Geographic Range
Thylamys elegans
appears to be restricted to central Chile, but further surveys are needed to determine
the limits of its distribution (Giarla et al., 2010).
- Biogeographic Regions
- neotropical
Habitat
Thylamys elegans
primarily inhabits the Chilean Matorral, an ecoregion characterized by a Mediterranean
climate and sclerophyllous vegetation. The Atacama desert lies to the north of the
Matorral, and
Thylamys elegans
might inhabit parts of this habitat as well.
- Habitat Regions
- temperate
- terrestrial
- Terrestrial Biomes
- desert or dune
- chaparral
- scrub forest
Physical Description
Like other members of its genus,
Thylamys elegans
is notable for its incrassate (fattened) tail. The size of the tail varies by season
in accordance with food availability. This species is tricolored, with darker dorsal
fur, paler lateral fur, and a cream-colored ventral region. Giarla et al. (2010) report
body lengths of 90 to 127 mm, with tails 105 to 134 mm long. Although this species
is a marsupial, females do not have a pouch (Palma, 1997). Bozinovic et al. (2005)
report a basal metabolic rate of 1.07 mL oxygen per gram-hour-ºC
- Other Physical Features
- endothermic
- bilateral symmetry
Reproduction
Little is known about the mating system in
Thylamys elegans
. Palma (1997) reports that two adults have never been found in the same nest, suggesting
that this species does not form monogamous breeding pairs.
Breeding season for
Thylamys elegans
occurs from September through March, with females having one or two litters per season.
Up to 17 embryos have been reported, but survival is limited by the number of functional
nipples on the female, which is typically 11 to 13 (Palma, 1997).
- Key Reproductive Features
- iteroparous
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
Little is known about parental care in
Thylamys elegans
. Like other
Thylamys
species, females lack a pouch and exposed young cling to the nipples.
- Parental Investment
- altricial
- female parental care
-
pre-fertilization
- provisioning
-
protecting
- female
-
pre-hatching/birth
-
provisioning
- female
-
protecting
- female
-
provisioning
-
pre-weaning/fledging
-
protecting
- female
-
protecting
Lifespan/Longevity
No published records of lifespan exist for this species.
Behavior
Little is known about the behavior of
Thylamys elegans
. This species is likely solitary, as most small, insectivorous mammals are. As is
the case for other members of this genus,
Thylamys elegans
is nocturnal and experiences daily torpor. Individuals build nests out of hair and
leaves in rocks, trees, and abandoned rodent burrows (Palma 1997).
Home Range
In winter, the home range of
Thylamys elegans
was estimated to be approximately 1,400 square meters. In summer, this species' home
range is smaller and estimated to be approximately 800 square meters.
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 this species' brain are especially well developed.
Food Habits
Like other
Thylamys
species,
Thylamys elegans
primarily consumes insects, although it occasionally eats small vertebrates, leaves,
fruit, seeds, and carrion (Palma 1997).
- Primary Diet
- carnivore
- Animal Foods
- birds
- mammals
- amphibians
- reptiles
- carrion
- terrestrial non-insect arthropods
- Plant Foods
- leaves
- seeds, grains, and nuts
- fruit
Predation
Like other small mammals,
Thylamys elegans
is likely well adapted to avoiding predators by being nocturnal and inconspicuous.
- Anti-predator Adaptations
- cryptic
Ecosystem Roles
Thylamys elegans
acts as an important predator of many arthropod species and some small vertebrates.
It is prey to several bird and medium-sized mammals, such as owls and foxes. It is
likely host to many ecto- and endoparasites. More specific information about the ecosystem
role of
Thylamys elegans
is not presently available.
Economic Importance for Humans: Positive
This species likely has little direct impact on humans.
Economic Importance for Humans: Negative
This species likely has little direct impact on humans.
Conservation Status
Thylamys elegans is considered "least concern" by the IUCN.
Additional Links
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.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- temperate
-
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
- terrestrial
-
Living on the ground.
- 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.
- chaparral
-
Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.
- scrub forest
-
scrub forests develop in areas that experience dry seasons.
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- seasonal breeding
-
breeding is confined to a particular season
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- 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.
- female parental care
-
parental care is carried out by females
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- carrion
-
flesh of dead animals.
- 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.
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- 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.
- 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.
References
Bozinovic, F., G. Ruiz, A. Cortes, M. Rosenmann. 2005. Energetics, thermoregulation and torpor in the Chilean mouse-opossum Thylamys elegans (Didelphidae). Revista Chilena de Historia Natural , 78: 199-206.
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.