> Which creature has the scientific name of Equus ferus caballus?And the answer is: the horse. Photo courtesy: WIN-Initiative / Getty Images.Equus is a genus of mammals that includes horses, donkeys, and zebras. The Latinterm Equus ferus translates into "wild horse." When you add "callabus" to theend – Equus ferus callabus – that refers specifically to domesticated horses.Horses and humans have a relationship dating back many thousands of years. Infact, according to the American Museum of National History, horses have been onthe planet for over 50 million years. The first domesticated horses were likelybrought at the hand of Asian nomads some 4,000 years ago. Since then, horses are nearly all raised in domestication. While herds exist inpockets in almost every country in the world and every continent exceptAntarctica, their numbers pale in comparison to the some 400 breeds ofdomesticated horses used for everything from tractor pulling to competitiveracing. Wild and domestic alike, horses are herbivores. They typically spend most of theday grazing, as their digestive systems are far from efficient and require largeintake to transfer sufficient nutrients. While most larger horses requiremultiple, substantial feeds a day, there are some breeds of pony and mini-horsethat need much less. Average-sized horses eat approximately 15 to 20 pounds offood per day whereas mini horses eat just 2 to 4 pounds. Did you know?Half of all free-ranging horses in the United States live in Nevada. A region ofthe state called The Virginia Range is home to around 2,000 feral horses (feralis used to indicate horses that are the descendants of once-tame animals, buthave run free for generations).