Evolution Of The Horse

Horse Evolution
The modern day horse of today is the result of over 55 million years of evolution. The fossilised remains of Eohippus who is also known as the 'Dawn Horse' or 'Hyracotherium', is considered to be where the horse, or 'Equus', as we know them today, originated from. Eohippus not only developed into Equus, but it also led to a whole family tree of other equine species.

Eohippus

Name
Means 'Dawn Horse'
Area Found
North America
Historical Period
Eocene Period around 50 to 55 million years ago
Height
Eohippus was the size of a small dog at around 14 inches or 3.2HH.
Diet
The diet of Eohippus was largely foliage, fruit, herbs and berries.
Conformation
- Forefeet had pads similar to those found on a dog and not hooves.
- Four toes on the front feet.
- Hind feet had pads similar to those found on dogs on their feet.
- Three toes on the hind feet.
- Short neck.
- The back was raised in a slight arch.
- Teeth - Eohippus had three incisors, one canine, four pre molars and three grinding molars on each side of the jaw.
Eohippus Sub Species
Eohippus branched off into three sub species:
- Orohippus
  Orohippus continued to evolve.
- Propalaeotherium
  Propalaeotherium evolved into Paleotherium and then evolved no further.
- Pachynolophus
  Pachynolophus evolved no further.

Orohippus

Name
Means 'Mountain Horse'
Area Found
North America
Pre-History Period
Mid Eocene Period around 40 to 50 million years ago.
Height
Orohippus was around 10 to 14 inches high or 3.2HH.
Diet
Berries, fruit and more varied foliage.
Conformation
- Forefeet had pads and four toes.
- Hind feet had three toes and pads.
- Orohippus had a short neck
- The back was arched.
- Teeth o Three incisors, one canine, four pre molars and three molars, starting to change to give greater chewing and grinding action.
Orohippus Sub Species
- Haplohippus
  Haplohippus developed no further
- Epihippus
  Epihippus continued on.

Epihippus

Area Found
North America
Period
Mid Eocene around 47 million years ago.
Height
10 to 14 inches high or 3.2HH.
Diet
Berries, fruit and foliage.
Conformation
- Forefeet had pads and four toes.
- Hind feet had pads and three toes.
- Short length of neck.
- Back was arched.
Teeth
Three incisors, one canine, two pre molars, five molars.
Evolution
Epihippus evolved into Mesohippus.

Mesohippus

Name
Means 'Middle Horse'
Pre-History Period
Oligocene Period around 40 to 20 million years ago.
Height
Twenty four inches high or 6 HH.
Diet
Varied foliage.
Conformation
- Forelegs increasing in length.
- Hind feet increasing in length.
- Three toes on the front feet.
- Three toes on the hind feet.
- Neck was longer.
- Back was not as arched as with Epihippus.
Teeth
Three incisors and six molar teeth on each side.
Evolution
Mesohippus evolved into Miohippus.

Miohippus

Name
Means 'Small Horse'.
Period
Oligocene Era around 36 to 34 million years ago.
Height
30 inches high.
Diet
Miohippus could tackle tougher forage.
Conformation
- Forefeet long legs
- Hind feet long legs o Three toes on the front and hind legs.
- Neck long in length
- Back longer with less upward arching.
Teeth
The molars developed more of a crest enabling Miohipus to tackle tougher grazing.
Sub Species Evolution
Miohippus evolved into three sub species:
- Archeohippus
  Archeohippus evolved no further.
- Anchitherium
  Anchitherium evolved into Hypohippus, Megahippus and Sinohippus.
- Parahippus
  Parahippus continued and quickly evolved into Merrychippus.

Merrychippus

Name
Means 'Ruminant Horse'
Period
Miocene Period around 20 to 11 million years ago.
Area
North America
Height
Around 42 to 48 inches high or 10.2 to 12 HH.
Conformation
- Front legs o Able to stand on one central toe with the side toes still partly functioning and the forelegs much longer than before.
- Hind legs able to stand on one toe still with the side toes still partly functioning. Hind legs becoming much longer.
- Neck increasing in length.
- Body becoming heavier and more powerful to enable them to flee from any predators.
Diet
Moved more onto the open plains for their diet.
Sub Species Evolution
Calppus, Pliohippus and Pseudohipparion:
- Calippus
  Calippus evolved no further.
- Pliohippus
  Pliohippus continued to evolve.
- Pseudhipparion
  Pseudhipparion evolved no further.

Pliohippus

Name
Means 'More Horse'
Period
Mid Miocene Period around 5 to 11 million years ago.
Area
North and South America as well as in Asia, Africa and Europe.
Height
Around 51 inches or 12.3 HH
Conformation
- Front and hind legs: one single toe that becomes the hoof. The side toes have now formed into splint bones on either side of the cannon bone and the pads have developed into the frog on the sole of the hoof.
- Body strong and solid, looking much like the horse we know today.
- Neck strong and more slender allowing Pliohippus to balance and easily reach for forage.
Diet
Grazing on the plains

Dinohippus

Name
Means 'Powerful Horse'.
Period
Pliocene Era around 13 to 5 million years ago.
Height
51 inches or 12.3 HH.
Conformation
- Forelimbs are strong with the single toe now a hoof.

Hind limbs are strong and powerful with the single toe now a hoof.
Body has become sturdy and powerful
Neck has become powerful and more muscular.

Diet
Grazing on grasses on the plains.

Equus

Name
Means 'Horse'.
Period
Pleistocene Period 10 to 2 million years ago.
Height
52 inches or 13HH
Conformation
- Front legs long and strong giving the horse speed and athleticism
- Hind legs muscular and strong giving the horse great power, speed and endurance.
- Body compact and strong
- Neck muscular and strong allowing Equus to balance and easily reach for forage.
Diet
Mainly grass and herbs