Micoureus demerarae - Long-furred Wooly Mouse Opossum​

Physical Description:

Micoureus demerarae, known commonly as the long-furred wooly mouse opossum, is a small marsupial measuring 120-215 mm in head and body length, with a tail length of 170-270 mm. It ranges in weight from 50-230 g. Coloration of the upper parts of the body can include many shades of gray or brown while the belly is cream, buff, or yellow in color. There is typically a dark colored ring around the eye. The tail can either be uniformly colored, or can be bicolored as the body. Micoureus demerarae differs from the closely related genus Marmosa in three distinct ways. First, the fur extends at least 20 mm onto the tail, while in Marmosa, the tail is usually fur covered for less than 20 mm. Also Micoureus demerarae lacks a throat gland and has the superior border of the frontal bone of the skull projected as a ledge (Nowak 1999).

Distribution:

Micoureus demerarae is widely spread throughout South America, primarily found in the tropical rainforests. It can be found from Columbia to Northern Argentina. Studies suggest that the populations on the Atlantic coast may be a slightly different species than Amazonian population (Brito and Fernandez 2002).

Ontogeny and Reproduction:

Reproduction occurs during the rainy season. Breeding has not been reported during the winter dry season. Nests are built by the females and are open consisting of leaves that are transported through the use of their mouth and prehensile tail (Nowak 1999). Micoureus demerarae is a polygamous species. Female home ranges seldom overlap each other, but male home ranges can overlap with each other and overlap multiple female home ranges (Pires et al 1999). Females are first able to breed successfully at 6 months of age and can have up to 11 young per litter. They have been recorded to live up to 24 months of age (Brito and Fernandez 2002).

Ecology and Behavior:

     Micoureus demerarae is a solitary mammal when not breeding. They are mostly arboreal, but will travel to the ground on occasion. They are found in mature as well as secondary evergreen rainforests. They prefer areas with many palm trees with dense vine growth, but can also be found in open high forests (Brito and Fernandez 2002).

            The diet of Micoureus demerarae consists mostly of insects, but the diet can be supplemented with fruits. Because of this they can be classified as both insectivores as well as omnivores. They will search for food both in the trees and on the ground and will search at night being nocturnal (Nowak 1999)

Remarks:

Micoureus demerarae was for a long time considered to be a subgenus of Marmosa, though is now a genus of its own. Before it was given its own genus, it was known by the name Marmosa Cinerea (Nowak 1999)

Literature Cited:

Brito, Daniel, and A.S. Fernandez. 2002. Patch relative importance to metapopulation viability: The neotropical marsupial Micoureus demerarae as a case study.

Animal Conservation 5:45-51.

Nowak, M. Walker’s Mammals of the World. 6th Edition, Volume 1. 1999. John Hopkins University Press. 22-23.

Pires, Alexandra S., Fernando A.S. Fernandez, and Daniela de Freitas. 1999. Patterns of Space Use by Micoureus demerarae (Marsupialia: Didelphidae) In a Fragment of Atlantic Forest in Brazil. Mastozoología Neotropical; 6(1):39-45.

Reference written by Kevin Geer, Biology 378 (Mammalogy), University of Wisconsin – Stevens Point.  Edited by Christopher Yahnke. Page last updated August 8, 2005.