The earliest member of the horse family was the size of a?

The earliest member of the horse family, known as Hyracotherium or Eohippus, was about the size of a small dog, roughly 12 to 20 inches tall at the shoulder. This early ancestor lived around 50 million years ago and had a more primitive body structure, with multiple toes and a flexible, forest-adapted build. Over millions of years, horses evolved into larger, more efficient grazers suited for open grasslands.