Animal Diversity Web

Geographic Range

The Roraima mice, or Podoxymys roraimae are found only in the mountains of Venezuela where it borders of Brazil and Guyana. While their habitat is on the border of these three countries, the only specimens were found in Venezuela. Podoxymys roraimae inhabit an area of 43 square km on the summit of Roraima Mountain and an area of 3 square km on the summit of Wei-Assiputepui in Brazil. (Lew and Ojasti, 2015; Patton, 2018)

• Biogeographic Regions
• neotropical
  • native

Habitat

Podoxymys roraimae occupy only forest and rainforest biomes of Venezuelan Mountains. The lush habitat houses dense vegetation and adequate humidity for the tropical plants. Podoxymys roraimae are found at minimum elevations of 1,500 meters and maximum elevations of 2,600 meters. Scientists infer that P. roraimae live on or in the ground (Patton, 2018). (Lew and Ojasti, 2015; Patton, 2018)

• Habitat Regions
• tropical
• terrestrial

• Terrestrial Biomes
• forest
• rainforest

• Range elevation

  1,500 to 2,600 m

  to ft

• Average elevation

  2,050 m

  ft

Physical Description

Podoxymys roraimae are described as small (7 to 10 cm in length), though average mass is unknown. The fur of P. roraimae is usually grey or black with some occasional cinnamon coloring around the face. Their fur is smooth and long and shorter on the skull. The legs and tail are bare and usually brown or grey in coloring. The face is elongated with small dark eyes and short, rounded ears that are covered in fine black hairs. Both front and back paws have long nails that indicate some adaptation for digging (Perez-Zapata et al, 1992). The coloring and markings of Roraima mice do not differ according to sex or age. Podoxymys roraimae are the only species within the genus and thus are unique in many physical characteristics. (Leite, et al., 2015; Lew and Ojasti, 2015; Perez-Zapata, et al., 1992)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range length

  7 to 10 cm

  2.76 to 3.94 in

Reproduction

Mating systems in Podoxymys roraimae are unknown. (Perez-Zapata, et al., 1992)

All known data of Podoxymys roraimae concerning reproduction is strictly from a cellular standpoint. It is known that P. roraimae have low diploid numbers, 2n = 14-18 (Perez-Zapata et al., 1992). However, any information on mating, birthing, and the raising of young is unknown. Due to the the severe isolation of P. roraimae it has made it very challenging for scientists to observe them in their natural habitat and there have been no successful reproduction trials in captivity. (Perez-Zapata, et al., 1992)

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

• Breeding interval

  unknown

• Breeding season

  unknown

Lifespan/Longevity

Podoxymys roraimae is a rare species that has not been studied thoroughly enough and thus their true lifespan is unknown. No individuals have been kept in captivity or have been studied for long periods of time in the wild. (Anthony, 1929)

Behavior

Podoxymys roraimae has not been studied in its natural habitat or in captivity so the behavioral patterns are unknown. Most attempts at capturing P. roraimae resulted in the capture of Rhipidomys macconnelli, which is also known as the MicConnells climbing mouse (Lew, Ojasti 2015). All seven specimens studied so far have not been alive. (Lew and Ojasti, 2015; Perez-Zapata, et al., 1992)

• Key Behaviors
• terricolous
• fossorial
• nocturnal
• motile

• Range territory size

  43 to 46 km^2

Home Range

The range of habitat for the Podoxymys roraimae is limited to the summit of Mount Roraima, which has an average area of 43 square kilometers and the summit of Wei-Assiputepui with an average area of 3 square kilometers. (Lew and Ojasti, 2015)

Communication and Perception

All communication and perception information on P. roraimae is unknown. (Anthony, 1929; Eisenberg, 1989)

• Perception Channels
• visual
• tactile
• chemical

Food Habits

Podoxymys roraimae are active nocturnally. They have elongated front claws, which scientists infer are used for digging (Lew and Ojasti, 2015). When captured, the different specimens of P. roraimae had insects, earthworms, and various plants in their stomachs, which is evidence that P. roraimae are omnivores (Perez-Zapata et al., 1992). (Lew and Ojasti, 2015; Perez-Zapata, et al., 1992)

• Primary Diet
• carnivore
  • insectivore
  • vermivore
• herbivore
  • folivore
• omnivore

