Skip to main content


Merychippus illustration with leg detail
Horse evolution is a pretty fascinating thing, especially because it is so well documented in the fossil record. The earliest horses date back to Hyracotherium nearly 55 million year ago, and in the millions of years since that tiny toed creature appeared, horses have transitioned and evolved to become the creatures we know today.

Today's animal, Merychippus, lays somewhere near the end of the horse's story. Living between 20-10 million years ago, it is considered one one of the first "True Equines." This particular genus included horses that looked very much like our modern ones. They had only one hoof that touched the ground, as the modern horse does, but they still possessed two vestigial side toes positioned higher up on the leg. Nonetheless, they ran in a way similar to what we know now.

Aside from looking like a strange-legged modern horse, Merychippus is also notable because it is the first horse to have grazing teeth. The teeth of Merychippus suggest that it ate grass rather than browse on branches as earlier horses did. It's name actually means "ruminant horse," because its teeth resemble those of ruminant ungulate. Merychippus, however, did not have a ruminant digestive system, nor do any other horses.

It is believed that Merychippus is the direct ancestor to the other late Miocene horses, including  members of the Hipparion genus which lived until around 700,000 years ago.

Status :  Extinct for approximately 10 million years
Location : North America
Size : Height 35in (89cm)
Classification : Phylum : Chordata -- Class : Mammalia -- Order : Perissodactyla
Family : Equidae -- Genus : Merychippus


  1. As a horse lover this is an interesting post. Diane



Post a Comment

Popular posts from this blog

Bornean Orangutan

The Bornean Orangutan is one of two extant Orangutan species in the world. It is the third largest primate (after Gorillas) and is the largest primarily tree-dwelling animal in the world. Males are substantially larger than females, and average at around 165lbs. Bornean Orangutans are largely solitary. A handful might live within a small range but they will seldom interact with one another. Males and females only meet up to breed, which happens only once every several years. A young Orangutan will stay with it's mother for about five years, and the females tend to go about eight years between births. That is the longest interim period of any animal! Sadly, the Bornean Orangutans are in a lot of trouble. They need large forests in order to thrive, and deforestation and habitat degradation has left many homeless. They are also hunted for meat and for traditional medicines. Conservation areas are being established to help these guys in the wild, and it is believed that there are a

10 Years?!

My goodness! It's been 6 years since I went on hiatus, and now more than 10 years since AaD was born, and what a world we've moved in to! Animal a Day is coming back- but in the meantime, check us out on Facebook, for your daily dose of #BIRDNEWS


For anyone who was counting, yesterday was our birthday-- four years! Four years filled with animals from A to Z, more than 1,100 of them! I can't thank my readers enough, it's been wonderful! And in celebration of that milestone... I'm taking a break. Hopefully not forever, but for a little bit at least. In the mean time I plan on getting a new layout out, along with some updates to some of the older articles. I'll post updates here and on the Facebook page, I'm also brainstorming some new animal-related projects, so keep an eye out! Thanks again for four awesome years!