Didelphis imperfectaGuianan white-eared opossum

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)

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)

  • 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)

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)

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)

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)

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)

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)

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)

  • 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)

Com­men­sal/Par­a­sitic Species
  • Try­panosoma cruzi
  • Leish­ma­nia

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)

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.

Glossary

Neotropical

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

World Map

acoustic

uses sound to communicate

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.

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.

carnivore

an animal that mainly eats meat

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.

female parental care

parental care is carried out by females

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynous

having more than one female as a mate at one time

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.

seasonal breeding

breeding is confined to a particular season

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.

visual

uses sight to communicate

viviparous

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

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.