Horses evolved from a foot tall, swamp dwelling, four toed horse called the __________.

The term that refers to the early ancestor of modern horses, which stood about a foot tall and dwelled in swampy areas, is Eohippus. This prehistoric horse is significant in the study of equine evolution due to its anatomical characteristics, such as having four toes on each foot and its small size, which were adaptations to a forested, marshy habitat.

Eohippus is recognized as one of the earliest members of the horse family, dating back to the Eocene epoch. The species shows key evolutionary features that led to the development of later horse breeds. Understanding Eohippus helps illustrate how horses have adapted over millions of years to different environments, culminating in the large, fast, and predominantly single-toed horses we see today, such as the genus Equus.

This evolutionary context is essential for grasping the principles of livestock selection and evaluation, as it emphasizes the importance of physical attributes and adaptations that have developed to suit various breeding and environmental criteria over time.