
[External Source: AnAge]

Brown four eyed opossums are seasonally polyestrous, meaning that they are capable of breeding many times through out the year. In Central America, though, they are reported to breed in November. The female of this species does not have a pouch like most marsupials. Instead lateral folds of skin exist on the lower abdomen, on which the mammae are located (females with 5, 7, and 9 have all been recorded). Therefore, the young does not crawl into the pouch after birth like other marsupials. A 51-mm young was reported to be capable of standing on its own. It rode on its mother's hips or back and was fully independent 2 months later (Nowak, 1997).

Key Reproductive Features
gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous

Parental Investment
altricial ; female parental care

Lifespan/Longevity

Range lifespan
Status: wild

3-4 (high) years

Average lifespan
Status: captivity

4.0 years
[External Source: Max Planck Institute for Demographic Research]

The maximum lifespan of M. nadicaudatus is three to four years (Nowak, 1997)

Behavior

Brown four eyed opossums are completely nocturnal, hardly moving from their nests until dark. In a capture-mark-recapture study over two years, M. nudicaudatus was found to be highly mobile and exploratory. It also had a short residence time. It has been observed that when M. nudicaudatus is held in the hand it hardly makes any noise (Nowak, 1997; Gentile and Cerquiera, 1995).

Key Behaviors
nocturnal ; solitary

Food Habits

This species is mainly frugivorous. However, their diet can also include insects, bird's eggs, small vertebrates such as reptiles, and also small invertebrates (Hunsaker, 1977). In a study which examined the feces of individuals, some brown four eyed opossums were found to consume more ants, termites, cockroaches and beetles than any other food in their diet (Freitas et al., 1997).

Animal Foods
amphibians; eggs; insects

Plant Foods
fruit

Ecosystem Roles

As an insectivore, M. nudicaudatus clearly helps to keep the numbers of insects in its habitat under control (Freitas et al., 1997).

Ecosystem Impact
disperses seeds

Economic Importance for Humans: Positive

Brown four eyed opossums consume pests such as ants, termites, and cockroaches (Frietas et al., 1997).

Positive Impacts
controls pest population

Economic Importance for Humans: Negative

This species has been accused of destroying fruit crops in certain areas (Nowak, 1997).

Negative Impacts
crop pest

Conservation Status

IUCN Red List [Link]
Lower Risk - Least Concern

US Federal List [Link]
No special status

CITES [Link]
No special status

For More Information

Find Metachirus nudicaudatus information at

Contributors

LeeAnn Bies (author), University of Michigan, Kate Teeter (editor), University of Michigan.

References

Freitas, S., D. Moraes, R. Santori, R. Cerqueira. 1997. Habitat preference and food use by Metachirus nudicaudatus and Didelphis aurita in a restinga forest at Rio de Janeiro. Revista Brasileira de Biologia, 57(1): 93-98.

Gentile, R., R. Cerqueria. 1995. Movement patterns of five species of small mammals in a Brazilian restinga. Journal of Tropical Ecology, 11(4): 671-677.

Hansen, R., J. Vie, N. Vidal, J. Kervac. 1999. Body measurements on 40 species of mammals from French Guiana. The Zoological Society of London, 247: 419-428.

Hunsaker II, D. 1977. Biology of Marsupials. New York: Academic Press.

Nowak, R. 1997. "Walker's Mammals of the World" (On-line). Accessed Oct. 8, 2001 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/special.html.

Rodford, K., J. Eisenburg. 1992. Mammals of the Neotropics. Chicago: University of Chicago Press.

To cite this page: Bies, L. 2002. "Metachirus nudicaudatus" (On-line), Animal Diversity Web. Accessed February 12, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Metachirus_nudicaudatus.html

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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