Caluromys lanatuswestern woolly opossum

Geographic Range

Caluromys lanatus, the western or brown eared woolly opossum, is a South American opossum species. Its distribution ranges east of the Corillera Central and Andes mountain ranges in Colombia, northwestern and southern Venezuela, eastern Ecuador, eastern Peru, northern Bolivia, eastern Paraguay, northern Argentina, and western Brazil. (Allen, 2007; Emmons and Feer, 1997)

There are six recognized subspecies of C. lanatus, each distinguished by its range. Caluromys lanatus cicur is found in northeastern Colombia and northwestern Venezuela. Caluromys lanatus lanatus is found in Paraguay, provincia Misiones in Argentina, and the state of Rio Grande do Sul in southern Brazil. Caluromys lanatus nattereri is found in the Mato Grosso and Mato Grosso do Sul states of southwestern Brazil and adjacent Bolivia. Caluromys lanatus ochropus is found in southern Venezuela and western Brazil. Caluromys lanatus ornatus is found in southern Colombia and east of the Andes in Ecuador, Peru, and Bolivia. Caluromys lanatus vitalinus is found in southeastern Brazil. (Allen, 2007)


Caluromys lanatus resides in lowland humid forests between 200 and 1300 m in altitude, more commonly below 500 m. It is mostly found near streams or other moist areas, but also occupies drier areas. Although it prefers dense, primary, midstory and canopy forests with vines and epiphytes, it can also be found in open forests, mature and secondary evergreen rainforest, forest that has been disturbed, gallery forest, and even gardens and plantations. Caluromys lanatus uses the middle and upper strata of trees in these environments, so it is typically caught in traps 5-15 m above ground. In Brazil, C. lanatus can be found in both terra firme and várzea forests. (Allen, 2007; Emmons and Feer, 1997; Handley Jr., 1976; Lambert, et al., 2005; Patton, et al., 2000; Tirira, 2007)

  • Range elevation
    200 to 1300 m
    656.17 to 4265.09 ft

Physical Description

Caluromys lanatus is a medium-sized, slender opossum with a broad head and pointed snout. Its head and body length is 201-319 mm, tail length is 330-435 mm, and weight is 290-410 g. It has long, dense, woolly hair that is reddish-brown to pale brown on the dorsum and sides, and yellowish white on the venter, sometimes with gray in the center. The reddish color is darker on the shoulders, forearms, and hind legs. The face of C. lanatus is gray with a dark stripe down the center, reddish brown eye rings around large brown eyes, and large, naked, brownish ears. The feet are reddish brown to dark gray in color. Its tail is prehensile, with thick fur up to 50% from the base on the dorsum and up to 20% on the venter. The remainder of the tail is naked, with a portion of the skin spotted with brown spots. Females develop pouches only when carrying young. (Emmons and Feer, 1997; Linares, 1998; Tirira, 2007)

Some subspecies of Caluromys lanatus differ in their physical appearance. Caluromys lanatus cicur has a grayish-brown dorsum, gray sides, and can have a completely gray venter. Caluromys lanatus lanatus has pale brown fur and lacks any pigmented spots on the tail. Caluromys lanatus ochropus has a distinct red-brown dorsum, and is larger than nearby C. l. lanatus. (Cáceres and Carmignotto, 2006; Emmons and Feer, 1997)

The range of Caluromys lanatus overlaps with several species similar in appearance. However, Caluromysiops irrupta has black shoulders and a tail furred all the way to the tip, Glironia venusta has two dark stripes on the head instead of one and a tail furred all the way to the tip, species in the genus Micoureus have no dark stripe on their heads and tails furred only by the base, and Caluromys philander has a tail only furred near the base. (Emmons and Feer, 1997)

  • Range mass
    290 to 410 g
    10.22 to 14.45 oz
  • Range length
    201 to 319 mm
    7.91 to 12.56 in


Caluromys lanatus most likely breeds year-round, as pouched young and postlactating females have been caught throughout the year, and females cycle throughout the year. Litter sizes are small, with 1-2 young in the Amazon Basin and 3-4 young in southern portions of the range. They reach sexual maturity at the age of 7-8 months. The length of estrus for females is 20-31 days, and females can have up to three litters in one year. The average body mass of young averaged 3.5 g in a seasonal forest in Brazil. (Bucher and Fritz, 1977; Cáceres and Carmignotto, 2006; Linares, 1998; Patton, et al., 2000)

Little else seems to be known about reproduction in this species, but other opossums with known reproductive behavior give birth to highly altricial young that are nursed by the female for at least several weeks and probably remain at least partially dependent on maternal care of some sort for at least another month.

