Geographic Range
Wood-sprite opossums (
Gracilinanus dryas
) are found in northern South America in the Andes Mountains of western Venezuela
and northeastern Columbia. Their presence has been confirmed in Venezuela’s Cordillera
de Merida and Paramo de Tama, as well as Columbia’s Departmento Cudinamarca.
- Biogeographic Regions
- neotropical
Habitat
Wood-sprite opossums are an arboreal species found in wet montane forests. Their habitats
include pristine cloud forests, but they can also be found in secondary forests. These
animals live in a wide range of elevations, from 1,100 to 4,000 meters.
- Habitat Regions
- tropical
Physical Description
Wood-sprite opossums are small, pouchless marsupials with long, silky, dark brown
dorsal pelage and long brownish-gray ventral pelage. These animals are adapted for
an arboreal lifestyle, as shown by their long, unicolor tail. Their total body length
is about 250 mm, including a tail length of about 140 mm; in general, their tail-to-body
ratio is 1.2 to 1.7. Their hind feet are about 14 mm long. Wood-sprite opossums are
occasionally mistaken for their relative, northern gracile opossums (
Gracilinanus marica
); however, wood-sprite opossums have longer darker fur with striking, light colored
guard hairs, giving them a frosted appearance. Other members of genus
Gracilinanus
are sexually dimorphic, where males are larger than females; however, it is not known
whether this applies to wood-sprite opossums as well. Members of genus
Gracilinanus
may grow lifelong, these species are short-lived; however, the rare individuals that
survive multiple years tend to be noticeably larger. In general, the temperature and
metabolic rate of
didelphids
tends to be lower than similarly sized placental mammals.
- Other Physical Features
- endothermic
- bilateral symmetry
Reproduction
Didelphids
engage in a polygynous mating system. There is very little information specific to
wood-sprite opossums; however, the extreme competition among males for breeding females
may cause a massive amount of stress. Other members of genus
Gracilinanus
are considered partially semelparous because many of the males die shortly after
breeding. This trend is considered only partial because a few males do survive to
a second or even third breeding season.
- Mating System
- polygynous
There is very little information specifically regarding the reproductive behavior
of wood-sprite opossums. Much more research has been conducted on their close relative,
Brazilian gracile opossums
. It is not known whether these species share all reproductive traits, however, it
is not unlikely that these species share at least some reproductive traits. Brazilian
gracile opossums begin mating when they are about 1 year old. This species reproduces
seasonally; females are receptive during the end of the cool dry season, from August
to September. Several pregnant and lactating females have been captured in September
to December. Brazilian gracile opossums’ strategy of synchronous estrous means that
their young are born in October to December, during the first half of the warm wet
season when insect prey are most populous. This likely optimizes the female’s ability
to capture food while caring for young. Litters are composed of 6 to 14 individuals,
with an average of 11 offspring. Weaning begins at about 2 to 3 months of age, when
the young weigh about 8 to 10 grams.
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- viviparous
Genus
Gracilinanus
is composed of pouchless marsupials. Both attached and unattached young usually stay
near their mother; however, older offspring may stay behind in the nest while their
mother forages.
Brazilian gracile opossum
, a close relative of wood-sprite opossums, wean their offspring when they are about
2 to 3 months old, during the warm wet season.
- Parental Investment
- female parental care
Lifespan/Longevity
There is currently no information regarding the lifespan of wood-sprite opossums specifically,
however, other members of genus
Gracilinanus
typically live 1 to 2 years. Likewise, other members of this genus are considered
partially semelparous; most males do not survive to a second breeding season. Among
Brazilian gracile opossums
, a close relative of wood-sprite opossums, males invest so much in competing for
mates that they often show fur loss, poor body condition and are more likely to become
infested with parasites after the beginning of the breeding season. Although females
also have a short lifespan, they survive to a second year more frequently than males.
In general, the offspring from the preceding season replace the adults each year.
Behavior
Members of genus
Gracilinanus
are solitary and nocturnal; they typically only come together for breeding, they
may forage in a similar location, but do not interact. These animals are mostly arboreal,
but may forage on the ground. Other members of their genus are known to enter torpor
when the temperature is colder than 20°C.
Home Range
There is currently no information regarding the home range size of wood-sprite opossums.
However, their close relative,
Brazilian gracile opossums
have home range sizes of approximately 1,400 meters squared for males and 1,200 meters
squared for females.
