Hippo/Hippopotamus. =]
yes, a hippopotamus is sometimes referred to as a river horse.
Obis Horse
horse soldiers
a stalion.
If you ever see the word horse after another word, that is usually the breed. Pampas horse is probably a breed, horse is just a general word, the breed is more specific.
Rider Up!
Flying donkey
longshot, dark horse
Another word for mare would be filly
Charger is one such word. Champion is another one often associated with a horse.
If you mean another word for "Quarter Horse", there aren't any others. A Quarter Horse is a breed of horse.
mount