Unlike the icon on your stamp Collin
you are very quick

I very well may be wrong but the African wild ass,
features on very few stamps, one I think.
Then we have the Indian wild ass "Equus Hemionus"

The interesting thing here is, according to James A Mitchener's
American novel "Centennial" Equus, or the horse, originated in the Americas, at the time of the "first" rocky mountains range.
It was a little bit larger than a rabbit, and had 3 toes.
By the time humans (The Spanish) imported the horse into the Americas
in 1500, by doing so, the horse had circumnavigated the world.