Thylamys tateiTate's fat-tailed mouse opossum

Geographic Range

Museum records of this species are sparse. Presently, Thylamys tatei appears to be restricted to the provinces of Ancash and Lima in Peru. (Giarla, et al., 2010)


This species has been recorded in mountainous and desert habitats in a small part of central Peru. It has been captured from 300 to 3000 meters above sea level. (Giarla, et al., 2010)

  • Range elevation
    300 to 3000 m
    984.25 to 9842.52 ft

Physical Description

Like other members of its genus, Thylamys tatei 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 white ventral region. This species is broadly similar to other members of the Elegans Group (which includes T. elegans, T. pallidior, and T. tatei) as described by Giarla et al. (2010). A single specimen of this rare species examined by Giarla et al. (2010) was recorded with a head + body lengths of 109 mm and tail length of 118 mm. (Giarla, et al., 2010)

  • Average length
    227 mm
    8.94 in


Little is known about the mating system in Thylamys tatei. For the closely related species Thylamys elegans, Palma (1997) reported that two adults have never been found in the same nest, suggesting that this species does not form monogamous breeding pairs. (Palma, 1997)

Little is known about the reproductive behavior of this species. No records of its behavior have been published.

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • viviparous

Little is known about parental investment in Thylamys tatei. 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


No record of this species' lifespan is available.


No published accounts of the behavior of Thylamys tatei are available. This species is likely solitary, as most small, insectivorous mammals are. As is the case for other members of this genus, Thylamys tatei is likely nocturnal and experiences daily torpor. Individuals of the closely related species Thylamys elegans build nests out of hair and leaves in rocks, trees, and abandoned rodent burrows (Palma 1997). (Palma, 1997)

Home Range

The home range of this species is not known.

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 tatei likely consumes insects and perhaps occasionally eats small vertebrates, leaves, fruit, seeds, and carrion (Palma 1997). (Palma, 1997)


Like other small mammals, Thylamys tatei is likely well adapted to avoiding predators by being nocturnal and inconspicuous. No records of known predators are available. (Giarla, et al., 2010)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

Thylamys tatei 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 tatei is not presently available. (Palma, 1997)

Economic Importance for Humans: Positive

There are no known positive impacts of Thylamys tatei on humans.

Economic Importance for Humans: Negative

There are no known negative effects of Thylamys tatei.

Conservation Status

There is not enough data to properly evaluate the conservation status of Thylamys tatei. As such, it is listed as "Data Deficient" by the IUCN.


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.



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

World Map


uses sound to communicate


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.


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.


an animal that mainly eats meat


uses smells or other chemicals to communicate


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.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.


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


An animal that eats mainly insects or spiders.


having the capacity to move from one place to another.


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.


active during the night


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


lives alone


uses touch to communicate


Living on the ground.


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


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


uses sight to communicate


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


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.