Philander opossum

Geographic Range

Gray four-eyed opossums ( Philander opossum ) are Neotropical marsupials with a range that extends from northeastern Mexico in Tamaulipas, to southeastern Brazil. Within this range, they may be found from Brazil's Atlantic coast, westward into Peru and Argentina and throughout Central America in tropical lowlands and the Amazon and Parana basins.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Gray four-eyed opossums are found mainly in tropical forested areas such as tropical evergreen, secondary growth and gallery forests. However, they may be found in the southern portions of South America, where the habitat is more temperate. These opossums generally prefer damp areas near swamps and streams and usually reside in areas that receive more than 1,000 mm of rain per year. Gray four-eyed opossums may also be found in highly disturbed habitats near human structures or within agricultural areas such as orchards and sugar cane fields. These animals generally prefer lowland areas and are usually found below 1,000 m in elevation. They are primarily terrestrial; however, they are also proficient swimmers and are occasionally found on islands as a result.

• Terrestrial Biomes
• forest forest
• rainforest rainforest
• scrub forest scrub forest

• Wetlands
• swamp swamp

• Other Habitat Features
• agricultural agricultural

Physical Description

The common name, gray four-eyed opossum, is derived from their gray coat and the white spots located above each eye, which makes them appear to have four eyes. The coloration of their short, straight, soft hair is gray dorsally and off-white to yellow ventrally. Their dorsal pelage may vary slightly with their location, for instance, individuals in Mexico tend to have pale gray fur, in Central America they have dark gray fur and in Colombia they have dark brown to blackish fur. Their prehensile tail has grayish fur covering the first 50 to 60 mm from the base, the tip of their tail is naked and pale as it narrows towards the end. These animals have dark masks around their eyes, in contrast to the white coloration of their cheeks and chin. Their large, hairless ears are black along the edges. Their body length is 200 to 331 mm; with a tail length of 195 to 355 mm. Females are slightly smaller and have seven mammae within their pouch. Gray four-eyed opossums have a slender body and a large head. Their rostrum is fairly long and narrows at the tip. Their hind limbs are longer and more muscular than the forelimbs. In the wild, adults weigh between 200 and 674 g, however, captive individuals can weigh up to 1,500 g.

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

• Sexual Dimorphism
• male larger

Reproduction

There is no specific information regarding the mating systems of gray four-eyed 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

Most populations of gray four-eyed opossums reproduce seasonally, although some may breed throughout the year, with lower levels from June to August. During the rainy season, fruit is plentiful and more young may be cared for, while during the dry season, fruit is rare and fewer young are born. Reproduction only ceases entirely when the mother's nutritional requirements are not met. These animals produce 2 to 4 litters per year, however, success is low; many pouch young do not survive, especially during the dry months. Although the gestation period of gray four-eyed opossums has not been reported, a close relative, southern four-eyed opossums ( Philander frenatus ), have a 13 to 14 day gestation period. Litter sizes vary from 1 to 7 young, with an average of 4 to 5 young, each weighing about 9 g. Larger females, those over 445 grams, tend to have larger litters (about 5 per birth), while smaller females, those under 445 grams, have fewer young (about 3.8). Females become sexually mature at about 6 to 7 months, while males become sexually mature around 7 months.

• Key Reproductive Features
• semelparous semelparous
• seasonal breeding seasonal breeding
• year-round breeding year-round breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Young gray four-eyed opossums nurse from their mother’s pouch, which contains 7 mammae. These offspring are weaned when they are 68 to 75 days old, or when they weigh between 50 to 75 grams. After being weaned, young often stay in the nest for an additional 8 to 15 days, during this time, females may become aggressive toward the young.

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

Lifespan/Longevity

Gray four-eyed opossums may live up to 2.5 years in the wild. In captivity, these animals may live for up to 3.5 years.

Behavior

Gray four-eyed opossums are primarily nocturnal; however, some populations, such as those in Suriname, exhibit diurnal activity patterns as well. These animals generally construct nests from dried leaves in the lower branches of trees, 8 to 10 m from the ground; however, nests may also be found on the ground, in burrows, in fallen logs and in abandoned homes. Their nests are globular in shape and have a diameter of approximately 30 cm. Although they are proficient climbers and swimmers, much of their activity is terrestrial. Gray four-eyed opossums use their pronounced hind limbs for scampering and jumping along the forest floor. After being released from capture, they usually use a terrestrial escape route rather than climbing trees. Unlike other opossum species, gray four-eyed opossums are often described as swift, agile and aware.

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

Home Range

Although gray four-eyed opossums are solitary, these animals are generally not considered territorial, with overlapping home ranges and up to 150 individuals per km2. Their home ranges are not firmly established, animals may travel nomadically, particularly when food availability is low. In the Panama Canal Zone, their home range size was estimated at 3,400 m2.

Communication and Perception

Gray four-eyed opossums are not known as vocal animals, however, these animals do communicate with a series of clicks, chirps and hisses. Unlike many other opossum species, these animals do not ‘play possum’ when threatened, instead these animals will fiercely fight perceived threats. When they are in duress, they also make a series of threatening visual displays such as opening their mouths and hissing. Males also communicate with breeding females using sternal and abdominal scent glands.

