Glironia venusta
bushy-tailed opossum

The geographic range of bushy-tailed opossums, Glironia venusta, is known from 9 specimens collected in South America; specifically in Bolivia, Ecuador, Peru, and eastern Brazil. The holotype was identified in 1912 by Oldfield Thomas, and the most recent specimen was captured in 1989. (Tarifa and Anderson, 1997)

All nine Glironia venusta specimens were located in upper or lower Amazonian rainforests from 300 to 1000 meters in elevation. Their morphology suggests that G. venusta is arboreal (Emmons and Feer 1990; Langguth and Da Silva 1989; Marshall 1978; Tarifa and Anderson 1997). Two additional individuals were observed by Emmons at Parque Nacional Manu in southeast Peru and northwest Bolivia in the Valle de Marchariapo in a dry forested area. Since no specimens were ever recovered from those areas, this is not considered a confirmed record of occurrence (Emmons and Feer 1990; Tarifa and Anderson). (Emmons and Feer, 1990; Langguth and Da Silva, 1989; Marshall, 1978; Tarifa and Anderson, 1997)

Bushy-tailed opossums are medium-sized opossums with a body length of 160 to 205 mm. The coat varies in coloration with a light cinnamon color dorsally and a grayish to white and orange tinged underside. On the head there are two broad black stripes forming a mask starting at the nose, over the eyes, and terminating at the top of the head. Separating these stripes is a gray bar running from the nose to the ears. The ears are 22 to 25 mm in length, naked and a brown/black color. Sexes seem to be similar in appearance. (Emmons and Feer, 1990; Langguth and Da Silva, 1989; Marshall, 1978; Tarifa and Anderson, 1997)

The tail of G. venusta is the feature used to distinguish this species from all other South American opossums. It is the only opossum with a tail that is fully furred on the top and sides, hence the common name, bushy-tailed opossum. The tail is longer than the body with a total length of 195 to 205 mm (Emmons and Feer 1990; Langguth and Da Silva 1989; Marshall 1978; Tarifa and Anderson 1997). The tail is similar in coloration to the body and most specimens have an obvious white tip on the tail, though the intensity of the white varies from a long swatch to just a few scattered hairs (Langguth and Da Silva 1989; Marshall 1978). Da Silva and Langguth (1989) noted that the underside of the tail has transverse lines that are slightly inflated, similar to a pad. The hallux is opposable as well, which suggests a primarily arboreal lifestyle (Marshall 1978). (Emmons and Feer, 1990; Langguth and Da Silva, 1989; Marshall, 1978; Tarifa and Anderson, 1997)

Bushy-tailed opossums have weak canines and weakly developed premolars and molars, except for an enlarged P2 and P3. The dentition looks most like a species of Caluromys or Caluromysiops. The dental formula is similar to other didelphids: 5/4:1/1:3/3:4/4=50 (Marshall 1978). One reference stated that the weight of a sub-adult male was 104 grams (Nogueira et al 1999), though no other weight records were found. (Marshall, 1978; Nogueira, et al., 1999)

No studies have reported observing more than one individual at a time, so no data is available on mating systems in this species. Little information is available on related species as well.

Bushy-tailed opossums are non-pouched marsupials, which may give some indication on their reproductive cycle. The only data collected and published was on a sub-adult specimen captured in Brazil. Noqueira et al. (1999) completed a study and comparison of different didelphid male reproductive organs. In their study, the G. venusta reproductive system most resembled one from the Caluromys genus by having two bulbo-urethral pairs instead of three, as in most other didelphids. (Marshall, 1978; Nogueira, et al., 1999)

No information on reproduction is available for G. venusta. There is also very little information on reproduction in closely related Caluromys species. Caluromys philander breeds several times each year, depending on resource availability and local conditions. Gestation periods are short, 24 days or less, and lactation occurs for up to 120 days. Bushy-tailed opossums have four mammae, which limits their litter size.

No data has been collected on parental investment in Glironia venusta. As in all marsupials, females have a short gestation and a longer lactation period.

No studies have been published about the lifespan of Glironia venusta. Closely related, Caluromys philander individuals have been known to live up to 5 years in captivity and 41 months in the wild.

Bushy-tailed opossums are presumed to be arboreal and nocturnal, otherwise little is known of their behavior. Closely related Caluromys species are solitary, non-territorial, and nest in tree hollows and leaf nests. (Emmons and Feer, 1990; Marshall, 1978)

Home ranges are not known in Glironia venusta.

Since individuals were collected several years apart and many kilometers apart, little is known about how Glironia venusta communicates. An examination of the skull shows that they have a non-specific auditory region and a long narrow rostrum (Marshall 1978). Like most mammals, they probably rely primarily on olfaction and hearing to navigate, find food, and avoid predation. These opossums have large eyes, indicating they may use vision extensively as well. (Marshall, 1978)

No studies have been conducted on food habits, but bushy-tailed opossums are likely to be omnivorous because they lack specialized dentition and because closely related opossums are also omnivorous. Caluromys philander individuals eat primarily fruit, nectar, and insects.

This aspect of their life history has not been studied. It is likely that arboreal snakes and nocturnal raptors, such as owls take bushy-tailed opossums. They probably escape predation primarily through their nocturnality, cryptic coloration, and avoidance.

Bushy-tailed opossums are rare and no ecosystem roles are known. They may help to pollinate the flowers and disperse the seeds of fruiting trees through eating fruit and nectar.

Since they are rarely seen or captured, no positive aspects are known.

There are no negative impacts of bushy-tailed opossums on humans.

The IUCN Red list states that bushy-tailed opossums are considered vulnerable because they have a severely fragmented habitat with a continuous decline in the amount of habitat available. The last assessment was in 1996.

Glironia venusta is not listed on CITES.

This species has also been known by the names Glironia aequatorialis and Glironia criniger. Glironia venusta literally means an elegant or charming dormouse. (Marshall, 1978)