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Metachirus nudicaudatusbrown four-eyed opossum

By LeeAnn Bies

Geographic Range

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

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).

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

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).

  • 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
    AnAge

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 polyestorus, November (Central America)
  • Range number of offspring
    1 to 9
  • Average number of offspring
    5
    AnAge

Lifespan / Longevity

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).

Communication and Perception

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

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

Contributors

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

Glossary

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

internal fertilization

fertilization takes place within the female's body

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

scrub forest

scrub forests develop in areas that experience dry seasons.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

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.

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