Philander olrogi

Geographic Range

Philander olrogi is known from only two localities in Bolivia, one in the Beni Department and the other in the Santa Cruz Department.

• Biogeographic Regions
• neotropical neotropical
  • native native

Habitat

Philander olrogi have been caught on the margins of lowland marshy areas forested mostly by palm trees.

• Habitat Regions
• tropical tropical

• Terrestrial Biomes
• forest forest

• Wetlands
• marsh marsh

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 olrogi has a head and body length of 235-291 mm, tail length of 260-307 mm, and weight of 284-550 g. It has short, dusty black or dark gray hair on the dorsum, paler coloration on the sides, and orange-buff on the venter. The venter coloration is more noticeable on the chest and fades towards the legs. The head is blackish brown from the brow to the muzzle, with distinct cream spots above the eyes and cream cheeks. The ears are cream at the base and pigmented black on the edges. They do not have the yellow hairs at the posterior base of the ears that many species in the Philander genus have. Males have darker coloration on the dorsum and more noticeable coloration on the ventrum, and females have reddish hairs near the pouch. The tail of P. olrogi is furred by short hairs for 20% from the base, pigmented blackish brown 75% from the base, and unpigmented or cream for the remainder.

Philander olrogi is sympatric with Philander opossum , and can be identified by the lack of yellow hairs behind the ears and by short hairs on the tail. Also, P. olrogi has a much more broad rostrum than all other species of the genus Philander .

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

Reproduction

Little is known about the reproductive behavior of P. olrogi , but this species was once classified under Philander opossum , which has been studied more extensively. Philander opossum has a year-round breeding season, but successful reproduction depends on food availability, so young are found mostly in the wet season. 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. olrogi parental investment, but 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. olrogi , but the average lifespan of Philander opossum is 2.5 years in the wild and 3.5 years in captivity.

Behavior

Species of the genus Philander are agile, quick opossums that are good climbers and swimmers, although they are mostly terrestrial. They are nocturnal and solitary. They 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 of P. olrogi , 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. olrogi 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

Few studies exist on the feeding habits of P. olrogi , but species in the genus Philander are omnivores, consuming small mammals, birds and their eggs, reptiles, amphibians, insects, freshwater crustaceans, snails, earthworms, fruits, and carrion.

• Primary Diet
• omnivore omnivore

Predation

There are no known predators of P. olrogi , 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. olrogi 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 olrogi 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 olrogi is listed as a data deficient species by IUCN Red List, as very few specimens have been found and little is known about its population sizes and habitat requirements. It may be threatened by habitat loss in Bolivia, and further research is required to determine its conservation status.

Other Comments

All species in the genus Philander were long considered subspecies of Philander opossum , including Philander olrogi . Thus, current species-specific research on P. olrogi 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. olrogi 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.

Flores, D. 2011. " Philander olrogi " (On-line). IUCN 2012: The IUCN Red List of Threatened Species. Accessed April 23, 2013 at www.iucnredlist.org .

Flores, D., R. Barquez, M. Díaz. 2008. A new species of Philander Brisson, 1762 (Didelphimorphia, Didelphidae). Mammalian Biology , 73: 14-24.

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. 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.

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