Caluromysiops irrupta

Geographic Range

Black-shouldered opossums ( Caluromysiops irrupta ) are considered one of the most poorly studied large members of family Didelphidae . They are known from very few specimens, although several animals have been captively housed in zoos. They have a patchy distribution in South America encompassing southeastern Columbia, southeastern Peru and western Brazil; although their range may extend into Bolivia as well.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Black-shouldered opossums are found at relatively low elevations, typically below 700 m, in the upper levels of mature bamboo and humid rainforests. These animals are occasionally seen within the mid-level of the forest, but rarely venture any lower.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• rainforest rainforest

Physical Description

Black-shouldered opossums are fairly large didelphids , with a head and body length of 250 to 330 mm and a tail length of 310 to 340 mm. Their body mass is known from a captured male who weighed 445 grams, although it is not known whether this is an average weight or if sexual dimorphism is present in the species. Their long, dense, soft dorsal pelage has a grayish-brown hue, with black fur patches that extend down their shoulders. This stripe continues down their front legs to their wrists and down their back, in two lines that run along their spine blending into the rest of their fur as it extends towards their rump. Their head is grayish-brown, with faint dusky lines. Their cheeks are buffy and they may have brownish spots between their eyes and their pink nose. They have long, blade-like canines and large molars. Their round ears are bright yellow on the inside. These animals also have furry tails. Aside from bushy-tailed opossums , black-shouldered opossums are the only didelphids with fur extending into the unpigmented portion of their tail. The majority of an adult’s tail is cream colored, although it is dark gray at the base and whitish at the hairless tip (the final 15 to 20 mm). Juvenile black-shouldered opossums have fully furred tails, but are otherwise very similar in appearance to their adult counterparts. This species also has well-developed pouches.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

Reproduction

There is currently very little information available regarding the mating systems of black-shouldered opossums. However, members of family Didelphidae are generally considered polygynous. Males from studied species compete for reproductive females. Generally, didelphids show neither courtship displays nor pair bonds.

The reproductive behavior of black-shouldered opossums is not well known. As in all known didelphids , their gestation period is likely very short, lasting no more than a couple of weeks, after which, tiny offspring are born and crawl immediately into their mother’s pouch. Female black-shouldered opossums are known to have very well-developed pouches. Specific breeding intervals are not known for this species; however, females with young have been documented in July and August through transactions with animal dealers. In such situations, only 2 young were noted per female.

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

There is currently no information available regarding the parental investment of black-shouldered opossums specifically. However, in general didelphids remain in their mother’s pouch for several weeks, after which, female didelphids often carry their young on their back for several additional weeks, during which time, the young continue nursing.

• Parental Investment
• altricial altricial
• female parental care female parental care

Lifespan/Longevity

The lifespan of wild black-shouldered opossums is currently not known. However, the oldest captive individual survived for 7 years and 10 months.

Behavior

Black-shouldered opossums are known as slow-moving, nocturnal and solitary marsupials. These arboreal animals are typically found high in the tree canopy and may spend hours feeding on the nectar of an individual flower. Black-shouldered opossums are rarely seen outside of trees or below the forest’s mid-level and are often observed sitting motionless.

• Key Behaviors
• arboreal arboreal
• nocturnal nocturnal
• motile motile
• solitary solitary

Home Range

There is currently no information available regarding the home range size of black-shouldered opossums.

Communication and Perception

There is currently very little information available regarding the communication and perception of black-shouldered opossums. Although these animals may produce vocalizations, currently, no vocalizations have been detected in field studies. Olfaction is important for most marsupials as it facilitates their trip to their mother’s pouch directly after birth. Generally, didelphids also have good eyesight and hearing, although the specific sensory functions of black-shouldered opossums are not known.

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

This species’ diet is poorly known. These animals feed on nectar of South American sapote ( Quararibea cordata ) flowers, specifically during the dry season. It is likely that these animals also feed on fruits. In captivity they are also known to eat small vertebrates.

• Primary Diet
• omnivore omnivore

• Plant Foods
• fruit
• nectar

Predation

Currently, predators of black-shouldered opossums are not known. However, a variety of felid species also occupy their habitat including ocelots , oncillas , margays , jaguars , cougars and jaguarundis , all of which may prey on black-shouldered opossums. Likewise, the characteristically slow movement of this species may leave them vulnerable to a variety of predators, specifically when they are juveniles.

Ecosystem Roles

There is currently very little known about the ecosystem roles played by black-shouldered opossums. However, due to their careful feeding on the nectar of South American sapote ( Quararibea cordata ) flowers, these animals are believed to act as pollinators.

• Ecosystem Impact
• pollinates

Economic Importance for Humans: Positive

There are currently no known economic benefits of black-shouldered opossums on human populations. However, these animals have reportedly been involved in the pet trade and they have been displayed captively in several zoos.

• Positive Impacts
• pet trade pet trade

Economic Importance for Humans: Negative

There are currently no known economic drawbacks of black-shouldered opossums on human populations.

Conservation Status

Currently, black-shouldered opossums are listed as a species of least concern according to the IUCN Red List of Threatened Species. These animals are fairly widespread and some of their range is protected, specifically within their Peruvian range. However, their Brazilian range may be experiencing habitat destruction.

Other Comments

Prior to being placed in family Didelphidae , black-shouldered opossums were in the now defunct family Caluromyidae with the genera Caluromys and Glironia . Although these animals have been poorly studied since their discovery in 1951, they have been captively housed in several zoos including Oklahoma City Zoo, Lincoln Park Zoo, Brookfield Zoo, Tarpon Springs Zoo and Cincinnati Zoo.

Additional Links

Encyclopedia of Life

Contributors

Leila Siciliano Martina (author), Texas State University.

References

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Emmons, L. 1990. Neotropical rainforest mammals: A field guide . Chicago: The University of Chicago Press.

Emmons, L. 2008. Genus Calyromysiops . Pp. 11-12 in Mammals of South America: Marsupials, Xenarthrans, Shrews, and Bats , Vol. 1. Chicago: University of Chicago Press.

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.

Izor, R., R. Pire. 1987. Notes on the black-shouldered opossum, Caluromysiops irrupta . Fieldiana Zoology , 39: 117-124.

Janson, C., J. Terborgh, L. Emmons. 1981. Non-flying mammals as pollinating agents in the Amazonian forest. Biotropica , 13:2 Supp: 1-6.

Nowak, R. 2005. Walker's Marsupials of the World . Baltimore: The John's Hopkins University Press.

O'Connell, M. 2006. American opossums. Pp. 808-813 in The Encyclopedia of Mammals , Vol. 1. London: The Brown Reference Group.

Palma, R. 2003. The evolution of American marsupials and their phylogenetic relationship to Australasian metatherian. Pp. 21-29 in Carnivores with pouches: The biology of carnivorous marsupials , Vol. 1. Australia: Csiro Publishing.

Patterson, B., S. Solari. 2008. " Caluromysiops irrupta " (On-line). IUCN Red List of Threatened Species. Accessed June 20, 2013 at www.iucnredlist.org .

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