• Animal Foods
• insects
• terrestrial worms

• Plant Foods
• leaves

Predation

Podoxymys roraimae has deep brown fur, used for camouflage against the dark soil of their habitat (Perez-Zapata et al., 1992). They have long front claws, which are likely used for digging deep within the ground. However, it is not known whether or not these claws are used for hiding or foraging for food (Lew and Ojasti, 2015). There is little else known about the predators of this species. (Anthony, 1929; Lew and Ojasti, 2015; Perez-Zapata, et al., 1992)

• Anti-predator Adaptations
• cryptic

• Known Predators

  • There are no known predators of Podoxymys roraimae

Ecosystem Roles

There is no specific information of the ecological role of Podoxymys roraimae, however it is inferred that they are prey to animals in the area (Alvarado-Serrano and D'Elia, 2013). It is also known that P. roraimae hunt insects, so scientists have used this as evidence to show that they may help with insect control (Verbeke, 2015). (Alvarado-Serrano and D'Elia, 2013; Verbeke, 2015)

• Ecosystem Impact
• soil aeration

Economic Importance for Humans: Positive

Podoxymys roraimae is an important member of the ecosystems they inhabit but have no other known economic importance for humans. (Lew and Ojasti, 2015)

• Positive Impacts
• ecotourism

Economic Importance for Humans: Negative

There is no known adverse effects of Podoxymys roraimae on humans. (Eisenberg, 1989)

Conservation Status

Podoxymys roraimae is listed as vulnerable on the IUCN website and is not listed on any others. However, P. roraimae may be vulnerable because of the tourism that takes place within its limited habitat (Lew and Ojasti, 2015). Tourism disrupts their habitat and potentially introduces nonnative species that can harm the Roraima mouse population (Lew and Ojasti, 2015). (Lew and Ojasti, 2015; Patton, 2018)

• IUCN Red List

  Vulnerable

Other Comments

The discovery of Podoxymys roraimae was completely accidental and scientists are still researching many basic elements of this species. The first discovery occurred in 1929 with H.E. Anthony and was not cited again until 1989 with J. Eisenberg. Podoxymys roraimae are one one of the rarest and most geographically isolated species in the world. (Verbeke, 2015)

Contributors

Imani Vontoure (author), Colorado State University, Nathan Dorff (editor), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Alvarado-Serrano, D., G. D'Elia. 2013. A new genus for the Andean mice Akodon latebricola and A. bogotensis (Rodentia: Sigmodontinae). Journal of Mammalogy, 5: 995-1015. Accessed February 08, 2021 at https://watermark.silverchair.com/94-5-995.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAArcwggKzBgkqhkiG9w0BBwagggKkMIICoAIBADCCApkGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMvPZ2cqkR071bs6bOAgEQgIICakWQZTnnP_MP_P3Da8HyyZBCKTCjPywDHRtwRmtIXFv4MVmKt06CyWrbKVl6NdWvHNGlWSzH4ThUd9xU1fhdQ2le4T9_pCDIGEhhT0Tnad8q9YNUDcxk-Oxjt65-mzaw7vus03bwfSo7MKl5MI52NZHZT252gnE2c2YxIwT5Hc2wpgiNz8sHokgncWWW9Ld--MAy1VV_DjjZKIe-eZwvR3RXmTxz5za2nomE26-vz3Ff2GXj781PgSiHvdDYjYjK4P7dI6fHd2RQAaLoXfXhAeunP4loKOXR7c32Q-Qr5aOHlsSejWx8O49xWHabwqwuD3k-T2W35NTrL36yHTo50_aQD0l-JLpoEVGqs21Yi08naHXoDw4ckXF9uOMMi6Q1XhpRZkqf_o0yBOxNvY4IBzvXaF-h-jy4e0qpIvE-CxLu_U5n7udQ4_pu4qTe_Ijad8haWQt67UHfBgDorUJEF1Ce_pWTVTLcfrSUx0pyI-ZnimAC7qjFTZNScuYPi_lz9Ej6Hm4u7oiD8bG8iw4DZLYsPKxK1NY6zFBpm1W_eRGeu5vPIUeo_SPy2H3655NueTnvN_CnvqKsn3f6zAW8rVxoIVhxRr9gyMyHgTF5fp9qlXAlgWkUIFC0UeIVBXYZn85f2dn46BUwQ0C8errElXdmoWVgntIbuox6lFCOeibmsNJF9RAppcl0bjpGCQBqQsfwjoioxJUSl8CHG0Thvk3A5LZRt6YZtk67TkxqkF0Ed8Bw8A-0lk4Xy7nxLLVq_u1S_LkcugS4f9wlIfvnvSERWobb5WISn3mXKheipP_Ihll8NDklYFH5Qw.

