Thylamys venustus
buff-bellied fat-tailed mouse opossum

Thylamys venustus is distributed at low- to mid-elevations in the Andes from Central Bolivia southward into northern Argentina. (Giarla, et al., 2010)

Thylamys venustus primarily inhabits mid-level montane forests and seasonally dry forests between 350 and 4000 meters above sea level in the eastern Andes. This species overlaps in distribution with Thylamys sponsorius, Thylamys pallidior, and Thylamys pusillus. (Giarla, et al., 2010)

Like other members of its genus, Thylamys venustus is notable for its incrassate (fattened) tail. The size of the tail varies by season in accordance with food availability. Although this species is a marsupial, females do not have a pouch. This species is tricolored, with darker dorsal fur, paler lateral fur, and a grayish ventral region. This species is very similar in morphology to its sister species Thylamys sponsorius, though it tends to be slightly smaller. Like Thylamys sponsorius, this species has a relatively long tail that is considerably longer than its body. Giarla et al. (2010) report head and body lengths that range from 84 to 110 mm (average 96 mm) and tail lengths that range from 111 to 138 mm long (average 126 mm). (Giarla, et al., 2010)

Little is known about the mating system in Thylamys venustus.

Little is known about the general reproductive behavior of Thylamys venustus.

Little is known about parental investment in Thylamys venustus. Like all marsupials, females nurse their highly altricial young. However, because members of the genus Thylamys lack a pouch (marsupium), the young must cling to their mother's venter. (Giarla, et al., 2010)

No records of lifespan in this species are available.

Little is known about the behavior of Thylamys venustus. This species is likely solitary, as most small, insectivorous mammals are. As is the case for other members of this genus, Thylamys venustus is nocturnal and experiences daily torpor. Like other members of the genus Thylamys, individuals likely build nests out of grass, hair, feathers, and leaves in rocks, trees, and under shrubs (Braun et al., 2010). Thylamys species are primarily terrestrial but are also skilled at climbing bushes and small trees. (Braun, et al., 2010; Giarla, et al., 2010)

No data on the home range of this species are available.

Because this species is small and nocturnal, communication between individuals is likely primarily olfactory in nature. Palma (1997) reports that the olfactory and visual regions of another Thylamys species' brain are especially well developed. (Palma, 1997)

Little is known about the food habits of this species. Like other Thylamys species, Thylamys venustus likely consumes insects and perhaps occasionally eats small vertebrates, leaves, fruit, seeds, and carrion (Palma 1997). (Palma, 1997)

Like other small mammals, Thylamys venustus is likely well adapted to avoiding predators by being nocturnal and inconspicuous. No records of known predators are available.

Thylamys venustus likely acts as an important predator to many arthropod species and perhaps some small vertebrates. It is likely prey to both bird and medium-sized mammals, such as owls and foxes. It is also likely host to many ecto- and endoparasites. More specific information about the ecosystem role of Thylamys venustus is not presently available.

There are no known positive effects of Thylamys venustus on humans.

There are no known negative effects of Thylamys venustus on humans.

This species is listed as "Data Deficient" by the IUCN.