Geographic Range

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

Physical Description

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). Mass: 800 g (max). Length: .570 to .630 male larger.

Lifespan/Longevity

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

Ecosystem Roles

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

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). Foods eaten: fruit, small vertebrates and invertebrates, insects, and bird’s eggs.

Reproduction

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). Breeding season: seasonally polyestrous, November (Central America). Number Produced: 1 to 9 Sexual; internal; viviparous Polygynandrous (promiscuous), Young altricial; female parental care.

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). Nocturnal; solitary.

Habitat

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). Elevation: 700 m (max).

Tropical; forest, scrub forest.

Economic Importance for Humans

Positive

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

Negative

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

Conservation Status:

IUCN: No special status
U.S. ESA: No special status
U.S. MBTA: 1
CITES: No special status

References

Freitas, Simone R., Diego Astua De Moraes, Ricardo T. Santori and Rui 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, Rosana and Rui Cerqueria. 1995. Movement patterns of five species of small mammals in a Brazilian restinga. Journal of Tropical Ecology 11(4):671-677.

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

Hunsaker II, Don. 1977. Biology of Marsupials. Academic Press, New York. Nowak, Ronald M. 1997. “Walker’s Mammals of the World” (On-line), Available http://www.press.jhu.edu/books/walkers_mammals_of_the_world/special.html (Oct. 8, 2001)

Rodford, Kent H. and Jon F. Eisenburg. 1992. Mammals of the Neotropics.

University of Chicago Press, Chicago.

Acknowledgements

This article is reproduced with many thanks and acknowledgements to the author and the University of Michigan Animal Diversity Web and the Smithsonian Institute.

For more information please go to

http://animaldiversity.ummz.umich.edu

and http://www.si.edu

Reference written by Leeann Bies, Bio 451: Mammalogy sec 6 (Myers/Teeter)