Prehistoric Horse Pictures and Profiles

01
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Meet the Prehistoric Horses of Cenozoic North America

equus
Wikimedia Commons

Modern horses have come a long way since their prehistoric ancestors roamed the grasslands and prairies of Cenozoic North America. On the following slides, you'll find pictures and detailed profiles of over a dozen prehistoric horses, ranging from the American Zebra to the Tarpan.

02
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American Zebra

American Zebra
American Zebra. Hagerman Fossil Beds National Monument

Name:

American Zebra; also known as the Hagerman horse and Equus simplicidens

Habitat:

Plains of North America

Historical Epoch:

Pliocene (5-2 million years ago)

Size and Weight:

About 4-5 feet tall and 500-1,000 pounds

Diet:

Grass

Distinguishing Characteristics:

Stocky build; narrow skull; probably stripes

When its remains were first unearthed, in 1928, the American Zebra was identified as a new genus of prehistoric horse, Plesippus. On further examination, though, paleontologists determined that this stocky, thick-necked grazer was one of the earliest species of Equus, the genus that comprises modern horses, zebras and donkeys, and was most closely related to the still extant Grevy's Zebra of eastern Africa. Also known as the Hagerman horse (after the town in Idaho where it was discovered), Equus simplicidens may or may not have sported zebra-like stripes, and if so, they were probably restricted to limited portions of its body.

Notably, this early horse is represented in the fossil record by no less than five complete skeletons and a hundred skulls, the remnants of a herd that drowned in a flash flood about three million years ago. (See a slideshow of 10 Recently Extinct Horses.)

03
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Anchitherium

anchitherium
Anchitherium. London Natural History Museum

Name:

Anchitherium (Greek for "near mammal"); pronounced ANN-chee-THEE-ree-um

Habitat:

Woodlands of North America and Eurasia

Historical Epoch:

Miocene (25-5 million years ago)

Size and Weight:

About three feet tall and a few hundred pounds

Diet:

Plants

Distinguishing Characteristics:

Small size; three-toed feet

As successful as Anchitherium was--this prehistoric horse persisted throughout the entire Miocene epoch, or close to 20 million years--the fact is that it represented a mere side branch in equine evolution, and wasn't directly ancestral to modern horses, genus Equus. In fact, around 15 million years ago, Anchitherium was displaced from its North American habitat by better-adapted equines like Hipparion and Merychippus, which forced it migrate to the less-populous woodlands of Europe and Asia.

04
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Dinohippus

dinohippus
Dinohippus. Eduardo Camarga

Name:

Dinohippus (Greek for "terrible horse"); pronounced DIE-no-HIP-us

Habitat:

Plains of North America

Historical Epoch:

Late Miocene (13-5 million years ago)

Size and Weight:

About five feet tall and 750 pounds

Diet:

Plants

Distinguishing Characteristics:

One- and three-toed feet; ability to stand for long periods of time

Despite its dinosaur-worthy name (Greek for "terrible horse"), you might be disappointed to learn that Dinohippus wasn't especially big or dangerous--in fact, this prehistoric horse (which was once considered to be a species of Pliohippus) is now thought to have been the immediate precursor of the modern genus Equus. The giveaway is Dinohippus' primitive "stay apparatus"--a telltale arrangement of the bones and tendons in its legs that allowed it to stand for long periods of time, like modern horses. There are three named Dinohippus species: D. interpolatus, once classified as a species of the now-discarded Hippidium; D. mexicanus, once classified as a species of donkey; and D. spectans, which spent a few years under yet another prehistoric horse genus, Protohippus.

05
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Epihippus

epihippus
Epihippus. Florida Museum of Natural History

Name:

Epihippus (Greek for "marginal horse"); pronounced EPP-ee-HIP-us

Habitat:

Plains of North America

Historical Epoch:

Late Eocene (30 million years ago)

Size and Weight:

About two feet high and a few hundred pounds

Diet:

Plants

Distinguishing Characteristics:

Small size; four-toed front feet

As prehistoric horses go, Epihippus represented a slight evolutionary advance over its immediate predecessor, Orohippus. This small equine had ten, rather than six, grinding teeth in its jaws, and the middle toes of its front and hind feet were slightly bigger and stronger (anticipating the single, huge toes of modern horses). Also, Epihippus appears to have thrived in the meadows of the late Eocene epoch, rather than the forests and woodlands inhabited by the other prehistoric horses of its day.

