Evolution of The Horse

By Anna Genova

Evolution of The Modern Day Horse

10 million years ago over a dozen horse species roamed the earth, but that is not true for present day. We only have the modern day horse. This is because the climate started to change and the grassland began to expand so the horses evolved from small forest scavengers to large grazing animals of the plains. Because they are mostly found on flat plain areas they eat grass, weed, hay, etc. and are eaten by coyotes, wolves, bobcats, etc.


Ancestors of The Modern Day Horse

The ancestors of the horse are known as:
  • Mesohippus 45 kg
  • Merychippus 100 kg
  • Nannippus 75 kg
  • Equus 500 kg - modern day horse

The Mesohippus and Nannippus may have looked similar to the Equus but they were much smaller and could be found scampering around the forest. While Merychippus and Equus were found grazing in the plains. The organs of the smaller Mesohippus and Nannippus were probably much different than the larger Merychippus and Equus because their sizes were so varried and the 2 smaller species were use to eating foliage from the forest. Also, Mesohippus, Merychippus, and Nannipus did not have hooves like the Equus.



Other Species in Clade

Early horse species were similar to many different species for example:

Procamelus - a camel relative

Gomphotheriuma - distant relative of true elephants

Teleoceras - a hornless rhinoceros


Evolution Evidence

These are fossil records of the evolution of the horse(couldnt fit all pictures on here) - http://chem.tufts.edu/science/evolution/horseevolution.htm

The morphology of horses is still very similar they are just much larger with hooves. Their eating habits are different along with their organs so they can survive on their new eating habits.

Artificial selection has played a big part in horse evolution because breeders make horses for certain tasks so they breed the horses for certain things. such as racing or farming