"The lack of a clear Proto-Indo-European word for 'donkey‘, given the presence of domesticated donkeys throughout most of the territory where horses were domesticated and where the Indo-European tribes must have lived, can be explained by assuming that *ekhwos was originally used with the meaning 'donkey‘ as well as 'wild horse; horse‘. ...[the PIE speakers lived in] Central and Eastern Asia, where paleozoological data show that the domesticated donkey is a recent introduction."