A Horse is a Horse, Of Course?

Repost from: LinkedIn


No, this isn’t an article about how Mister Ed was really a Zebra*. It is actually about the evolution of horses.

To anyone confused about the reality of evolution, horse evolution is one that’s pretty easy to follow. The fossil record of horses is one of the most complete records we have showing the gradual evolution of these wonderful creatures.

Anti-evolutionists tend to argue that horses are still horses, that “there is no evidence of transitional species”. Well, let’s take a look. Look at the figures below:

Hyracotherium (55 mya)

AKA Eohippus. If this creature were alive today, it would not look like a horse at all. In fact, it would look more like a big-headed, thick-necked dog. Its eyes were mid-way down the face and not high up on the head like modern horses. The fossil record and radiometric dating show this horse is much older than horses that followed, showing that they lived long before Mr. Ed.

See its toes below:

The legs and teeth between species went through gradual changes. Notice how Merychippus’s bones are fusing. Early horses didn’t have hooves. They had multiple toes that we clearly see merging as we move up the fossil record.

Click the Link to see: – Horse Teeth and Legs

Orohippus (52-45 mya)

This horse ancestor arrived on the scene while his Hyracotherium cousins were still around, but they were more wide-spread. The differences are slight but Orohippus has a longer head and slimmer body. Toes were essentially the same. Fossils of Orohippus have been found in Eocene sediments in Wyoming and Oregon.

DID YOU KNOW? – Horses and Zebras have more genetic differentiation between them than Humans and Chimpanzees? Yet, hardly no one denies that Zebras and Horses are related and share a common ancestor.

Mesohippus (37 to 32 mya)

Mesohippus is the “middle horse”, so named because this horse is considered an obvious transitional form between the early horses and Equus. Like many horses, it was common in North America. This horse still did not have what we view as a modern hoof. This horse had lost one of its toes but the other’s appear to offer some support but most of its weight rested on its large central toe. The eyes were further back on the head and the eyes were rounder than previous species.

Miohippus (32 – 25 mya)

This Oligocene horse was also a tree-toed horse. Much larger and more wide-spread than its ancestors, it spread all over the North American continent. It’s considered a very successful species spanning over 10 million years, and is considered to be an ancestral horse responsible a great diversity of horse species.

Parahippus (24 – 17 mya)

Parahippus is considered an evolutionary link between forest dwelling horses and horses of the plains. They also had three toes but the side toes were greatly reduced. Parahippus was larger than Miohippus and had a face that many would associate with a horse.

Merychippus (17 – 11 mya)

Merychippus, a term that I will probably use during the Christmas Holy Days from now on, is a proto-horse that was endemic to North America. It is considered the first grazing horse and had many features like a modern horse. Teeth and Toes were not like modern horses however.

Pliohippus (12 – 6 mya)

Pliohippus lived in the middle Miocene and had two stubs near the sides of its hoof. It’s believed to be the direct ancestor of modern horses. In fact, if you saw it today, you wouldn’t really notice the differences at first. Its teeth were curved instead of straight like modern horses. If the Trojan Horse had a Skeleton, it would look like this guy. This horse was buff! 🙂

Dinohippus (13 -5 mya)

This “terrible horse” was the most common horse in North America and believed to be the closest relative of Mr. Ed. “It possesses a distinctive passive “stay apparatus,” formed by bones and tendons, to help it conserve energy while standing for long periods. Dinohippus is the first horse to show a rudimentary form of this character, providing additional evidence of the close relationship between Dinohippus and Equus.” – Reposted from the Florida Museum of Natural History

Equus (5 mya – Present)

Equus (Mr. Ed.) is the only surviving genus of the horse family. It’s a new comer within the evolution of horses; but then again, like all organisms on our planet, horse populations are in constant transition. The Equidae family of horses will probably look even different still 10 million years from now. Extant (existing) species include the zebras, horses, and asses. Fossils of Equus are found on every continent except Australia and Antarctica.

Some have argued that horses could not have evolved because horse fossils have been found all over the Earth. Not quite, as shown above. But yes, there are fossils found in many different areas and in distinct environments; but what age are the fossils and does their distribution match plausible migratory paths via the fossil record and paleogeology? Yes! They do. To argue that fossil distribution goes against evolution is akin to saying that humans couldn’t have evolved because humans are all over the Earth.

Another attempted refutation against equine evolution is that each of these creatures were created complete and in tact via magic, and they just popped into existence. This isn’t a scientific statement and can be safely ignored; however, if one wishes, it can be analyzed Socratically. One could ask, “Why do we see gradual differences (over time) between species 55 mya till today?” Some have argued that the creator was experimenting; but if true, doesn’t this allude to the creator having a lack of knowledge? Of course if aliens created horses, that’s far more plausible. 🙂

I concede my bias. I do have a scientific mind, so I think evolution via natural selection explains horse evolution just fine. Could I be wrong? Yes, I could. This is why science rocks: Evidence is what counts, not what I believe in.

* No, Mr. Ed wasn’t a Zebra despite some websites stating otherwise.


Florida Museum of Natural History

Horse Evolution Over 55 Million Years


Quick References:

Wikipedia.orgPlease reference the references for any Wikipedia Entry

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