Philander andersoni

Geographic Range

The range of Philander andersoni , Anderson's four-eyed opossum, extends from southcentral Venezuela and the northwestern Amazon basin in Brazil, through southern Colombia, to the eastern foothills of the Andes in Ecuador and northern Peru.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Philander andersoni occupies primary and secondary lowland forests within its range, as well as gallery forests along wetland and riparian areas. Much like other species in the genus Philander , P. andersoni is mostly terrestrial, but has been known to climb into trees. Individuals of P. andersoni prefer dense vegetation, but can be found, though not frequently, in areas of high human disturbance, such as agricultural lands. In Ecuador, P. andersoni can be found between 200 and 1600 m above sea level, but it is most often found below 600 m of elevation.

• Habitat Regions
• tropical tropical

• Terrestrial Biomes
• forest forest

Physical Description

Like all species of the genus Philander , this species has lighter spots above the eyes, giving the appearance of “four eyes.” It also has a slim body and a relatively large head with a long, conical-shaped muzzle. All species in this genus also have slim, partially furred prehensile tails that are equal to or longer than the body length. Individuals have opposable pollex on the forefeet and opposable hallux on the hindfeet. Females have fully developed pouches.

Philander andersoni is a large opossum with body length 250-350 mm, tail length 250-350 mm, and mass 240-600 g. Males are slightly larger than females. Philander andersoni has short gray hair on its sides and a band of short black hair approximately 3-4 cm wide that runs dorsally from the head to the base of the tail. This dorsal band aids in distinguishing P. andersoni from other South American species in its genus. The venter, cheek spots, and eye spots of P. andersoni are cream to creamy gray. Its tail is covered in hair from the base to approximately 18% its length, and the remainder of the tail is bare. Approximately half the tail is colored brown or black and the remainder is not pigmented. The ears are black, oftentimes with a cream dot at the base of the pinna.

Although P. andersoni is similar in appearance to Metachirus nudicaudatus , P. andersoni females have fully developed pouches, while M. nudicaudatus females do not. Also, the entire tail of M. nudicaudatus is bare.

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

• Sexual Dimorphism
• male larger

Reproduction

One study of the number of Philander andersoni females with young at Jenaro Herrara, Peru found that females tend to reproduce in the wet season (January - March), when fruit production by local plants is high.

Little else is known about the reproductive behavior of P. andersoni , but this species was once classified under Philander opossum , which has been studied more extensively. Philander opossum females can have up to three litters in one year, each ranging between 1-7 young and averaging 3.4-4.24 young. Philander opossum individuals weigh approximately 9 g at birth and 50-75 g at weaning. The period between litters averages 90 days, and the ovarian cycle is interrupted by lactation, but not gestation. Weaning occurs at day 76 after birth, on average. Female P. opossum reach sexual maturity at 5-8 months in the wild and 15 months in captivity.

• Key Reproductive Features
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• viviparous viviparous

Few studies have been performed on P. andersoni parental investment, Philander opossum young stay in the nest 8-15 days post-weaning, and after this period the female is indifferent or aggressive to her young.

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

Lifespan/Longevity

Little is known about the lifespan of P. andersoni , but the average lifespan of Philander opossum is 2.5 years in the wild and 3.5 years in captivity.

Behavior

Typical of the Philander genus, Philander andersoni is a solitary, nocturnal species, and individuals spend most of their time on the ground. In fact, when captured individuals were released at two rainforest sites in Peru, most chose terrestrial escape routes over arboreal escape routes.

Species of the genus Philander act aggressively when threatened, and will open their mouths, hiss, and fight in response to threats. Little is known about nest building in this species, but a closely related species, Philander opossum , builds its nests on the ground, in burrows, or in low branches.

• Key Behaviors
• scansorial
• terricolous
• nocturnal nocturnal
• motile motile
• solitary solitary

Home Range

Little information is known about the home range sizes of P. andersoni , but P. opossum individuals are non-territorial, have home ranges that overlap, and 137-191 P. opossum can be found in one km^2. Philander opossum individuals also migrate and will stay in one area for less than a year.

