Animal Diversity Web

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. (Cerqueira and Tribe, 2008; Lew, et al., 2011)

• Biogeographic Regions
• neotropical
  • 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. (Cerqueira and Tribe, 2008; Lew, et al., 2011)

• Habitat Regions
• tropical

• Terrestrial Biomes
• forest
• rainforest
• mountains

• Range elevation

  60 to 2,550 m

  196.85 to ft

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. (Lemos and Cerqueira, 2002)

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. (Cerqueira and Tribe, 2008; Lemos and Cerqueira, 2002; Oliveira and San­tori, 1999; Smith, 2007; de Almeida, et al., 2008)

• Other Physical Features
• endothermic
• 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. (Fer­nan­des, et al., 2010; O'Con­nell, 2006)

• Mating System
• 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. (O'Con­nell, 2006; Rade­maker and Cerqueira, 2006; Smith, 2007; Ta­la­m­ondi and Dias, 1999)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• 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. (Cerqueira and Tribe, 2008; Rade­maker and Cerqueira, 2006; Smith, 2007)

• Parental Investment
• altricial
• 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. (Smith, 2007)

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. (Lew, et al., 2011; O'Con­nell, 2006; Rade­maker and Cerqueira, 2006)

• Key Behaviors
• terricolous
• nocturnal
• motile
• 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. (O'Con­nell, 2006; Oliveira and San­tori, 1999; Smith, 2007)

• Communication Channels
• acoustic

• Perception Channels
• visual
• tactile
• acoustic
• 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. (Alessio, et al., 2005; Cac­eres, 2002; Oliveira and San­tori, 1999; Oliveira-San­tos, et al., 2008; Smith, 2007; Ta­la­m­ondi and Dias, 1999)

• Primary Diet
• carnivore
  • 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. (Ja­como, et al., 2004; Oliveira and San­tori, 1999; Smith, 2007; Tomaz­zoni, et al., 2004)

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. (Cac­eres, 2002; Cerqueira and Tribe, 2008; For­nazari, et al., 2011; Quin­tal, et al., 2011; Smith, 2007)

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. (Lew, et al., 2011)

• IUCN Red List

  Lower Risk - Least Concern

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

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. (Lemos and Cerqueira, 2002; Lew, et al., 2011)

Con­trib­u­tors

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

Ref­er­ences

Alessio, F., A. Pontes, V. da Silva. 2005. Feed­ing by Didel­phis al­biven­tris on tree gum in the north­east­ern At­lantic forests of Brazil. Mas­to­zo­olo­gia Neotrop­i­cal, 12:1: 53-56.

Cac­eres, N. 2002. Food habits and seed dis­per­sal by the white-eared opos­sum Didel­phis al­biven­tris in south­ern Brazil. Stud­ies on Neotrop­i­cal Fauna and the En­vi­ron­ment, 37: 1-8.

Cerqueira, R., C. Tribe. 2008. Genus Didel­phis. Pp. 17-25 in A Gard­ner, ed. 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.

For­nazari, F., C. Teix­eira, R. da Silva, M. Leiva, S. de Almeido, H. Lan­goni. 2011. Preva­lence of an­ti­bod­ies against Tox­o­plasma gondii among Brazil­ian white-eared opos­sums (Didel­phis al­biven­tris). Vet­eri­nary Par­a­sitol­ogy, 179:1: 238-241.

Ja­como, A., L. Sil­veira, J. Di­niz-Filho. 2004. Niche sep­a­ra­tion be­tween the maned wolf (Chryso­cyon brachyu­rus), the crab-eat­ing fox (Du­si­cyon thous) and the hoary fox (Du­si­cyon ve­tu­lus) in cen­tral Brazil. Jour­nal of Zo­ol­ogy, 262: 99-106.

Lemos, B., R. Cerqueira. 2002. Mor­pho­log­i­cal dif­fer­en­ti­a­tion in the white-eared opos­sum group (Didel­phi­dae: Didel­phis). Jour­nal of Mam­mal­ogy, 83:2: 354-369.

Lew, D., R. Perez-Her­nan­dez, J. Ven­tura. 2011. "Didel­phis im­per­fecta" (On-line). IUCN Red List of Threat­ened Species. Ac­cessed May 02, 2013 at www.​iucnredlist.​org.

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.

Oliveira-San­tos, L., M. Tor­tato, M. Graipel. 2008. Ac­tiv­ity pat­tern of At­lantic for­est small ar­bo­real mam­mals as re­vealed by cam­era traps. Jour­nal of Trop­i­cal Ecol­ogy, 24: 563-567.

Oliveira, M., R. San­tori. 1999. Preda­tory be­hav­ior of the opos­sum Didel­phis al­biven­tris on the pitviper Both­rops jararaca. Stud­ies on Neotrop­i­cal Fauna and the En­vi­ron­ment, 34:2: 72-75.

Quin­tal, A., E. Ribeiro, F. Ro­drigues, F. Rocha, L. Floeter-Win­ter, C. Nunes. 2011. Leish­ma­nia spp. in Didel­phis al­biven­tris and Mi­coureus paraguayanus (Didel­phi­mor­phia: Didel­phi­dae) of Brazil. Vet­eri­nary Par­a­sitol­ogy, 176: 112-119.

Rade­maker, V., R. Cerqueira. 2006. Vari­a­tion in the lat­i­tu­di­nal re­pro­duc­tive pat­terns of the genus Didel­phis (Didel­phi­mor­phia: Didel­phi­dae). Aus­tral Ecol­ogy, 31:3: 337-342.

Smith, P. 2007. White-eared opos­sum Didel­phis al­biven­tris. Fauna Paraguay Hand­book of the Mam­mals of Paraguay, 1: 1-19. Ac­cessed May 07, 2013 at http:www.​faunaparaguay.​com/​mam1Didelphisalbiventris.​pdf.

Ta­la­m­ondi, S., M. Dias. 1999. Pop­u­la­tion and com­mu­nity ecol­ogy of small mam­mals in south­east­ern Brazil. Mam­malia, 63:2: 167-181.

Tomaz­zoni, A., E. Pedo, S. Hartz. 2004. Food habits of great horned owls (Bubo vir­gini­anus) in the breed­ing sea­son in Lami Bi­o­log­i­cal Re­serve, south­ern Brazil. Or­nitholo­gia Neotrop­i­cal, 15: 279-282.

de Almeida, A., C. Tor­quetti, S. Ta­la­m­oni. 2008. Use of space by Neotrop­i­cal mar­su­pialDidel­phis al­biven­tris (Didel­phi­mor­phia: Didel­phi­dae) in an urban for­est frag­ment. Re­vista Brasileira de Zo­olo­gia, 25:2: 214-219.