A pony does not "become a horse." Contrary to popular belief, a pony is NOT a baby horse, but rather an entirely different species.
A baby pony grows up to be an adult pony, and a baby horse (a 'filly' if female, a 'foal' if male) grows up to be an adult horse ('stallion' if male and not gelded, a 'gelding' if male and gelded, and a 'mare' if female.) The non-gender specific term for a baby horse is a 'colt'.
I assume that your question was meant to be, "when does a baby horse become an adult?" and the answer to that is indefinite. Generally, horses begin 'breaking in' (being trained to wear tack and carry riders) at sometime over 2 years. The general point at which horses reach sexual maturity is around 2 and a half years, though this varies between different genders.
Yes, they are breeds of horses that do not grow tall.
They are ponies!
they are horses but most people think they are ponies
Ethiopia has a mixture of horses, the most common ponies are Abyssinian ponies. I am not sure about Horses, but Ponies I am :D
Yes, stallions are grown male horses, ponies a kind of horse that never grow to the size of a full grown horse
The horses and ponies are mostly welsh cobs and welsh ponies.
The difference between horses and ponies are very easy to see in most breeds. Ponies are normally shorter and stockier than horses. A pony'smaximum height is 14.2hh.
All horses AND ponies are herbivores.
A pony is a sub-species of horses. Basically you get ponies when you breed horses rated as ponies.
Minis and Ponies. Light horses. Draft horses.
by ponies i hope that meant horses? and posiedon god of the sea created horses. there is no god of horses but, posiedon was the god to make them.
Most ponies look just like horses, just a little smaller.