Nesoryzomys indefessus indefessus Thomas, 1899:280

Indefatigable Galápagos mouse, Santa Cruz nesoryzomys, Indefatigable rice rat



Taxonomy & Nomenclature

Synonym/s: Oryzomys indefessus Thomas, 1899:280; Nesoryzomys sp. nov. A (Turvey, 2009:52; Turvey & Fritz, 2011:SI:8)


Conservation Status


Last record: 1934 (Fisher & Blomberg, 2012; Lee et al., 2017)

IUCN RedList status: Extinct



Baltra (= South Seymour) & Santa Cruz (=Indefatigable), Galápagos Islands, Ecuador


Biology & Ecology




MCZ 27036 (skin and skull; female)
MCZ 27037 (skin and skull; female)






Original scientific description:

Thomas, Oldfield. (1899). Descriptions of new neotropical mammals. Ann. and Mag. Nat. Hist. ser. 7, v. 4, 1899, p. 280.


Other references:

Bininda-Emonds, O.R.P., Cardillo, M., Jones, K.E., MacPhee, R.D.E., Beck, R.M.D., Grenyer, R., Price, S.A., Vos, R.A., Gittleman, J.L. & Purvis, A. (2007). The delayed rise of present-day mammals. Nature 446, 507-512.

Dowler, R.C., Carroll, D.S., and Edwards, C.W. 2000. Rediscovery of rodents (Genus Nesoryzomys) considered extinct in the Galapagos Islands. Oryx 34(2): 109-117.

Fisher, Diana O. and Blomberg, Simon P. (2012). Inferring Extinction of Mammals from Sighting Records, Threats, and Biological Traits. Conservation Biology 26(1): 57-67.

Freudenthal, M. and Martín-Suárez, E. (2013). Estimating body mass of fossil rodents. Scripta Geologica 145: 1-130. [0.083-0.129 kg estimate]

Goodwin, Harry A. and Goodwin, J. M. (1973). List of mammals which have become extinct or are possibly extinct since 1600. Int. Union Conserv. Nat. Occas. Pap. 8: 1-20.

Harris, D.B. (2006) Introduced black rats abd endemic Galapagos rice rats: competition, coexistence and conservation. A thesis submitted for the degree of Doctor of Philosophy. Linacre College, Oxford.

Harris, D.B., MacDonald, D.W. (2007) Population ecology of the endemic rodent Nesoryzomys swarthi in the tropical desert of the Galapagos Islands. Journal of Mammalogy 88 (1): 208-219.

Hopkins, S. B. (2008). Reassessing the mass of exceptionally large rodents using toothrow length and area as Proxies for body mass. Journal of Mammalogy 89, 1: 232-243.

Jiménez-Uzcátegui, G., Milstead, B., Márquez, C., Zabala, J., Buitrón, P., Llerena, A., et al. (2007) Galapagos vertebrates: endangered status and conservation actions. Galapagos Report 2006–2007. Charles Darwin Foundation, Puerto Ayora, p. 104–110.

Jiménez-Uzcátegui, Gustavo and Snell, Howard L. (2014). CDF Checklist of Galapagos Mammals - FCD Lista de especies de Mamíferos Galápagos. In: Bungartz, F., Herrera, H., Jaramillo, P., Tirado, N., Jiménez-Uzcátegui, G., Ruiz, D., Guézou, A. & Ziemmeck, F. (eds.). Charles Darwin Foundation Galapagos Species Checklist - Lista de Especies de Galápagos de la Fundación Charles Darwin. Charles Darwin Foundation / Fundación Charles Darwin, Puerto Ayora, Galapagos: Last updated: 24 Jan 2014

Lee, T. E., Fisher, D. O., Blomberg, S. P. and Wintle, B. A. (2017). Extinct or still out there? Disentangling influences on extinction and rediscovery helps to clarify the fate of species on the edge. Global Change Biology 23(2): 621-634.

Musser, G.G. and Carleton, M.D. 1993. Family Muridae. In: D.E. Wilson and D.A. Reeder (eds), Mammal species of the world: A taxonomic and geographic reference, pp. 501-736. Smithsonian Institution Press, Washington, DC, USA.

Musser, G.G. and Carleton, M.D. 2005. Superfamily Muroidea. In: D.E. Wilson and D.A. Reeder (eds), Mammal Species of the World: a geographic and taxonomic reference, pp. 894-1531. The John Hopkins University Press, Baltimore, USA.

Orr, R. T. (1938). A new rodent of the genus Nesoryzomys from the Galapagos Islands. Proceedings of the California Academy of Science, 4th Series, 23: 303-306.

Patton, J. L., and M. S. Hafner. 1983. Biosystematics of the native rodents of the Galapagos Archipelago, Ecuador. Pp. 539-568, in Patterns of evolution in Galapagos organisms (R. I. Bowman, M. Benson, and A. E. Leviton, eds.). American Association for the Advancement of Science, Pacific Division, San Francisco, CA, 568 pp.

Snell, H.L., Tye, A., Causton, C.E. & Bensted-Smith, R. (1999) Estado y amenazas de la biodiversidad terretre de Galápagos. Visión para la biodiversidad de las islas Galápagos. Fundación Charles Darwin para las islas Galápagos y WWF. Puerto Ayora, Galápagos.

Steadman, David W., Stafford, Thomas W. Jnr., Donahue, Douglas J. and Jull, A. J. Timothy. (1991). Chronology of Holocene vertebrate extinction in the Galápagos Islands. Quaternary Research 36(1): 126-133.

Tirira, D., Dowler, R., Boada, C. and Weksler, M. (2008). Nesoryzomys indefessus. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. ( Downloaded on 29 July 2013.

Tirira, D.G. & Weksler, M. 2019. Nesoryzomys indefessus. The IUCN Red List of Threatened Species 2019: e.T14708A22390443. Accessed on 20 June 2022.

Turvey, Samuel T. (2009). Holocene mammal extinctions, pp. 41-61. In: Turvey, Samuel T. (ed.). Holocene Extinctions. Oxford, UK & New York, USA: Oxford University Press. xii + 352 pp.

Turvey, Samuel T. and Fritz, Susanne A. (2011). The ghosts of mammals past: biological and geographical patterns of global mammalian extinction across the Holocene. Philosophical Transactions of the Royal Society B: Biological Sciences 366(1577): 2564-2576. [Supplementary Information]


<< Back to the Rodents database