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Glironia venustabushy-tailed opossum

By Leila Siciliano Martina

Geographic Range

Bushy-tailed opossums (Glironia venusta) are found in South America’s Amazon and Paraguay Basins; they are extremely rare and monotypic within their genus. Populations have been documented in 17 localities from Ecuador, Peru, Brazil and Bolivia; there have also been unconfirmed reports of this animal in Columbia. There is still much to learn of their range and distribution; these arboreal animals are likely canopy-dwellers, which makes population sampling difficult. Knowledge of this species is based on very few specimens and observations. (Barkley, 2008; Calzada, et al., 2008; Fantin and da Silva, 2011; Nowak, 2005; Patterson and Solari, 2012; Rossi, et al., 2010; Santos-Filho, et al., 2007)

Habitat

Bushy-tailed opossums likely dwell in the canopy, although they have been observed low in the forest and attempts to live-trap the animals in the forest understory have been successful. They have been found exclusively within forests, no closer than 3 kilometers to human settlements. They have been captured in dense, humid, semi-deciduous and sub-montane forests at up to 500 m in elevations. These animals have been observed moving quickly through hanging vines in the canopy, about 15 m above ground. (Calzada, et al., 2008; Fantin and da Silva, 2011; Marshall, 1978; Patterson and Solari, 2012; Rossi, et al., 2010; Santos-Filho, et al., 2007)

  • Range elevation
    500 (high) m
    1640.42 (high) ft

Physical Description

Bushy-tailed opossums are rare, medium-sized marsupials, weighing about 140 grams on average. These animals have a total body length of 355 to 430 mm, including a 190 to 225 mm tail. Dorsally, their long, thick fur varies between a woolly or velvety texture and is solid reddish-brown to gray, with fur lengths of 7 to 8 mm. This coloration extends throughout much of their tail, which may have sparse white hairs throughout and is generally tipped in white. These animals are similar in appearance to members of genus Marmosa, aside from the thick furring of their tail. Near the middle of their tail, their fur measures about 14 to 15 mm, giving them their namesake ‘bushy’ appearance. Their ventral pelage is brownish to grayish and tipped in white. Their head is lighter than their dorsal pelage and includes a brownish-black stripe that extends from their nose, to the base of the ears and up to the top of their head and is bisected by a pale gray stripe. Their large nasals expand posteriorly. Bushy-tailed opossums have large, oval-shaped ears that lack fur and are darkly colored. They have the same dental formula as other didelphids: 5/4, 1/1, 3/3, 4/4, with a total of 50 teeth. Their feet are light in coloration, from whitish to gray, with hind feet that measure 27 to 31 mm and an opposable hallux. These marsupials lack a pouch and have 5 mammae. (Barkley, 2008; Calzada, et al., 2008; Marshall, 1978; Nowak, 2005; Rossi, et al., 2010)

  • Average mass
    140 g
    4.93 oz
  • Range length
    355 to 430 mm
    13.98 to 16.93 in

Reproduction

There is no specific information regarding the mating systems of bushy-tailed opossums. However, members of family Didelphidae are generally considered polygynous. Males from studied species compete for reproductive females, communicating with a series of clicking noises. Generally, Didelphids show neither courtship displays nor pair bonds. (Fernandes, et al., 2010; O'Connell, 2006)

Bushy-tailed opossums do not have a pouch. Females have 5 mammae arranged in two abdominal pairs, with one additional teat in the middle. There is currently no information available regarding their reproductive behavior. (Barkley, 2008; Marshall, 1978)

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

Due to their rarity, very little research has been conducted on the parental behavior of bushy-tailed opossums; however, all studied didelphid species have extremely altricial young. Upon birth, the young climb to their mother’s mammae and remain for weeks, after which, young are often carried by their mothers until they are weaned several weeks later. (Emmons, 1990)

Lifespan/Longevity

The lifespan of bushy-tailed opossums has not been reported; however, opossums are generally short-lived, typically living no more than 1 to 2 years. (O'Connell, 2006)

Behavior

Very little is currently known of this extremely rare species, although they are believed to be nocturnal and solitary. Their long opposable halluces, as well as behavioral observations suggest that they are arboreal; however, their body structure also suggests that they might be found terrestrially as well. They have been observed running quickly on vines in the forest canopy, possibly while hunting insects. (Barkley, 2008; Fantin and da Silva, 2011; Marshall, 1978; Nowak, 2005; Patterson and Solari, 2012; Rossi, et al., 2010)

Home Range

The home range size of this species is currently unknown.

