Smithsonian National Museum of Natural History, North American Mammals
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Oryzomys nelsoni

Nelson's Oryzomys

Order: Rodentia
Family: Cricetidae


Conservation Status: Extinct.

This rice rat is probably extinct, and if so, the common house rat, Rattus rattus, is probably to blame. Extensive trapping efforts in 1899 resulted in the capture of only a few Nelson's Oryzomys, and all efforts to find this rat in the last 15 years have met with failure. Oryzomys nelsoni lived in a damp area near the highest point of Maria Madre Island, and probably fed on seeds, fruit, weeds, small fish, and invertebrates. They were similar to Oryzomys couesi, a rice rat that lives on the mainland, but with larger, heavier skulls and enough other differences for scientists to decide they were a separate species. The Mexican government lists Nelson’s Oryzomys as threatened, but it will be a surprise if one is ever seen alive.

Range: Total Length: 324, 344, 320 mm; Tail: 190, 191, 185 mm


Merriam, C.H., 1898. Proceedings of the Biological Society of Washington, 12:15.


Mammal Species of the World

Distribution of Oryzomys nelsoni