  • Breeding interval
    Caluromys lanatus can have up to three litters in one year.
  • Breeding season
    Caluromys lanatus breeds year-round.
  • Range number of offspring
    1 to 4

As far as known all female opossums nurse newborn young, groom them, and presumably protect them from predators for at least several weeks postpartum. Paternal care has not been reported for any opossum species.

  • Parental Investment
  • altricial
  • female parental care
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female


Caluromys lanatus is a nocturnal, arboreal species that is solitary. It spends the daylight hours in hollow trees, where it may also build its nest. It moves slowly and quietly during the night, slowly approaching and capturing insects with its hands. It is also a curious species that will approach human encampments, perhaps to prey upon the insects that are attracted to lights. It will react aggressively when caught and handled. (Bucher and Fritz, 1977; Emmons and Feer, 1997; Linares, 1998; Tirira, 2007)

Home Range

At one central Amazon site in Brazil, the density of C. lanatus was 13.3 individuals/km^2. (Peres, 1999)

Communication and Perception

Caluromys lanatus makes few sounds, but will make clicking sounds during mating and hissing sounds when threatened. The eyes, ears, nasal turbinates (thin bones that support olfactory epithelium), and tactile hairs are well developed in this species (as in other opossums), so vision, hearing, and touch are probably important senses. Which of these senses is actually used for communication is unknown. (Linares, 1998; Tirira, 2007)

Food Habits

Caluromys lanatus is an omnivore. It primarily eats fruits (80-85% of diet), but also consumes soft vegetables, insects, other invertebrates, small vertebrates (15-20% of diet). It will also drink flower nectar in the dry season and the gum and sap from the bark of certain trees. One study performed by Casella and Cáceras (2006) in southern Brazil found that all trapped C. lanatus individuals ate fruits, including those of the species Cecropia pachystachia, Cyphomandra sp., Ficus luschnatiana, Piper sp., and species in the family Solanaceae. All individuals also ate invertebrates in the orders Coleoptera and Hymenoptera. In addition, 40% of individuals consumed birds, 60% consumed mammals, and 40% consumed unidentified plant parts. (Casella and Cáceras, 2006; Emmons and Feer, 1997; Linares, 1998; Tirira, 2007)

  • Animal Foods
  • birds
  • mammals
  • Plant Foods
  • fruit
  • nectar


Little is known about what preys upon C. lanatus, but the closely related Caluromys derbianus and Caluromys philander have been found in the stomach contents of the pitvipers Bothrops asper and Bothrops jararaca. Besides snakes, other predators likely include owls and wild felids. (Voss, 2013)

Ecosystem Roles

Since Caluromys lanatus is a mobile opossum that consumes flower nectar in the dry season, it is a potential pollinator for these flowering species. Such plant species include Quararibea cordata and Pseudobombax tomentosum. Caluromys lanatus individuals have also been found to carry Trapanosoma cruzi and Ablyomma nymphs in Brazil, Colombia, and Peru. Additional probable ectoparasites include species of Arachnida (Acari: mites) and Insecta (Siphonaptera: fleas). Probable endoparasites include species of Acanthocephala (spiny-headed worms), Cestoda (tapeworms),Digenea (flukes), and Nematoda (roundworms). (Cáceres and Carmignotto, 2006; Gribel, 1988; Janson, et al., 1981)

Commensal/Parasitic Species
  • Trapanosoma cruzi
  • Ablyomma

Economic Importance for Humans: Positive

Caluromys lanatus was formerly hunted for its fur, but the fur is no longer in demand, so hunting by humans has most likely been reduced. The Yekuana and Yanomami people in the Amazon will occasionally trap C. lanatus individuals as pets for children. (Emmons and Feer, 1997; Linares, 1998)

  • Positive Impacts
  • body parts are source of valuable material

Economic Importance for Humans: Negative

Species in the genus Caluromys have been known to eat fruit grown on fruit plantations, which may be perceived as a negative economic impact for fruit farmers. (Fleck and Harder, 1995)

Conservation Status

Caluromys lanatus is considered a species of least concern by IUCN Red List because it has a wide distribution, a presumably large population, and occurs in protected areas throughout its range. Deforestation may be a threat for some populations, as it is an arboreal species. (Costa, et al., 2008; Linares, 1998)


Rachel Cable (author), Animal Diversity Web Staff.



