A polo pony is a horse used in the game of polo. They may be of any breed or combination of breeds, though many have a significant amount of Thoroughbred breeding. They are called "ponies", but that is a reference to their agile type rather than their size; almost all are horse-sized. They require considerable training and ongoing conditioning, and because each rider requires at least two horses in a single match, this can be a considerable expense. When playing, polo ponies have their manes roached and tails braided so that there is no danger of being tangled in the mallet.