White-bellied woolly mouse opossum
White-bellied woolly mouse opossum (Marmosa constantiae) is a small pouchless marsupial in the Didelphidae family. It used to be placed in the Micoureus group, which became part of Marmosa in 2009. The species name honors Constance Sladen, who funded the expedition that collected the first specimen in 1902.
What it looks like:
- One of the larger mouse opossums: head and body 11–18 cm; tail 15–23 cm; weight 35–144 g.
- Thick, woolly fur that is grey on most of the body and buffy-yellow on the head and underparts.
- Narrow black rings around the eyes.
- Tail is furred at the base; near the body it is dark, turning pale pink toward the end.
- Broad feet with strong claws and toe ridges that help in climbing.
Females do not have a pouch but have 15 teats arranged in a circle—the most among close relatives. They appear to breed year-round, and mothers have been found with up to seven young.
Where it lives:
- Range includes northern Bolivia, Brazilian states of Mato Grosso and Mato Grosso do Sul, northern Argentina up to Tucumán, and recently Paraguay.
- Inhabits moist tropical forests, often near drier areas, from sea level up to about 1,000 meters in elevation.
- It is arboreal (lives in trees), solitary, and nocturnal, spending most time in the forest understory.
What it eats:
- Omnivorous: mainly insects (especially bugs) and plant material.
Conservation:
- The species is listed as Least Concern, meaning it is not currently at high risk of extinction.
This page was last edited on 2 February 2026, at 21:16 (CET).