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Monodelphis brevicaudatared-legged short-tailed opossum

By Aarti Mandavia

Geographic Range

Monodelphis brevicaudata is predominantly found in the South American countries of Venezuela, the Guyanas, Columbia, parts of Brazil, and Bolivia. (NatureServe, 2003; Ventura, et al., 1998)

Habitat

Red-legged short-tailed opossums live mainly in forests and in shrubby areas with a great deal of vegetation. Nests have been reported in the hollows of trees. (Eisenberg and Redford, 1999; Linares, 1998)

Physical Description

Red-legged short-tailed opossums have a body length of approximately 16 cm, a tail length of roughly 9 cm, and weigh between 67 and 95 g. Males are reported to be slightly larger than females.

One distinctive feature of M. brevicaudata is that members of the species usually have grey or black fur on their backs, reddish fur on their sides continuing onto the legs, and black feet and tail. Their tails are very short and furred. Their fur is usually short and dense.

The skull is characterized by the presence of the jugal and zygomatic arch. The dental formula of this opossum species is 5/4, 1/1, 3/3, 4/4= 50. (Eisenberg and Redford, 1999; Engstrom, et al., 1999; Wible, 2003)

  • Sexual Dimorphism
  • male larger
  • Range mass
    67 to 95 g
    2.36 to 3.35 oz
  • Average length
    16 cm
    6.30 in
  • Average basal metabolic rate
    0.366 W
    AnAge

Reproduction

There is relatively little known about the mating patterns of M brevicaudata in particular. It may be similar to that of other didelphids, which are polygynous. Competition between males may be extreme, and male opposums are often intollerant of one another. Because of the sexual dimorphism in size seen in this species, it is likely that they are similar to other members of their family. (Cockrum, 1962; Linares, 1998; Nowak, 1997)

There is not a great deal that is known about the reproduction of the M. brevicaudata. Although data for this species are scant, within one member of the genus the period of estrus was found to last 3 to 12 days, and the estrous cycle showed a bimodal distribution, being about 2 weeks long in one of captive females and about 1 month long in another group. The species usually reproduces during the dry season and they produce between 6 and 8 young. Reproduction of this species may be similar to that of other opossums which have an average gestation period of 12.5 days. (Cockrum, 1962; Cockrum, 1962; Linares, 1998)

Regardless of the actual length of gestation, we can assume that because these animals are marsupials, the gestation is short, and the young are born fairly undeveloped. Because the pouch of females is not well developed in this genus, it is likley that the young must cling to the nipple until they are large enough to ride on the back of their mother. (Nowak, 1997)

Young are dependent upon their mother until about 50 days after birth. Sexual maturity in the genus Monodelphis is reached between 4 and 5 months of age, and breeding may occur as late as 39 months of age in males and 28 months in females. (Nowak, 1997)

It is not known how frequently these animals reproduce, and it is not possible to generalize from other members of the genus. Some species in Monodelphis are apparently semelparous, with few individuals living past their first reproduction. Others may produce up to four litters per year. (Nowak, 1997)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • viviparous
  • Breeding interval
    The breeding interval of these animals is not known.
  • Breeding season
    The breeding season of this species has not been reported.
  • Range number of offspring
    6 to 8
  • Average number of offspring
    7
    AnAge
  • Average time to independence
    50 days
  • Range age at sexual or reproductive maturity (female)
    4 to 5 months
  • Range age at sexual or reproductive maturity (male)
    4 to 5 months

There is no information about the specific parental investment of red-legged, short-tailed opossums. It is likely that the female, who provides nourishment for the young gives most, if not all of the parental care. The pouch of these animals is reported to be poorly developed, and so the young must cling to a nipple until they are large enough to ride on the the mother's back. The role of the male in parental care of M. bevicaudata is not known. (Nowak, 1997)

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

The lifespan of M. brevicaudata is unknown.

  • Average lifespan
    Status: captivity
    3.9 years
    AnAge

Behavior

Behavior of M. brevicaudata is still being explored. However, it is know that these mammals are solitary and usually asocial creatures. It is also known that they are diurnal, territorial and terrestrial. They are motile on the ground and occasionally in trees. (Eisenberg and Redford, 1999; Linares, 1998)

Home Range

The home range size for these animals has not been reported.

Communication and Perception

Details of the communciation patterns of M. brevicaudata are not available. The species is reported to have tactile and chemical perception channels. As diurnal mammals, we can assume that they also use vision to some extent, and it is likely that they communicate with one another using body postures and other visual signals. Vocalizations have not been reported, but probably occur.

Food Habits

Red-legged short-tailed opossums generally eat insects such as cockroaches and crickets and small animals such as spiders, but also eat fruit and seeds on occasion. (Linares, 1998)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • fruit

Predation

Details on the predation of M. brevicaudata are unknown, but common didelphid predators include owls, coyotes, foxes, and bobcats.

Ecosystem Roles

Through its foraging behavior, M. brevicaudata probably has a role in the regulation of insects and small animal populations in its habitat. To the extent that these animals serve as prey for predators, they may also have some affect on predator populations.

Economic Importance for Humans: Positive

There are no known positive effects of this species on humans.

Economic Importance for Humans: Negative

There are no known negative consequences of this species on humans.

Conservation Status

There is no special conservation status for M. brevicaudata. Howver,there are reportes that most members of the genus are declining due to habitat destruction. (Nowak, 1997)

Contributors

Nancy Shefferly (editor), Animal Diversity Web.

Aarti Mandavia (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, 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

diurnal
  1. active during the day, 2. lasting for one day.
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.

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.

native range

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

polygynous

having more than one female as a mate at one time

scrub forest

scrub forests develop in areas that experience dry seasons.

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.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

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

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

Cockrum, E. 1962. Introduction to Mammology. New York: The Ronald Press Company.

Eisenberg, J., K. Redford. 1999. Mammals of the Neotropics-Volume 3. Chicago and London: The University of Chicago Press.

Engstrom, M., B. Lim, F. Reid. 1999. "Iwokrama Mammals- Opossums. Short-tailed Opossum." (On-line). Accessed February 08, 2004 at http://iwokrama.org/mammals/frame.html.

Linares, O. 1998. Mamiferos de Venezuela. Caracas: Socieda Conservacionista Audubon de Venezuela.

NatureServe, 2003. "Didelphis brevicaudata: Red-legged, short-tailed opossum." (On-line). InfoNatura: Birds, mammals, and amphibians of Latin America. Accessed February 09, 2004 at http://www.natureserve.org/infonatura/.

Nowak, R. 1997. "Monodelphis: Short-tailed opossums" (On-line). Walker's Mammals of the World, On-Line. Accessed March 07, 2004 at http://www.press.jhu.edu/books/walkers_mammals_of_the_world/marsupialia/marsupialia.didelphidae.monodelphis.html.

Ventura, J., R. Perez-Hernandez, M. Lopez-Fuster. 1998. Morphometric Assessment of the Monodelphis brevicaudata Group in Venezuela. Journal of Mammalogy, 79/1: 104-111.

Wible, J. 2003. "The Bones of the Skull of the Short-tailed Opossum, Monodelphis brevicaudata (Didelphidae, Marsupialia)" (On-line). Accessed February 08, 2004 at http://www.carnegiemnh.org/mammals/publications/opossum.doc.

Wilson, D., D. Reeder. 1993. "Mammal Species of the World (MSW) Scientific Names" (On-line). Accessed February 07, 2004 at http://nmnhgoph.si.edu/msw/.

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