Millions of years ago, there were tropical forests across much of North America. Hyracotherium was the earliest known ancestor of the horse that was believed to have lived in the tropical forests. The fossil of Hyracotherium was about the size of a modern dog. In contrast to the large grinding teeth of the modern horse, the fossil of Hyracotherium had small teeth. Based on this information about Hyracotherium, which of the following is most likely true?