Equine Science Mrs. Fahey History of the Horse Equine Science Mrs. Fahey

Horse Classification KINGDOM- Animalia PHYLUM- Chordata (having a spinal chord) CLASS- Mammalia ORDER- Perissodactyla FAMILY- Equidae GENUS- Equus SPECIES- Caballus

Evolution of the Horse Today's horses represent just one tiny twig on an immense family tree that spans millions of years. All the other branches of the horse family, known as Equidae, are now extinct. The earliest known horses evolved 55 million years ago and for much of this time, multiple horse species lived at the same time, often side by side.

Eohippus The origin of equines can be traced to the Eocene period, between 60 and 50 million years ago. Eohippus or Dawn Horse Size of a Cocker Spaniel 14 inches at the shoulder Weighed about twelve pounds

Eohippus Four toes on the front legs and three on the back Padded like a dogs and allowed easy movement over wet ground. These toes and pads are now the ergots and splint bones found on the legs of the modern horse.

Eohippus Eohippus was a browsing animal that lived on soft leaves growing on low shrubs. He was well equipped to survive in what were then the semi-tropical forests of the U.S. Midwest.

Hypohippus Three toes Ate soft leaves 18 to 9 million years ago

Horses and Toes Over millions of years, many horse species lost most of their side toes. The middle toe evolved into a single large hoof, while the other toes became smaller and ultimately functionless.

Dinohippos Single Hoof

Why is this One Hoof Important? What's the connection between hooves and grazing? Hooves and long legs help horses run farther and faster on the open prairie. Helps them flee from predators and find fresh grass for grazing. In the forest, where the ground is softer, many horses retained three toes.

So Why the Change? Two major changes in climate affected the evolution of early horses. 55 million years ago, global temperatures abruptly rose by 5 to 10 °C (9 to 18 °F) Much of North America turned into a warm, wet, subtropical forest—just like the Brazilian Amazon rainforest. Small, leaf-eating horses thrived.

Extinction About 10,000 years ago, horses became extinct in North America and South America. Equus, the ancestor of all horses today, survived only in Eurasia and Africa.

Extinction So what ended their 55-million-year run in North America? The prime suspects are changes in the environment disease over hunting by humans who likely killed them for food.

Modern Day Horses Przewalski's Horse also known as the Asian Wild Horse or Mongolian Wild Horse, or Takhi, is the closest living wild relative of the domestic horse.

Domestication Horses were first domesticated as draft animals on the Eurasian Steppes in the Near East between 4500 and 2500 B.C. It was at this time the people of that area adopted a nomadic way of life. They had already domesticated dogs, cows, sheep, and goats, but they needed a larger animal to carry their belongings.

Domestication The horse became their sole livelihood -- he provided transportation, milk, meat and skins. By 1000 B.C., domestication had spread through Europe, Asia and North Africa.