Rhea fossil map
Where fossils of Rhea 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 | Prehistoric birds |
|---|---|
| Lived | 23.04 million years ago to the present (Aquitanian to Holocene) |
| Periods | Neogene, Quaternary |
| Family | Rheidae |
| Named by | Brisson 1760 |
| Fossil records | 17 occurrences at 16 locations (PBDB) |
| Found in | Argentina, Brazil, Bolivia |
| Rock formations | txn:39283, Nuapua, Aisol, Ituzaingo, Epecuén |
About Rhea
The rhea ( REE-ə), also known as the ñandú ( nyan-DOO) is a South American ratite (flightless bird without a keel on the sternum bone) of the order Rheiformes. Rheas are distantly related to the two African ostriches and Australia's emu (the largest, second-largest and third-largest living ratites, respectively), with rheas placing just behind the emu in height and overall size.
Most taxonomic authorities recognize two extant species: the greater, or American, rhea (Rhea americana); and the lesser, or Darwin's, rhea (Rhea pennata). The International Union for Conservation of Nature (IUCN) classifies the puna rhea as another species instead of a subspecies of the lesser rhea. The IUCN currently rates the greater and puna rheas as near-threatened in their native ranges, while Darwin's rhea is of least concern, having recovered from past threats to its survival. In addition, the feral population of the greater rhea in Germany appears to be growing. However, control efforts are underway and seem to succeed in controlling the birds' population growth. Similarly to ostriches and emus, rheas are fairly popular livestock and pets, regularly kept and bred on farms, ranches, private parks, and by aviculturists, mainly in North and South America and Europe.
Text in “About” is quoted from the Wikipedia article Rhea (bird) (revision 1379735935), 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: Q19171.