Anthony, H. 1929. Two new genera of Rodents from South America. American Museum Novitates, 383: 1-6. Accessed February 08, 2021 at http://apps.webofknowledge.com.ezproxy2.library.colostate.edu/full_record.do?product=ZOOREC&search_mode=GeneralSearch&qid=1&SID=5DnGC7tpEtpRBi9grHq&page=1&doc=3.

Eisenberg, J. 1989. Mammals of The Neotropics. Chicago and London: University of Chicago Press.

Hollowell, T., R. Reynolds. 2005. Checklist of The Terrestrial Vertebrates of The Guiana Shield. National Museum of Natural History: Biological Society of Washington. Accessed February 08, 2021 at https://naturalhistory.si.edu/sites/default/files/media/file/bswa13all.pdf.

Leite, Y., P. Kok, M. Weksler. 2015. "Evolutionary affinities of the ‘Lost World’ mouse suggest a late Pliocene connection between the Guiana and Brazilian shields" (On-line). Wiley Online Library. Accessed February 08, 2021 at https://onlinelibrary-wiley-com.ezproxy2.library.colostate.edu/doi/full/10.1111/jbi.12461.

Lew, D., J. Ojasti. 2015. "Ratón del Roraima, Podoxymys roraimae" (On-line). Research Gate. Accessed February 08, 2021 at https://www.researchgate.net/publication/309718780_Raton_del_Roraima_Podoxymys_roraimae.

Pardinas, U., C. Canon, C. Galliari, J. Brito, N. Bernal Hoverud, G. Lessa, J. De Oliveira. 2020. Gross stomach morphology in akodontine rodents (Cricetidae: Sigmodontinae: Akodontini): a reappraisal of its significance in a phylogenetic context. Journal of Mammalogy, 3: 835-857. Accessed February 08, 2021 at http://apps.webofknowledge.com.ezproxy2.library.colostate.edu/InterService.do?fromPID=ZOOREC&product=UA&toPID=UA&returnLink=http%3a%2f%2fapps.webofknowledge.com%2ffull_record.do%3fhighlighted_tab%3dZOOREC%26last_prod%3dZOOREC%26excludeEventConfig%3dExcludeIfFromFullRecPage%26search_mode%3dGeneralSearch%26qid%3d1%26log_event%3dyes%26product%3dZOOREC%26SID%3d5DnGC7tpEtpRBi9grHq%26viewType%3dfullRecord%26doc%3d3%26page%3d1&srcDesc=RET2ZOOREC&SID=5DnGC7tpEtpRBi9grHq&qid=14&action=forward&highlighted_tab=UA&last_prod=ZOOREC&excludeEventConfig=ExcludeIfFromFullRecPage&search_mode=CitingArticles&queryNatural=no&fromMiniSummary=CitingArticles&doc=1&URL=%2Ffull_record.do%3Fsearch_mode%3DMostRecentCitingArticles%26qid%3D14%26page%3D1%26excludeEventConfig%3DExcludeIfFromMostRecent%26product%3DUA%26SID%3D5DnGC7tpEtpRBi9grHq%26colName%3DWOS%26recordID%3DWOS%3A000593258400019%26doc%3D1.

Patton, J. 2018. "IUCN Red List of Threatened Species" (On-line). Accessed February 08, 2021 at https://www.iucnredlist.org/species/17831/22390812.

Perez-Zapata, A., D. Lew, M. Aguilera, O. Reig. 1992. "New data on the systematics and karyology of Podoxymys roraimae (Rodentia, Cricetidae)" (On-line). Web of Knowledge. Accessed February 08, 2021 at https://www.zobodat.at/pdf/Zeitschrift-Saeugetierkunde_57_0216-0224.pdf.

Verbeke, R. 2015. "Very Rare Mouse Found in the Mighty Tepuis of the ‘Lost World’" (On-line). Accessed February 08, 2021 at https://www.naturalsciences.be/en/news/item/2628.