Communication and Perception

Although little is known about P. andersoni communication and perception, it is known that the closely related P. opossum uses at least three sounds to communicate: a clicking sound, a hiss when threatened, and a squeak, which may be used as a mating call by females. 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.

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

Food Habits

Philander andersoni individuals are omnivorous. They will eat insects, other small invertebrates, eggs, and fruits.

• Primary Diet
• omnivore omnivore

• Animal Foods
• eggs
• insects
• terrestrial non-insect arthropods
• terrestrial worms

• Plant Foods
• fruit

Predation

There are no known predators of P. andersoni , but, like the closely related Philander opossum , it is most likely preyed upon by wild felids, wild mustelids, foxes, large owls, and large snakes. In fact, remains of P. opossum have been found in the feces of the viper Bothrops asper . Opossums of the species P. opossum are also occasionally consumed by humans in Guyana, and P. andersoni could also be a food source for humans.

Ecosystem Roles

Species in the genus Philander have been known to host many endoparasites including viruses, protozoans, fungi, roundworms (Nematoda), flukes (Trematoda), and tapeworms (Cestoda) and ectoparasites including lice (Mallophaga), fleas (Siphonaptera), mites, ticks, and chiggers (Acarina). Philander species are also a known reservoir for Trapanosoma cruzi , which causes trypanosomiasis in humans and animals.

In addition, since Philander species consume fruits, are mostly terrestrial, and move often, they are potential dispersers of seeds. One study by Medellin (1994) did find that the closely related Philander opossum does disperse seeds of Cecropia obtusifolia , a tree species important in succession of forests, into adequate germination sites such as light gaps, which other arboreal frugivores do not reach.

Economic Importance for Humans: Positive

It is unlikely that this species is of any positive economic importance for humans.

Economic Importance for Humans: Negative

Philander andersoni is unlikely to have a negative economic impact, but Philander species are a known reservoir for Trapanosoma cruzi , which causes trypanosomiasis in humans and animals.

Conservation Status

Philander andersoni is listed as a species of least concern by the IUCN Red List because it has a wide distribution, and thus an expected large population, and its distribution encompasses many protected areas.

Other Comments

All species in the genus Philander were long considered subspecies of Philander opossum , including Philander andersoni . Thus, current species-specific research on P. andersoni focuses on morphological and genetic differences between this species and the others in its genus, and most older information is classified under P. opposum. Little information currently exists that differentiates P. andersoni from P. opossum in behavior, reproduction, feeding habits, and habitat selection.

Additional Links

Encyclopedia of Life

Contributors

Rachel Cable (author), Animal Diversity Web Staff.

References

D'Andrea, P., R. Cerqueira, E. Hingst. 1994. Age estimation of the Gray Four Eyed Opossum, Philander opossum . Mammalia , 58/2: 283-291.

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

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

Medellín, R. 2004. Didelphimorphia (New World Opossums). Pp. 249-265 in Grzimek's Animal Life Encyclopedia , Vol. 12, 2nd Edition. Detroit: Gale Virtual Reference Library. Accessed April 04, 2013 at http://go.galegroup.com.proxy.lib.umich.edu/ps/i.do? id=GALE%7CCX3406700770&v=2.1&u=umuser&it=r&p=GVRL&sw=w .

Medellín, R. 1994. Seed Dispersal of Cecropia obtusifolia by Two Species of Opossums in the Selva Lacandona, Chiapas, Mexico. Biotropica , 26/4: 400-407.

Nowak, R. 2005. Walker's Marsupials of the World . Baltimore: The Johns Hopkins University Press.

Patton, J., D. Astua de Moraes. 2008. " Philander andersoni " (On-line). IUCN 2012: The IUCN Red List of Threatened Species. Accessed April 01, 2013 at www.iucnredlist.org .

Patton, J., M. da Silva. 1997. Definition of species of pouched four-eyed opossums (Didelphidae, Philander ). Journal of Mammalogy , 78/1: 90-102.

Patton, J., M. da Silva. 2007. Genus Philander Brisson, 1762. Pp. 27-35 in Mammals of South America . Chicago: The 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.