06
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Eurohippus

eurohippus
Eurohippus. Wikimedia Commons

Name

Eurohippus (Greek for "European horse"); pronounced YOUR-oh-HIP-uss

Habitat

Plains of western Europe

Historical Period

Middle Eocene (47 million years ago)

Size and Weight

About three feet long and 20 pounds

Diet

Grass

Distinguishing Characteristics

Small size; four-toed front feet

You may be under the mistaken impression that ancestral horses were restricted to North America, but the fact is that a few ancient genera prowled Eocene Europe. Eurohippus has been known to paleontologists for years, but this dog-sized perissodactyl (odd-toed ungulate) thrust itself into the headlines when a pregnant specimen was discovered in Germany, in 2010. By studying the well-preserved fossil with X-rays, scientists have determined that the reproductive equipment of Eurohippus was extremely similar to that of modern horses (genus Equus), even though this 20-pound mammal lived nearly 50 million years ago. The mother horse, and her developing fetus, were likely felled by noxious gases from a nearby volcano.

07
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Hipparion

hipparion
Hipparion. Wikimedia Commons

Name:

Hipparion (Greek for "like a horse"); pronounced hip-AH-ree-on

Habitat:

Plains of North America, Africa and Eurasia

Historical Epoch:

Miocene-Pleistocene (20-2 million years ago)

Size and Weight:

About six feet long and 500 pounds

Diet:

Plants

Distinguishing Characteristics:

Horse-like appearance; two side toes on each foot

Along with Hippidion and Merychippus, Hipparion was one of the most successful prehistoric horses of the Miocene epoch, evolving in North America about 20 million years ago and spreading as far afield as Africa and eastern Asia. To the untrained eye, Hipparion would have appeared almost identical to the modern horse (genus name Equus), with the exception of the two vestigial toes surrounding the single hooves on each of its feet. Judging from its preserved footprints, Hipparion probably ran much like a modern thoroughbred, though it likely wasn't quite as fast.

08
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Hippidion

hippidion
Hippidion (Wikimedia Commons).

Name:

Hippidion (Greek for "like a pony"); pronounced hip-ID-ee-on

Habitat:

Plains of South America

Historical Epoch:

Pleistocene-modern (2 million-10,000 years ago)

Size and Weight:

About six feet long and 500 pounds

Diet:

Plants

Distinguishing Characteristics:

Long, prominent nasal bone on skull

Although prehistoric horses like Hipparion flourished in North America during the Eocene epoch, equines didn't make it down to South America until about two million years ago, Hippidion being the most prominent example. This ancient horse was about the size of a modern donkey, and its most distinctive feature was the prominent ridge on the front of its head that housed extra-wide nasal passages (meaning it probably had a highly developed sense of smell). Some paleontologists believe Hippidion properly belongs to the genus Equus, which would make it a kissing cousin of modern thoroughbreds.

09
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Hypohippus

hypohippus
Hypohippus. Heinrich Harder

Name:

Hypohippus (Greek for "low horse"); pronounced HI-poe-HIP-us

Habitat:

Woodlands of North America

Historical Period:

Middle Miocene (17-11 million years ago)

Size and Weight:

About six feet long and 500 pounds

Diet:

Plants

Distinguishing Characteristics:

Large size; relatively short legs with three-toed feet

You might think from its amusing name that Hypohippus ("low horse") was about the size of a mouse, but the fact is that this prehistoric horse was relatively big for Miocene North America, about the size of a modern-day pony. To judge by its relatively short legs (at least compared to other horses of the time) and spreading, three-toed feet, Hypohippus spent most of its time in the soft undergrowth of forests, rooting around for vegetation. Oddly enough, Hypohippus was named by the famous paleontologist Joseph Leidy not for its short legs (which he wasn't aware of at the time) but for the stunted profile of some of its teeth!

10
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Hyracotherium

hyracotherium
Hyracotherium. Wikimedia Commons

Hyracotherium (formerly known as Eohippus) was directly ancestral to modern-day horses, genus Equus, as well as numerous genera of prehistoric horse that roamed the plains of the Tertiary and Quaternary North America. See an in-depth profile of Hyracotherium

11
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Merychippus

merychippus
Merychippus. Wikimedia Commons

The Miocene Merychippus was the first ancestral horse to bear a noticeable resemblance to modern horses, although this genus was slightly bigger and still had vestigial toes on either side of its feet, rather than single, large hooves. See an in-depth profile of Merychippus

12
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Mesohippus

mesohippus
Mesohippus. Wikimedia Commons

Mesohippus was basically Hyracotherium advanced by a few million years, an intermediate stage between the smallish forest horses of the early Eocene epoch and the large plains browsers of the Pliocene and Pleistocene epochs. See an in-depth profile of Mesohippus

