what is a young female horse called

A young female horse is called a filly. A filly is a female horse under four years old. In some nations, such as the United Kingdom and the United States, the world of horse racing sets the cutoff age for fillies as five. Once a filly is weaned, it may be called a weanling filly, and when it reaches the age of one, it may be called a yearling filly. After that age of two, it may be a two or three-year-old filly, but it wouldn’t be uncommon to hear a young female horse referred to as a young mare, even though this isn’t strictly correct.