The story
So called, possibly, from the white underside of the tail of most species which, when arched over the back, is reminiscent of similar behavior by pronghorn antelopes.
Etymology from Wiktionary, CC BY-SA 4.0.
antelope squirrel
Today it means: Any of a group of sciurids of the genus Ammospermophilus, found in the desert and dry scrub areas of the southwestern United States and northern Mexico. Full definition →