Caluromys philanderbare-tailed woolly opossum

Geographic Range

Bare-tailed woolly opossums, Caluromys philander, are found in the rainforests of South America. The northern end of their range is delimited by the Venezuelan Andes and extends east along the South American coast line to north-central Brazil. It then continues south in an east-heading arc that rejoins the Atlantic Costal-forest around 15-degrees south latitude. Their range follows the coast to about 28-degrees south latitude, which is their apparent southern limit. Bare-tailed woolly opossums are found in the interior rainforest to about 55-degrees west longitude including parts of the Bolivian lowland rainforest. They range up to 1,800 m in elevation in primary and secondary growth forests and are also found on the island of Trinidad. (Eisenberg and Redford, 1999; Eisenberg, 1989; Emmons and Feer, 1997)


Bare-tailed woolly opossums are highly arboreal. In studies of habitat use and partitioning they were rarely, if ever, found on the ground and seldom found in the understory. They are found in both primary- and secondary-growth evergreen tropical rainforests. They are known from damage to orchards and banana plantations. The preferred habitat of C. philander is not clear, and varies dependent upon season, geographic locality, food availability, and reproductive status. These animals show a preference for denser canopy within their habitat, likely for concealment from predators. They nest in tree hollows lined with leaves or in leaf-nests in the canopy. (Eisenberg and Redford, 1999; Eisenberg, 1989; Grelle, 2003; Husson, 1978; Julien-Laferriere and Atramentowicz, 1990; Julien-Laferriere, 1999; Leite, et al., 1996)

  • Range elevation
    1,800 (high) m

Physical Description

Bare-tailed woolly opossums are medium-sized new-world arboreal opossums. Their weight ranges from 140 g to 390 g, with females being smaller than males. The average caloric intake for a 300 g individual is approximately 300 kJ/day. The body length, head to base of tail, is 160 mm to 279 mm and is always less than the length of the tail. The tail ranges from 250 mm to 405 mm in length. Outside ear length is 30 mm to 40 mm and hind foot length is 33 mm to 40 mm. The dental formula is I 5/4, C 1/1, P 3/3, M 4/4. The species has a distinctive post orbital process that can help distinguish it from other Neotropical marsupials. (Atramentowicz, 1995; Eisenberg and Redford, 1999; Eisenberg, 1989; Emmons and Feer, 1997; Husson, 1978; Schmitt and Lemelin, 2002)

The fur is generally soft and thick, with individuals in the lowlands having shorter coats than those in the uplands. The pelt has also been referred to as woolly, but all members of the genus Caluromys have a “woolly” pelt. The back is a reddish-brown with gray gradating in along the flanks. The belly is a yellowish-orange to gray color. The head is gray with three distinct dark-brown strips; one runs down the bridge of the muzzle from crown to nose and the other two extend from dark-brown eye-rings to the nose. The tail is furred for the first tenth to quarter of its length with a sharp demarcation between the furred and bare portions. The furless portion of the tail is cream to dark-gray or dark-brown in color, and is usually mottled with brown or white spots. Like many other Didelphidae the tail is also prehensile and helps with climbing, balancing, and grasping. (Atramentowicz, 1995; Eisenberg and Redford, 1999; Eisenberg, 1989; Emmons and Feer, 1997; Husson, 1978; Schmitt and Lemelin, 2002)

The eye-shine of bare-tailed woolly opossums is yellow and makes the eyes appear small. Females have a vestigial pouch, termed a marsupium, which is only present when they are carrying young. They also have seven mammae concealed by the marsupium. (Atramentowicz, 1995; Eisenberg and Redford, 1999; Eisenberg, 1989; Husson, 1978; Schmitt and Lemelin, 2002)

  • Sexual Dimorphism
  • male larger
  • Range mass
    140 to 390 g
    4.93 to 13.74 oz
  • Average mass
    250 g
    8.81 oz
  • Range length
    410 to 684 mm
    16.14 to 26.93 in


The mating system of C. philander is little understood. Individuals are solitary except when males are courting females. Courtship may simply occur through chance meetings as the territories of many individual overlap. (Eisenberg and Redford, 1999; Eisenberg, 1989; Julien-Laferriere, 1995)

Bare-tailed woolly opossums have up to 3 litters per year, but this is dependent upon resource availability. In one study, the breeding season was defined as beginning in September when there was an increase in the number of pregnant females concurrent with an increase in resource availability.