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

World Map


uses sound to communicate


living in landscapes dominated by human agriculture.


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.


Referring to an animal that lives in trees; tree-climbing.

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.


an animal that mainly eats meat


uses smells or other chemicals to communicate


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


an animal that mainly eats fruit


An animal that eats mainly plants or parts of plants.


An animal that eats mainly insects or spiders.


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).


having the capacity to move from one place to another.

native range

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


an animal that mainly eats nectar from flowers


active during the night


an animal that mainly eats all kinds of things, including plants and animals


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.


reproduction that includes combining the genetic contribution of two individuals, a male and a female


lives alone


uses touch to communicate


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


uses sight to communicate


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

year-round breeding

breeding takes place throughout the year


Allen, J. 2007. Genus Caluromys. Pp. 3-11 in A Gardner, ed. Mammals of South America. Chicago: The University of Chicago Press.

Bucher, J., H. Fritz. 1977. Behavior and maintenance of the woolly opossum (Caluromys) in captivity. Laboratory Animal Science, 27/6: 1007-1012.

Casella, J., N. Cáceras. 2006. Diet of four small mammal species from Atlantic forest patches in South Brazil. Neotropical Biology and Conservation, 1: 5-11.

Costa, L., D. Astua de Moraes, D. Brito, P. Soriano, D. Lew, C. Delgado. 2008. "Caluromys lanatus" (On-line). IUCN 2012: The IUCN Red List of Threatened Species. Accessed April 02, 2013 at

Cáceres, N., A. Carmignotto. 2006. Caluromys lanatus. Mammalian Species, 803: 1-6.

Emmons, L., F. Feer. 1997. Neotropical Rainforest Mammals: A Field Guide, Second Edition. Chicago: The University of Chicago Press.

Fleck, D., J. Harder. 1995. Ecology of Marsupials in Two Amazonian Rain Forests in Northeastern Peru. Journal of Mammalogy, 75/3: 809-818.

Gribel, R. 1988. Visits of Caluromys lanatus (Didelphidae) to Flowers of Pseudobombax tomentosum (Bombacaceae): A Probable Case of Pollination by Marsupials in Central Brazil. Biotropica, 20/4: 344-347.

Handley Jr., C. 1976. Mammals of the Smithsonian Venezuelan Project. Brigham Young University Science Bulletin, 20/5: 1-89.

Janson, C., J. Terborgh, L. Emmons. 1981. Non-Flying Mammals as Pollinating Agents in the Amazonian Forest. Biotropica Supplement: Reproductive Botany, 13/2: 1-6.

Lambert, T., J. Malcolm, B. Zimmerman. 2005. Variation in Small Mammal Species Richness by Trap Height and Trap Type in Southeastern Amazonia. Journal of Mammalogy, 86/5: 982-990.

Linares, O. 1998. Mamíferos de Venezuela. Caracas: Sociedad Conservacionista Audubon de Venezuela.

Patton, J., M. da Silva, J. Malcolm. 2000. Mammals of the Rio Juruá and the evolutionary and ecological diversification of Amazonia. Bulletin of the American Museum of Natural History, 244: 1-306.

Peres, C. 1999. The structure of nonvolant mammal com- munities in different Amazonian forest types. Pp. 564-581 in J Eisenberg, K Redford, eds. Mammals of the Neotropics, the central Neotropics: Ecuador, Peru, Bolivia and Brazil. Illinois: University of Chicago Press.

Tirira, D. 2007. Guía de campo de los mamíferos del Ecuador. Quito, Ecuador: Muciélago Blanco.

Voss, R. 2013. Opossums (Mammalia: Didelphidae) in the diets of Neotropical pitvipers (Serpentes: Crotalinae): Evidence for alternative coevolutionary outcomes?. Toxicon, 66: 1-6.