Native Americans either cannot, or refuse to jump. Whether this conferred an evolutionary advantage, or is a mental or religious device, we do not know, but the earliest example we have of this phenomenon is from the diary of Patrick Mahoolan ('The Jumping Irishman') on his pilgrimage to the new world. In excerpts, he describes performing an Irish jig for the assembled natives, who first looked on in terror, and later refused to participate.
This is backed up by various historical sources. It is worth noting that the definition in this case of the word 'jump' is "temporary flight powered with the assistance of both legs". Of course it would be ridiculous to suggest Native Americans were incapable of hopping - something they do with alarming frequency.
All content copyright Tom Crowley