The average number of young varies greatly throughout the year dependent upon resource availability, habitat type, local conditions, as well as female age and mass. A female can have up to 7 young at once, but the average is 4.17 in the wild. There does not appear to be any additional cost to the female for large litters. It seems that the costs are borne by the young who are weaned at a smaller size in large litters than in small litters, indicating that regardless of litter size, female investment in any given litter is approximately constant.

Bare-tailed woolly opossums have a relatively short gestation period followed by an extended period of parental care. The gestation lasts only 24 days, and the young are born weighing less than 200 mg, with a length of 10 mm. This short time in utero is made up for by an extended period (up to 120 days) of pouch time. This period has two sub-periods, day 1 to 92, when the young are attached to the teat, and day 93 to weaning, when the young make short external excursions. The time in the pouch is followed by another 30 to 45 days in the mother’s nest. After this period the young leave the protection of the mother. The importance of leaving the maternal nest is demonstrated by the behavior of young in captivity. When young have not been removed after this period, they have been observed to cannibalize their mother.

Females reach sexual maturity around 270 days of age. The age of sexual maturity for males is not known. Little is known about the estrous cycle, but direct contact with males seems to induce fertility. This is hypothesized to result from pheromonal or behavioral cues from the male. (Atramentowicz, 1992; Atramentowicz, 1995; Guillemin, et al., 2000; Julien-Laferriere and Atramentowicz, 1990; Julien-Laferriere, 1995; Perret and Benmbarek, 1991)

  • Breeding interval
    In theory, a female could produce a new litter every 200 days.
  • Breeding season
    The breeding of this species is aseasonal, but peaks matching resource availability
  • Range number of offspring
    1 to 7
  • Average number of offspring
  • Average number of offspring
  • Average gestation period
    24 days
  • Average gestation period
    24 days
  • Range weaning age
    103 to 120 days
  • Range time to independence
    150 to 165 days
  • Average age at sexual or reproductive maturity (female)
    270 days
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    304 days

In bare-tailed woolly opossums, care for the young is the singular responsibility of the female. After the short gestation period, the young are born quite undeveloped and altricial, requiring as much as 120 days in the marsupium to complete their development. Over the 144 to 159 days of care the mother protects and feeds them without any other assistance. Little is known about post dependence interactions. (Eisenberg and Redford, 1999; Eisenberg, 1989)

  • Parental Investment
  • no parental involvement
  • altricial
  • female parental care
  • pre-fertilization
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female


Little is known about the lifespan of bare-tailed woolly opossums. Captive animals have lived for up to five years and animals of a minimum age of 31 to 41 months were captured in a mark-recapture study. (Gewalt, 1990; Julien-Laferriere and Atramentowicz, 1990)


Bare-tailed woolly opossums are an arboreal species; they are rarely found in the understory and never on the ground. They prefer a dense upper-canopy for protection and nest in tree hollows or leaf nests within the canopy. They are nocturnal and tend to be more active for longer periods during the new moon apropos to the full moon. Nightly activity consists of foraging over their territory. Foraging duration lasts an average of 72.2 minutes followed by a period of rest and it is uncommon for more than two trees to be visited per night. C. philander has not been observed entering daily or seasonal torpor.

C. philander is not a very territorial species. Territories are loosely defended; male territories overlap and contain the territories of several females. Territory expanse depends on the sex and size of the individual and the level of resource availability. Depending on resource availability, population density ranges from 51 individuals per square-kilometer in primary forest to 151 individuals per square-kilometer in secondary forests. Encounters between individuals are agonistic and in lab studies a discreet social hierarchy was found to exist based on individual size with larger individuals being dominant. This limited the amount of overtly aggressive behavior during encounters, likely as a means of preventing unnecessary injury. Bare-tailed woolly opossums, however, are not docile and if attached or trapped they will bite. (Eisenberg and Redford, 1999; Eisenberg, 1989; Grelle, 2003; Julien Laferriere, 1997; Julien-Laferriere and Atramentowicz, 1990; Julien-Laferriere, 1995; Julien-Laferriere, 1999; Leite, et al., 1996)

  • Range territory size
    .013 to .089 km^2
  • Average territory size
    .031 km^2

Home Range

The home range of a bare-tailed woolly opossum ranges from 1.3 hectares to 8.9 hectares with an average of 3.1 hectares for adults. This area may not be held exclusively by one individual and may overlap with the home ranges of several others. These areas may also be very liquid and transient. Juveniles exhibit a very high degree of dispersal from their natal territory. Adults exhibit similar characteristics with an average territory residency time of 7.7 months and a maximum residency of 21 months. Home range extent is dependent upon the age and sex of the individual; adults have larger home ranges than juveniles and females have larger home ranges than males. Home ranges have several core areas within them. The average number of core areas per territory is 4.4 and these seem to be based on food trees and not den sites. (Eisenberg and Redford, 1999; Eisenberg, 1989; Julien-Laferriere, 1995)