Communication and Perception
There is very little information regarding the communication or perception of genus
Gracilinanus
. Members of this genus may produce a variety of sounds defensively or when they are
startled, these sounds include hissing, growling and screeching. It has been suggested
that arboreal marsupials are more vocal and have more adept vision than their non-arboreal
counterparts; however, no conclusive studies have been conducted.
Food Habits
Very little is known about the feeding habits of wood-sprite opossums. Other members
of genus
Gracilinanus
are insectivorous, consuming primarily
beetles
,
ants
and
wasps
. In addition, other members of the genus also eat fruits, especially during the dry
season and are important seed dispersers. Although these species are arboreal, most
forage on the ground.
- Primary Diet
- carnivore
- Animal Foods
- insects
- Plant Foods
- fruit
Predation
There is currently no information regarding the predation of wood-sprite opossum specifically,
however, general predators of genus
Gracilinanus
may include various
owls
,
snakes
and
lizards
. Similar species are predated upon by
white-tailed hawks
,
crab-eating foxes
,
oncillas
,
maned wolves
,
margays
and
jaguarundis
. Likewise, the remains of unidentified members of genus
Gracilinanus
have also been recorded in the scat of
ocelots
,
coatis
and
striped owls
.
Ecosystem Roles
Wood-sprite opossums are likely insectivores and seed dispersers. They are also known
to host a species of louse (
Cummingsia micheneri
). Other members of genus
Gracilinanus
are known to hosts of a variety of
nematodes
,
lice
and
botfly
larvae.
- lice ( Cummingsia micheneri )
Economic Importance for Humans: Positive
There are currently no known positive impacts of wood-sprite opossums on human populations.
Economic Importance for Humans: Negative
There are currently no known negative impacts of wood-sprite opossums on human populations.
Conservation Status
Wood-spite opossums are listed as near threatened according to the IUCN Red List of
Threatened Species. The primary threat to this species is habitat deforestation,
currently; populations are primarily restricted to high elevations.
Additional Links
Contributors
Leila Siciliano Martina (author), Texas State University.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- mountains
-
This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.
- polygynous
-
having more than one female as a mate at one time
- 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
- viviparous
-
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
- female parental care
-
parental care is carried out by females
- arboreal
-
Referring to an animal that lives in trees; tree-climbing.
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- solitary
-
lives alone
- visual
-
uses sight to communicate
- acoustic
-
uses sound to communicate
- visual
-
uses sight to communicate
- tactile
-
uses touch to communicate
- acoustic
-
uses sound to communicate
- chemical
-
uses smells or other chemicals to communicate
- carnivore
-
an animal that mainly eats meat
- insectivore
-
An animal that eats mainly insects or spiders.
- 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.
- 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.
References
Bianchi, R., S. Mendes. 2007. Ocelot ( Leopardus pardalis ) predation on primates in Caratinga Biological Station, southeast Brazil. American Journal of Primatology , 69: 1173-1178.
Bianchi, R., A. Rosa, A. Gatti, S. Mendes. 2011. Diet of margay, Leopardus wiedii , and jaguarundi, Puma yagouaroundi , ( Carnivora : Felidae ) in Atlantic rainforest, Brazil. Zoologia , 28:1: 127-132.
Bradshaw, S., W. Burggren, H. Heller, S. Ishii, H. Langer, G. Neuweiler, D. Randall. 1998. Hearing: The Brain and Auditory Communication in Marsupials . Berlin: Springer.
Cooper, C., P. Withers, A. Cruz-Neto. 2009. Metabolic, ventilatory, and hygric physiology of the gracile mouse opossum ( Gracilinanus agilis ). Physiological and Biochemical Zoology , 82:2: 153-162.
Creighton, G., A. Gardner. 2008. Genus Gracilinanus . Pp. 43-50 in Mammals of South America: Marsupials , Xenarthrans , Shrews , and Bats , Vol. 1. Chicago: University of Chicago.
Cruz, L., F. Fernandes, A. Linhares. 2009. Prevalence of larvae of the botfly Cuterebra simulans ( Diptera , Oestridae ) on Gracilinanus microtarsus ( Didelphimorphia , Didelphidae ) in southeastern cerrado from Brazil. Revista Brasileira de Entomologia , 53:2: 314-317.
Delciello, A., M. Vieira. 2009. Jumping ability in the arboreal locomotion of didelphid marsupials . Mastozoologia Neotropical , 16:2: 299-307.