13
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Miohippus

miohippus
The skull of Miohippus. Wikimedia Commons

Although the prehistoric horse Miohippus is known by over a dozen named species, ranging from M. acutidens to M. quartus, the genus itself consisted of two basic types, one adapted to life on the open prairies and the other best suited to forests and woodlands. See an in-depth profile of Miohippus

14
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Orohippus

orohippus
Orohippus. Wikimedia Commons

Name:

Orohippus (Greek for "mountain horse"); pronounced ORE-oh-HIP-us

Habitat:

Woodlands of North America

Historical Epoch:

Early Eocene (52-45 million years ago)

Size and Weight:

About two feet high and 50 pounds

Diet:

Plants

Distinguishing Characteristics:

Small size; three-toed hind feet

One of the more obscure prehistoric horses, Orohippus lived at about the same time as Hyracotherium, the equine ancestor once known as Eohippus. The only (obvious) equine characteristics of Orohippus were the slightly enlarged middle toes on its front and hind legs; other than that, this herbivorous mammal looked more like a prehistoric deer than a modern horse. (By the way, the name Orohippus, which is Greek for "mountain horse," is a misnomer; this small mammal actually lived in level woodlands rather than high mountain peaks.)

15
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Palaeotherium

palaeotherium
Palaeotherium (Heinrich Harder).

Name:

Palaeotherium (Greek for "ancient beast"); pronounced PAH-lay-oh-THEE-ree-um

Habitat:

Woodlands of Western Europe

Historical Epoch:

Eocene-Early Oligocene (50-30 million years ago)

Size and Weight:

About four feet long and a few hundred pounds

Diet:

Plants

Distinguishing Characteristics:

Long head; possible prehensile trunk

Not all the ungulates of the Eocene and Oligocene epochs were directly ancestral to modern horses. A good example is Palaeotherium, which, even though it was related to genuine prehistoric horses like Hyracotherium (once known as Eohippus), had some distinctly tapir-like characteristics, possibly including a short, prehensile trunk on the end of its snout. Most species of Palaeotherium seem to have been fairly small, but at least one (bearing the appropriate species name "magnum") attained horse-like proportions.

16
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Parahippus

parahippus
Parahippus. Wikimedia Commons

Name:

Parahippus (Greek for "almost horse"); pronounced PAH-rah-HIP-us

Habitat:

Plains of North America

Historical Epoch:

Miocene (23-5 million years ago)

Size and Weight:

About five feet tall and 500 pounds

Diet:

Plants

Distinguishing Characteristics:

Long legs and skull; enlarged middle toes

For all intents and purposes, Parahippus was an "improved" version of another prehistoric horse, the similarly named Miohippus. Parahippus was slightly bigger than its immediate ancestor, and was built for speed on the open prairie, with relatively long legs and noticeably enlarged middle toes (on which it put most of its weight when running). The teeth of Parahippus were also well adapted to chewing and digesting the tough grass of the North American plains. Like the other "hippus"-es that it preceded and followed, Parahappus lay on the evolutionary line that led to the modern horse, genus Equus.

17
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Pliohippus

pliohippus
The skull of Pliohippus. Wikimedia Commons

Name:

Pliohippus (Greek for "Pliocene horse"); pronounced PLY-oh-HIP-us

Habitat:

Plains of North America

Historical Epoch:

Late Miocene-Pliocene (12-2 million years ago)

Size and Weight:

About six feet high and 1,000 pounds

Diet:

Plants

Distinguishing Characteristics:

Single-toed feet; depressions in skull above eyes

Like modern plains horses, Pliohippus seems to have been built for speed: this true single-toed horse roamed the grassy plains of North America between 12 million and two million years ago (the latter end of that timespan landing toward the very end of the Pliocene epoch, from which the name of this prehistoric horse derives). Although Pliohippus closely resembled modern horses, there's some debate about whether the distinctive depressions in its skull, in front of its eyes, are evidence of a parallel branch in equine evolution. Generally speaking, Pliohippus represents the next stage in horse evolution after the earlier Merychippus, although it may not have been a direct descendant.

18
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The Quagga

quagga
Quagga. public domain

DNA extracted from the hide of a preserved individual proves that the now-extinct Quagga was a sub-species of the Plains Zebra, which diverged from the parent stock in Africa sometime between 300,000 and 100,000 years ago. See an in-depth profile of the Quagga

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The Tarpan

tarpan
The Tarpan. public domain

A shaggy, ill-tempered member of the genus Equus, the Tarpan was domesticated thousands of years ago, by early Eurasian settlers, into what we now know as the modern horse--but itself went extinct in the early 20th century. See an in-depth profile of the Tarpan