Communication and Perception

Bare-tailed woolly opossums are generally quiet animals; they move as silently as possible through the tree branches. Most of their communication occurs during intraspecific encounters. In these cases they hiss in a manner similar to other opossums unless it is an encounter between a courting male and receptive female. They are also known to make clicking sounds and in the suckling young this is believed to strengthen the bond between mother and young. When taken by a predator, bare-tailed woolly opossums are known to give a distress scream. (Eisenberg and Redford, 1999; Eisenberg, 1989; Emmons and Feer, 1997)

Given the feeding habits of bare-tailed woolly opossums, it is likely that they have a developed sense of smell to help them find ripe fruit and flowers. The eyes and ears are also large and likely help them navigate the night-time forest and capture insects. These attributes make it likely that the animals also use some sorts of visual communication (such as body postures) and chemical communication (such as pheromones hypothesized to be important in inducing ovulation). Tactile communication is undoubtedly important during mating, as well as between a mother and her young.

Food Habits

C. philander is omnivorous; the diet is composed of approximately 25 percent arthropods and 75 percent fruit, nectar, and tree gum. Because of the seasonal availability of food, the diet varies greatly throughout the year. During the wet-season, fruits and arthropods are much more abundant, whereas during drier periods, flowers and gums are much more common. Because of this, bare-tailed woolly opossums have a long colon and well developed caecum to help with the processing of fibrous material. They eat ripe fruit, and are able to determine ripeness by non-visual queues as they feed on brightly-colored as well as cryptically-colored fruit. (Julien-Laferriere and Atramentowicz, 1990; Julien-Laferriere, 1999; Leite, et al., 1996; Linares, 1998)

Beetles and butterflies are the primary arthropods they prey upon, but other insects are taken. Two tree-species make up their primary diet; these are Eperua falcate, for nectar, and Symphonia globulifera, for fruit and nectar. Sixty-four percent of the fruit intake for bare-tailed woolly opossums in French Guiana came from five tree-species: Symphonia globulifera, Tapirira guianensis, Dacryodes nitren, Licania robusta and Humiriastrum subcrenatum. Eighty-three percent of the nectar diet came from three tree-species: Eperua falcate, Symphonia globulifera, and Norantea guianensis. (Julien-Laferriere and Atramentowicz, 1990; Julien-Laferriere, 1999; Leite, et al., 1996; Linares, 1998)

  • Animal Foods
  • mammals
  • insects
  • Plant Foods
  • fruit
  • nectar
  • sap or other plant fluids


Given the moderately small size of bare-tailed woolly opossums, they are a prey item for many species. Arboreal nocturnal snakes and cats, such as Leopardus wiedii, are suggested as predators. Additionally, raptors, such as Morphnus guianensis, and the Strigidae are implicated. (Husson, 1978; Julien Laferriere, 1997)

Ecosystem Roles

The role of bare-tailed woolly opossums in tropical forests is not specifically known. They likely play host to many parasites. They also likely aid some small-seeded fruit-bearing tree-species in the dispersal of seeds and in the pollination of other species. They certainly are important for forest-floor species, as they knock down fruit from the overstory. One final role is that of a tasty protein morsel for many species of arboreal predators. (Perret and Benmbarek, 1991; Schmitt and Lemelin, 2002)

  • Ecosystem Impact
  • disperses seeds
  • pollinates
Species Used as Host
  • Unknown
Mutualist Species
  • Unknown
Commensal/Parasitic Species
  • Unknown

Economic Importance for Humans: Positive

The only obvious economic benefit from bare-tailed woolly opossums has been in research. They have been used to study primitive gait patterns and for a limited amount of evolutionary investigation. (Perret and Benmbarek, 1991; Schmitt and Lemelin, 2002)

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

There is some evidence that bare-tailed woolly opossums have done damage in banana plantations, but given their size and population density, this is very limited in scope. (Husson, 1978)

  • Negative Impacts
  • crop pest

Conservation Status

Bare-tailed woolly opossums are not listed as a species of conservation concern. They are small and able to adapt to various types of neotropical forests, are not involved in trade, or considered a pest to humans. However, as deforestation continues in neotropical regions, it is likely that this species will face growing pressure.

