Thylamys venustusbuff-bellied fat-tailed mouse opossum

Ge­o­graphic Range

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

Habi­tat

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)

  • Range elevation
    350 to 4000 m
    1148.29 to 13123.36 ft

Phys­i­cal De­scrip­tion

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)

  • Range length
    195 to 248 mm
    7.68 to 9.76 in
  • Average length
    222 mm
    8.74 in

Re­pro­duc­tion

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)

  • Parental Investment
  • altricial
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifes­pan/Longevity

No records of lifes­pan in this species are avail­able.

Be­hav­ior

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)

Home Range

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

Com­mu­ni­ca­tion and Per­cep­tion

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)

Food Habits

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)

Pre­da­tion

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.

  • Anti-predator Adaptations
  • cryptic

Ecosys­tem Roles

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.

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

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

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

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

Con­ser­va­tion Sta­tus

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

Con­trib­u­tors

Tom Gi­a­rla (au­thor), Uni­ver­sity of Min­nesota, Sharon Jansa (ed­i­tor), Amer­i­can Mu­seum of Nat­ural His­tory, Robert Voss (ed­i­tor), Amer­i­can Mu­seum of Nat­ural His­tory, Tanya Dewey (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

acoustic

uses sound to communicate

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.

arboreal

Referring to an animal that lives in trees; tree-climbing.

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

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.

insectivore

An animal that eats mainly insects or spiders.

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

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

nocturnal

active during the night

sedentary

remains in the same area

sexual

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

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

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

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

viviparous

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

Ref­er­ences

Braun, J., N. Pratt, M. Mares. 2010. Thy­lamys pal­lid­ior (Didel­phi­mor­phia: Didel­phi­dae). Mam­malian Species, 42(856): 90-98.

Gi­a­rla, T., R. Voss, S. Jansa. 2010. Species Lim­its and Phy­lo­ge­netic Re­la­tion­ships in the Didel­phid Mar­su­pial Genus Thy­lamys Based on Mi­to­chon­dr­ial DNA Se­quences and Mor­phol­ogy. Bul­letin of the Amer­i­can Mu­seum of Nat­ural His­tory, 346: 1-67.

Palma, R. 1997. Thy­lamys el­e­gans. Mam­malian Species, 572: 1-4.