• Communication Channels
• visual visual
• acoustic acoustic

• Other Communication Modes
• scent marks scent marks

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

Food Habits

Gray four-eyed opossums are omnivorous. About half of their diet consists of small animals such as insects, earthworms, birds, lizards, eggs, frogs, crustaceans, snails and small mammals, particularly spiny rats . The remainder of their diet includes leaves, bark, seeds, nuts, nectar and fruits such as papayas, bananas, sweet lemons and jobo plums. Their diet varies seasonally, during the wet season, they consume more plant matter because it is more widely available, during the dry season, they are much more insectivorous.

• Primary Diet
• omnivore omnivore

• Animal Foods
• birds
• mammals
• amphibians
• reptiles
• eggs
• insects
• mollusks
• terrestrial worms

• Plant Foods
• leaves
• roots and tubers
• seeds, grains, and nuts
• fruit
• nectar

Predation

Gray four-eyed opossums are preyed upon by a variety of mammals, owls and large reptiles such as Amazon tree boas , South American bushmasters , ocelots , jaguarundis , tayras , greater grisons , gray foxes and barn owls . Compared to other species of opossums, these animals are extremely fierce fighters, defending themselves violently as needed. Likewise, the white fur spots located above their eyes gives the appearance of always being awake and vigilant, which may detract some predators.

Ecosystem Roles

Gray four-eyed opossums are important dispersers for Cecropia seeds, particularly because they often deposit the seeds in high quality sites. Like most other opossum species, these animals carry a wide variety of internal and external parasites such as nematodes , trematodes , cestodes , fleas , mites , lice , ticks and chiggers .

Economic Importance for Humans: Positive

Gray four-eyed opossums help control insect and small vertebrate populations. In certain areas of Mexico, these animals are also hunted for food.

• Positive Impacts
• food food
• controls pest population

Economic Importance for Humans: Negative

Gray four-eyed opossums occasionally feed on corn fields and fruit crops, damaging farmer’s fields. Likewise, these animals are reservoirs for Trypanosoma cruzi .

• Negative Impacts
• injures humans
  • causes disease in humans causes disease in humans
• crop pest

Conservation Status

Currently, gray four-eyed opossums are considered a species of ‘least concern’ according to the IUCN Redlist of Threatened Species. Their conservation status was determined due to their large population size, large geographic range and tolerance to human disturbed environments.

Other Comments

Gray four-eyed opossums have a wide array of other common names such as tlacuache cuatro ojos, raton tlacuache gigante, zorrito de arbol, ooch, uc c’o, cayopolin, zorro de cuatro ojos, fo-ai awari, cucha gris de cuatro ojos, zorro, pericote, mucura-de-cuatro-olhos, carachupa, chucha mantequera, comadreja gris de cuatro ojos, Guaiki and mbicure. These animals are believed to have 4 subspecies, although it is under debate. The 4 currently recognized subspecies of gray four-eyed opossums include Pilander opossum canus , P.o. fuscogriseus , P.o. melanurus and P.o. opossum .

Additional Links

Encyclopedia of Life

Contributors

Leila Siciliano Martina (author, editor), Texas State University.

Michael Waters (author), University of Michigan-Ann Arbor, Phil Myers (editor), University of Michigan-Ann Arbor.

References

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Brito, D., A. Cuaron, F. Reid, L. Emmons. 2008. " Philander opossum " (On-line). IUCN Redlist of Threatened Species. Accessed September 10, 2013 at http://www.iucnredlist.org/details/40516/0 .

Castro-Arellano, I., H. Zarza, R. Medellin. 2000. Philander opossum . Mammalian Species , 638: 1-8.

Cerqueira, R. 1993. A Five-year Population Study of an Assemblance of Small Mammals in Southeastern Brazil. Mammalia , 57(4): 507-517.

Fernandes, F., L. Cruz, E. Martins, S. dos Reis. 2010. Growth and home range size of the gracile mouse opossums Gracilinanus microtarsus ( Marsupialia : Didelphidae ) in Brazilian cerrado. Journal of Tropical Ecology , 26:2: 185-192.

Fleck, D., J. Harder. 1995. Ecology of Marsupials in two Amazonian rain forests in northeastern Peru. Journal of Mammalogy , 76:3: 809-818.

Fonseca, S., R. Cerqueira. 1991. Water and Salt Balance in a South American Marsupial, the Gray Four-eyed Opossum (Philander opossum). Mammalia , 55(3): 421-432.

Gentile, R., R. Cerqueira. 1995. Movement Patterns of Five Species of Small Mammals in a Brazilian Restinga. Journal of Tropical Ecology , 11: 671-677.

Hershkovitz, P. 1997. Composition of the family Didelphidae Gray, 1821 ( Didelphoidea : Marsupialia ), with a review of the morphology and behavior of the included four-eyed pouched opossum of the genus Philander Tiedmann, 1808. Fieldiana: Zoology , 86: 1-103.

Hingst, E., P. Sergio D'Andrea, R. Santori, R. Cerqueira. 1998. Breeding of Philander frenata ( Didelphimorphia , Didelphidae ) in captivity. Laboratory Animals , 32: 434-438.

Julien-Laferriere, D., M. Atramentowicz. 1990. Feeding and Reproduction of Three Didelphid Marsupials in Two Neotropical Forests (French Guiana). Biotropica , 22(4): 404-415.

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

Patton, J., M. da Silva. 2007. Genus Philander Brisson, 1762. Pp. 27-35 in Mammals of South America: Marsupials, Xenarthrans, Shrews, and Bats , Vol. 1. Chicago: The University of Chicago Press.

Vieira, M. 1997. Body Size and Form in Two Neotropical Marsupials. Mammalia , 61(2): 245-254.