Other Comments

C. philander has a wide geographic range and is know by many common names. These are: bare-tailed woolly opossum (English), yellow opossum (German), Awari (Surinamese), philander or Wollige opossum (Dutch), comadreja lunuda cola desnuda or comadreja rabuda (Venezuelan), Mucura-chichica (Brazilian), kotori o mahihimi (Yanomami). Historically, the species was called both Philander philander and Didelphis philander; these names are no longer commonly used nor are they appropriate. (Emmons and Feer, 1997; Gewalt, 1990; Husson, 1978; Linares, 1998)


Nancy Shefferly (editor), Animal Diversity Web.

Andrew Strassman (author), University of Michigan-Ann Arbor, Phil Myers (editor, instructor), Museum of Zoology, University of Michigan-Ann Arbor.



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.


uses smells or other chemicals to communicate

dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates


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


union of egg and spermatozoan

induced ovulation

ovulation is stimulated by the act of copulation (does not occur spontaneously)


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.


active during the night


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


chemicals released into air or water that are detected by and responded to by other animals of the same species


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.


remains in the same area


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


lives alone


uses touch to communicate


Living on the ground.


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


movements of a hard surface that are produced by animals as signals to others


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


2004. "Convention on International Trade in Endangered Species of Wild Fauna and Flora" (On-line). CITES - Listed Species Database. Accessed February 12, 2004 at

2004. "U.S. Fish and Wildlife Service" (On-line). Species Information: Threatened and Endangered Animals and Plants. Accessed February 12, 2004 at

Atramentowicz, M. 1995. Growth of Pouch Young in the Bare-tailed Woolly Opossum, Caluromys philander . Journal of Mammalogy, 76 (4): 1213 - 1219.

Atramentowicz, M. 1992. Optimal Litter Size - Does it cost more to raise a large litter in Caluromys philander. Canadian Journal of Zoology, 70 (8): 1511 - 1515.

Eisenberg, J. 1989. Mammals of the Neotropics: The Northern Neotropics, Volume 1, pp 24 - 25. Chicago: The University of Chicago Press.

Eisenberg, J., K. Redford. 1999. Mammals of the Neotropics: The Central Neotropics, Volume 3, pp 78 - 80. Chicago: The University of Chicago Press.

Emmons, L., F. Feer. 1997. Neotropical Rainforest Mammals: A Feild Guide, Second Edition, pp 12 - 13. Chicago: The University of Chicage Press.

Gewalt, W. 1990. Other Opossums. Pp. 239 - 240 in B Grzimek, ed. Grzimek's Encyclopedia of Mammals, Vol. 1, Second Edition. St. Louis: McGraw Hill Publishing.

Grelle, C. 2003. Forest structure and vertical stratification of small mammals in a secondary Atlantic forest, southeastern Brazil. Studies on Neotropical Fauna and Environment, 32 (2): 81 - 85.

Guillemin, M., M. Atramentowicz, P. Charles-Dominique. 2000. Dominance relationships in captive male bare-tailed woolly opossum (Caluromys philander, Marsupialia : Didelphidae). Revue d'Ecologie - La Terre et La Vie, 55(4): 337 - 349.

Husson, A. 1978. The Mammals of Suriname, pp 8 - 11. Leiden, The Netherlands: E.J. Brill.

Julien Laferriere, D. 1997. The influence of moonlight on activity of woolly opossums (Caluromys philander). Journal of Mammalogy, 78 (1): 251 - 255.

Julien-Laferriere, D. 1999. Foraging strategies and food partitioning in the neotropical frugivorous mammals Caluromys philander and Potos flavus . Journal of Zoology, 247: 71 - 80.

Julien-Laferriere, D. 1995. Use of Space by the Woolly Opossum, Caluromys philander (Marsupialia, Didelphidae) in French-Guiana. Canadian Journal of Zoology, 73 (7): 1280 - 1289.

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

Leite, Y., L. Costa, J. Stallings. 1996. Diet and vertical space use of three sympatric opossums in a Brazilian Atlantic forest reserve. Journal of Tropical Ecology, 12: 435 - 440.

Linares, O. 1998. Mamiferos de Venezuela, pp 26 - 28. Caracas: Sociedad Conservacionista Audubon de Venezuela.

New World Marsupial Specialist Group 1996, 2004. "Caluromys philander" (On-line). IUCN Red List of Threatened Species. Accessed February 12, 2004 at

Perret, M., S. Benmbarek. 1991. Male Influence on Estrous Cycles in Female Woolly Opossums (Clauromys philander). Journal of Reproduction and Fertility, 91 (2): 557 - 566.

Schmitt, D., P. Lemelin. 2002. Origins of Primate Locomotion: Gait Mechanics of the Woolly Opossum. American Journal of Physical Anthropology, 118: 231 - 238.