Sigmodon fossil map
Where fossils of Sigmodon have been found, shown on the Earth as it looked about 0 million years ago and on today’s map.
Dots are fossil collections recorded in the Paleobiology Database. The “then” view moves today’s fossil sites back to their positions 0 million years ago (the time slice nearest the median age of the fossils) using the Merdith et al. (2021) plate model; positions are approximate. Open on the timeline map →
| Group | Early mammals |
|---|---|
| Lived | 9.4 million years ago to the present (Tortonian to Holocene) |
| Periods | Neogene, Quaternary |
| Family | Cricetidae |
| Named by | Say and Ord 1825 |
| Fossil records | 416 occurrences at 85 locations (PBDB) |
| Found in | United States, Mexico, Venezuela, Peru, Panama |
| Rock formations | txn:41724, Palm Spring, "unnamed sandstone", St. David, San Timoteo, Gila Conglomerate |
About Sigmodon
A cotton rat is any member of the rodent genus Sigmodon. Their name derives from their damaging effects on cotton as well as other plantation crops, such as sugarcane, corn, peanut and rice. Cotton rats have small ears and dark coats, and are found in North and South America. Members of this genus are distributed in the Southwestern United States, Mexico, Central America, and South American countries of: Venezuela, Ecuador, Colombia, Peru, Brazil, Guyana, and Suriname. Many of the species are found in Mexico.
They are primarily herbivores. The molars of cotton rats are S-shaped when viewed from above. The genus name literally means S-tooth.
Sigmodon hispidus was the first model organism to be used in polio research.
Text in “About” is quoted from the Wikipedia article Cotton rat (revision 1248778825), licensed under CC BY-SA 4.0; introduction excerpted verbatim, formatting removed. Ages, family, authority and fossil records: Paleobiology Database, accessed 23 October 2026. Ages are those of the rock layers the fossils were found in. Wikidata: Q609460.
