Castoroides fossil map
Where fossils of Castoroides 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 | 9.4–0.0117 million years ago (Tortonian to Late Pleistocene) |
| Periods | Neogene, Quaternary |
| Family | Castoridae |
| Named by | Foster 1838 |
| Fossil records | 320 occurrences at 139 locations (PBDB) |
| Found in | United States, Canada |
| Rock formations | txn:41534, Bermont, McPherson, Fort Thompson, Kingsdown, "Crooked Creek" |
About Castoroides
Castoroides (from Latin castor (beaver) and -oides (like)), or the giant beaver, is an extinct genus of enormous, bear-sized beavers that lived in North America during the Pleistocene. Two species are currently recognized, C. dilophidus in the Southeastern United States and C. ohioensis in most of North America. C. leiseyorum was previously described from the Irvingtonian age but is now regarded as an invalid name. All specimens previously described as C. leiseyorum are considered to belong to C. dilophidus.
Text in “About” is quoted from the Wikipedia article Castoroides (revision 1377859249), 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: Q1866419.