Diaz, M., D. Flores, R. Barquez. 2002. A new species of gracile mouse opossum, genus Gracilinanus ( Didelphimorphia : Didelphidae ), from Argentina. Journal of Mammalogy , 83:3: 824-833.
Feijo, I., E. Torres, A. Maldonado Jr, R. Lanfredi. 2008. A new oxyurid genus and species from Gracilinanus agilis ( Marsupialia : Didelphidae ) in Brazil. Journal of Parasitology , 94:4: 847-851.
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 a Brazilian cerrado. Journal of Tropical Ecology , 26: 185-192.
Ferreira, G., E. Nakano-Oliveira, G. Genaro, A. Lacerda-Chaves. 2013. Diet of the coati Nasua nasua ( Carnivora : Procyonidae ) in an area of woodland inserted in an urban environment in Brazil. Revista Chilena de Historia Natural , 86: 95-102.
Granzinolli, M., J. Motta-Junior. 2006. Small mammal selection by the white-tailed hawk in southeastern Brazil. The Wilson Journal of Ornithology , 118:1: 91-98.
Hershkovitz, P. 1992. The South American gracile mouse opossums, genus Gracilinanus (Gardner and Creighton, 1989) ( Marmosidae , Marsupialia ): A taxonomic review with notes on general morphology and relationships. Field Zoology , 70: 1-56.
Martins, E., V. Bonato. 2004. On the diet of Gracilinanus microtarsus ( Marsupialia , Didelphidae ) in an Atlantic rainforest fragment in southeastern Brazil. Mammalian Biology , 69:1: 58-60.
Martins, E., V. Bonato, C. da Silva, S. dos Reis. 2006. Partial semelparity in the Neotropical didelphid marsupial Gracilinanus microtarsus . Journal of Mammalogy , 87:5: 915-920.
Martins, E., V. Bonato, C. da Silva, S. dos Reis. 2006. Seasonality in reproduction, age structure and density of the gracile mouse opossum Gracilinanus microtarsus ( Marsupialia : Didelphidae ) in a Brazilian cerrado. Journal of Tropical Ecology , 22:4: 461-468.
Motta-Junior, J., C. Alho, S. Belentani. 2004. Food habits of the striped owl Asio clamator in southeast Brazil. Journal of Raptor Research , 38: 777-784.
Perez-Hernandez, R., D. Lew, E. Gutierrez, J. Ventura. 2011. " Gracilinanus dryas " (On-line). IUCN Red List of Threatened Species. Accessed April 25, 2013 at www.iucnredlist.com .
Pires, M., E. Martins, M. Silva, S. dos Reis. 2010. Gracilinanus microtarsus . Mammalian Species , 42:1: 33-40.
Puttker, T., Y. Meyer-Lucht, S. Sommer. 2008. Effects of fragmentation on parasite burden ( nematodes ) of generalist and specialist small mammal species in secondary forest fragments of the coastal Atlantic forest, Brazil. Ecological Research , 23: 207-215.
Torres, E., A. Maldonado Jr, R. Lanfredi. 2009. Spirurids from Gracilinanus agilis ( Marsupialia : Didelphidae ) in Brazilian pantana wetlands with a new species of Physaloptera ( Nematoda : Spiruridae ). Veterinary Parasitology , 163: 87-92.
Torres, E., A. Maldonado Jr, R. Lanfredi. 2007. Pterygodermatites ( Paucipectines ) jagerskioldi ( Nematoda : Rictulariidae ) from Gracilinanus agilis and G. microtarsus ( Marsupialia : Didelphidae ) in Brazilian pantanal and Atlantic forest by light and scanning electron microscopy. Journal of Parasitology , 93:2: 274-279.
Voss, R., D. Fleck, S. Jansa. 2009. On the diagnostic characters, ecogeographic distribution, and phylogenetic relationships of Gracilinanus emiliae ( Didelphimorphia : Didelphidae : Thylamyini ). Mastozoologia Neotropical , 16:2: 433-443.
de Camargo, N., R. Cruz, J. Ribeiro, E. Vieira. 2011. Frugivory and potential seed dispersal by the marsupial Gracilinanus agilis ( Didelphidae : Didelphimorphia ) in areas of cerrado in central Brazil. Acta Botanica Brasilica , 25:3: 646-656.