Here's why:
* It's about breed, not height: The difference between ponies and horses is primarily based on breed characteristics. Some breeds are naturally smaller and are considered ponies, while others are larger and are considered horses.
* Height varies within breeds: Even within a single breed, ponies and horses can range in height.
* The "pony" vs. "horse" distinction is somewhat fuzzy: There's no official standard that everyone agrees on.
General guidelines:
* Pony: Generally, a pony is under 14.2 hands (58 inches) tall.
* Horse: Typically, a horse is 14.2 hands or taller.
However, it's important to remember these are just guidelines. Some breeds like the Shetland Pony are always considered ponies even if they reach the 14.2 hand mark.
Ultimately, it's the breed that determines whether an animal is a pony or a horse, not just its height.