Didelphis imperfecta

Geographic Range

Guianan white-eared opossums ( Didelphis imperfecta ) are found in northern to central South America. This species is endemic to Guyana, Suriname, French Guiana, Venezuela and Brazil, however, they are likely also found in western Ecuador and northeastern Peru.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Guianan white-eared opossums are found at a variety of elevations. They may inhabit lowland rainforests at elevations as low as 60 m, or elfin forests on tepuis, or mesas, as high as 2,550 m. This species is known to inhabit the Venezuelan mountain, Cerro Marahuaca.

• Habitat Regions
• tropical tropical

• Terrestrial Biomes
• forest forest
• rainforest rainforest
• mountains mountains

Physical Description

Guianan white-eared opossums are member of the genus Didelphis . Until very recently, Guianan white-eared opossums were included in Didelphis albiventris , along with Andean white-eared opossums . In 2002, the white-eared opossum group was split into 3 separate species, white-eared opossums ( Didelphis albiventris ), Guianan white-eared opossums ( Didelphis imperfecta ) and Andean white-eared opossums ( Didelphis pernigra ). Due to this recent split, information regarding each of these new individual species is sparse.

There have been very few published accounts detailing the physical appearance of Guianan white-eared opossums. However, given that this species was grouped with Didelphis albiventris until very recently, it is likely that these species share many similarities. These opossums are relatively robust. The fur on their faces has a dusty-whitish hue, with a dark gray medial stripe. Guianan white-eared opossums typically have whitish ears and a pointed muzzle. Their prehensile tails are largely hairless and scaly, with the exception of fur at the base of the tail and a bit of sparse fur throughout. These species have a pronounced sagittal crest and the following dental formula: 5/4, 1/1, 3/3, 4/4. Females have a marsupium with 13 mammae.

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

Reproduction

There is no specific information regarding the mating systems of Guianan white-eared opossums. However, members of family Didelphidae are generally considered polygynous. Males compete for reproductive females, communicating with a series of clicking noises. Didelphids show neither courtship displays nor pair bonds.

• Mating System
• polygynous polygynous

There is little published information specifically regarding the reproductive behavior of Guianan white-eared opossums. However, there appears to be little behavioral variation in the studied members of their genus. These species typically have 2 breeding periods; breeding generally begins at the end of the dry season and offspring are born during the wet season. The gestation period for these species tends to be very short, about 12 to 14 days on average. The specific number of young produced by Guianan white-eared opossums is not known, however, their close relative Didelphis albiventris typically has 4 to 23 young. These offspring are extremely altricial; they are often about 15 mm long and weigh about 0.13 grams.

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

The parental investment of Guianan white-eared opossums has not been reported, however, research has been conducted on their close relative, white-eared opossums ( Didelphis albiventris ). Once the offspring of white-eared opossums are born, they must climb to the marsupium. Although a female may have many offspring within a litter, their marsupium only includes 13 mammae, as such, many of these altricial young will not survive. Young white-eared opossums remain within the pouch attached to the mammae for the first two months of their life, after which, they cling to their mothers back. They will stay with their mother for several more weeks; they are weaned at 3 to 4 months of age. White-eared opossums are sexually mature at around 9 months.

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

Lifespan/Longevity

The lifespan of Guianan white-eared opossums has not been reported, however, most didelphids have a very short lifespan. For instance, white-eared opossums typically do not survive beyond 20 months of age.

Behavior

Guianan white-eared opossums are solitary marsupials, although they may feed in similar areas with conspecifics, they do not interact. They are primarily terrestrial, but they are also adept climbers. These animals are nocturnal. During daylight hours Guianan white-eared opossums take shelter in abandoned termite nests, hallow trees or in the tree canopy, likewise, they may build leaf nests or burrow for refuge.

• Key Behaviors
• terricolous
• nocturnal nocturnal
• motile motile
• solitary solitary

Home Range

The home range size of Guianan white-eared opossums has not been reported.

Communication and Perception

The perception channels of Guianan white-eared opossums have not been reported, however, research has been conducted on other members of genus Didelphis . White-eared opossums primarily detect food items using their olfactory and auditory senses. In general, members of genus Didelphis also have very good eyesight. Likewise, members of this genus are equipped with long whiskers, which help them navigate at night. When these animals perceive a threat they typically bare their teeth, they can also run rather quickly when they are on the ground, their speed is impaired when they are climbing. In somewhat rare cases, when white-eared or Virginia opossums perceive an extreme threat, they may feign death.

• Communication Channels
• acoustic acoustic

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

Food Habits

There has been no published information regarding the food habits of Guianan white-eared opossums, however, there is a great deal of information regarding their close relative, white-eared opossums ( Didelphis albiventris ). White-eared opossums are omnivorous opportunistic feeders. They primarily feed on invertebrates, however, their diet changes based on food availability. Their diet components are generally as follows: 39% invertebrates, 28% vegetation including leaves, grasses and fibers, 17% birds, 12% fruits and seeds and 4% unknown. Among invertebrates, white-eared opossums typically feed on beetles , millipedes and dung beetles . Although both adult and young white-eared opossums have similar diets, adults are more likely to capture and consume vertebrate prey. When feeding, white-eared opossums sit in a semi-erect position, when consuming invertebrates and vertebrates, these animals typically eat the heads first.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• birds
• mammals
• reptiles
• insects

• Plant Foods
• leaves
• roots and tubers
• wood, bark, or stems
• seeds, grains, and nuts
• fruit

Predation

There are no specific reports regarding predation of Guianan white-eared opossums, however, white-eared opossums are predated upon by a variety of animals including maned wolves , felines , foxes , roadside hawks , barn owls , yellow anacondas and boa constrictors . Likewise, juvenile white-eared opossums may be prey for various adult snakes and great horned owls .

Ecosystem Roles

Although it has not been specifically reported for Guianan white-eared opossums, their close relative white-eared opossums are important seed dispersers, specifically for pioneer plants. Guianan white-eared opossums are commonly infested with the protozoans Trypanosoma cruzi and species of Leishmania . Other members of genus Didelphis are known to be reservoirs for numerous ecto- and endoparasites including nematodes , trematodes , ticks , mites and fleas .

Economic Importance for Humans: Positive

There are no known positive impacts of Guianan white-eared opossums on human populations.

Economic Importance for Humans: Negative

There are no known negative impacts of Guianan white-eared opossums on human populations.

Conservation Status

Guianan white-eared opossums are currently listed as a species of least concern according to the IUCN Red List of Threatened Species. These animals are believed to have a sizable and steady population.

Other Comments

Didelphis albiventris was split into 3 separate species in 2002, although there is some disagreement about the status of Didelphis imperfecta as a distinct species.

Additional Links

Encyclopedia of Life

Contributors

Leila Siciliano Martina (author), Texas State University.

References

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