What Is a Colt Horse?

Characteristics of Colts

A popular notion is that fillies are smarter than colts. Likewise, some people believe that fillies stand more quickly after birth and nurse sooner after they are born than fillies do. These are merely popular myths. Many people believe that colts are bolder than fillies, but a 2010 study suggests that this, too, is untrue. Like most mammalian males, colts tend to grow a bit faster than fillies—even moreso if they are gelded at a young age. This is because gelding—the practice of removing the colt's testes, also known as castration or neutering—refocuses the colt's reproductive growth into other aspects of development.

Other Horse-Related Definitions

The horse-racing world has a stricter definition of the word "colt": a young male horse between the ages of two and five. Races for colts and fillies are commonplace. After the age of five, colts are called either stallions or geldings. In a race, a filly may be any female horse younger than five years old. After the age of four, a filly is called a mare.

All young equids, including donkeys, ponies, mules, zebras, and onagers, share the definitions of "colt" and "filly." Thus, you might hear someone talking about a donkey filly or pony colt.

Colts in Popular Culture

The word "colt" comes from the Old English expression for "young ass." In Biblical times, the term was also used for young camels. It's similar to the Swedish kult, which referred to a young boar or piglet, or to a boy. The Danish kuld meant "offspring" or "brood" and was used as early as the 13th century as a term for a child.

In Classical Dictionary of the Vulgar Tongue (published in 1796), an old man who married or kept the company of a young girl was said to have "a colt's tooth in his head."