Communication and Perception

There is currently no information available specific to the communication and perception of bushy-tailed opossums. Didelphid species often have an acute sense of smell, which facilitates their travel to the mammae directly after birth. Generally, didelphids also have good eyesight and hearing, although the specific sensory functions of bushy-tailed opossums are not known. (O'Connell, 2006)

Food Habits

The diet of bushy-tailed opossums is currently not known, however, their similarities to genus Marmosa has led researchers to assume that they share a similar diet composed of insects, eggs, seeds and fruits. (Barkley, 2008; Nowak, 2005; Patterson and Solari, 2012)

  • Animal Foods
  • eggs
  • insects
  • Plant Foods
  • seeds, grains, and nuts
  • fruit

Predation

Predators of bushy-tailed opossums have not been reported. However, harpy eagles are known to prey on four-eyed opossums, which share a similar habitat and range. Likewise, their habitat is also occupied by a variety of felid species including ocelots, oncillas, margays, jaguars, cougars and jaguarundis, all of which may prey on bushy-tailed opossums. (Galetti and de Carvalho, 2000; Solari, et al., 2006)

Ecosystem Roles

Bushy-tailed opossums are assumed to have a diet similar to members of genus Marmosa. In that case, bushy-tailed opossums may also disperse seeds, similar to Robinson’s mouse opossums (Marmosa robinsoni). Bushy-tailed opossums are also known to carry ticks. (Need, et al., 1991; Nowak, 2005; Rojas-Robles, et al., 2012)

Commensal/Parasitic Species
  • ticks (Ixodes lagotis)

Economic Importance for Humans: Positive

There are no known positive economic impacts of bushy-tailed opossums.

Economic Importance for Humans: Negative

There are no known negative economic impacts of bushy-tailed opossums.

Conservation Status

Currently, bushy-tailed opossums are considered a species of least concern by the IUCN Red List of Threatened Species. Although this species has not been thoroughly studied, they are believed to be fairly widespread and are found in protected habitats. (Patterson and Solari, 2012)

Other Comments

The genus name Glironia refers to their physical similarity to rodents; ‘glir’ refers to dormice and the suffix ‘ia’ implies a quality. The species name ‘venusta’ means amiable or graceful. (Marshall, 1978)

Contributors

Leila Siciliano Martina (author), Animal Diversity Web Staff.

Glossary

Neotropical

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

World Map

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.

chemical

uses smells or other chemicals to communicate

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.

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.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

sexual

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

solitary

lives alone

tactile

uses touch to communicate

tropical

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

viviparous

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

References

Barkley, L. 2008. Genus Glironia. Pp. 12-14 in A Gardner, ed. Mammals of South America: Marsupials, Xenarthrans, Shrews, and Bats, Vol. 1. Chicago: University of Chicago Press.

Calzada, J., M. Delibes, C. Keller, F. Palomares, W. Magnusson. 2008. First record of the bushy-tailed opossum, Glironia venusta, Thomas, 1912, (Didelphimorphia) from Manaus Amazonas, Brazil. Acta Amazonica, 38:4: 807-810.

Emmons, L. 1990. Neotropical Rainforest Mammals: A Field Guide. Chicago: The University of Chicago Press.

Fantin, C., M. da Silva. 2011. The karyotype of a rare South American marsupial, the bushy-tailed opossum genus Glironia (Didelphimorphia: Didelphidae). Mastozoologia Neotropical, 18:1: 125-130.

Fernandes, F., L. Cruz, E. Martins, S. dos Reis. 2010. Growth and home range size of the gracile mouse opossum Gracilinanus microtarsus (Marsupialia: Didelphidae) in Brazilian cerrado. Journal of Tropical Ecology, 26:2: 185-192.

Galetti, M., O. de Carvalho. 2000. Sloths in the diet of a harpy eagle nestling in eastern Amazon. Wilson Bulletin, 112:4: 535-536.

Marshall, L. 1978. Glironia venusta. Mammalian Species, 107: 1-3.

Need, J., W. Dale, J. Keirans, G. Dasch. 1991. Annotated list of ticks (Acari: Ixodidae: Argasidae) reported in Peru: Distribution, hosts, and bibliography. Journal of Medical Entomology, 28:5: 590-597.

Nowak, R. 2005. Bushy-tailed opossum. Pp. 80 in R Nowak, ed. Walker's Marsupials of the World, Vol. 7 Ed. Baltimore: The Johns Hopkins University Press.

O'Connell, M. 2006. American Opossums. Pp. 808-813 in D MacDonald, S Norris, eds. The Encyclopedia of Mammals, Vol. 1. London: The Brown Reference Group.

Patterson, B., S. Solari. 2012. "Glironia venusta" (On-line). IUCN Red List of Threatened Species. Accessed June 21, 2013 at www.iucnredlist.org.

Rojas-Robles, R., F. Stiles, Y. Munoz-Saba. 2012. Frugivory and seed dispersal Oenocarpus batava palm (Arecaceae) in a forest from the Columbian Andes. Revista de Biologia Tropical, 60:4: 1445-1461.

Rossi, R., C. Miranda, T. Santos Junior, T. Semedo. 2010. New records and geographic distribution of the rare Glironia venusta (Didelphimorphia, Didelphidae). Mammalia, 74: 445-447.

Santos-Filho, M., M. da Silva, B. Costa, C. Bantel, C. Vieira, D. Silva, A. Franco. 2007. New records of Glironia venusta, Thomas, 1912 (Mammalia, Didelphidae), from the Amazon and Paraguay basins, Brazil. Mastozoologia Neotropical, 14:1: 103-105.

Solari, S., V. Pacheco, L. Luna, P. Velazco, B. Patterson. 2006. Mammals of the Manu Biosphere Reserve. Fieldiana Zoology, 110: 13-22.

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