Wild Horses

Despite the refrain of the Rolling Stones' tune, wild horses are a rare thing in today's world. The horse was extinct in the western hemisphere before the Spanish "discovered" the Novus Orbis. In the United States, the mustang is considered a wild horse by some, but they are actually descendants of domesticated equine left by the conquistadors. 

One wild breed that still wanders the Asian plains is the onager. This sturdy animal has suffered loss of habitat and other intrusions by man, but still survives. They are nearly impossible to domesticate and are known for their vicious rear kicks. So much so, that the Romans called their catapults onagers because of the dangerous kick-back these small ballistae produced. The name onager derives from the Greek word for ass. 

Even the ancients knew that be it an animal or a siege weapon, it's not smart to stand behind a wild ass. - as ever BB