The coexistence of humans and animals is very interesting and amazing. It is amazing that different creatures and species are coexisting harmoniously. This can be traced back to the ancient civilization wherein most of the complex things we have these days originated in those times. Sometimes we may wonder how the presence of life and all things which have life were then and now. But one fact remains that both have been very useful to one another even before. People in the ancient times have used animals for their benefit while animals benefit from humans by being taken care of. However, the animals and even people now have significant developments in their physical appearance. Over the years, humans and animals alike have evolved into probably better versions of themselves.
As civilization has been mentioned, it is inevitable not to come across one predominant animal which has been present and has been beneficial to human history. This animal is the horse. This animal has been a great help to people in their daily lives and has contributed a lot to history. If you have noticed in movies which are set in old periods, there would always be horses involved in filming. They have been the means of transportation and paraphernalia of war in the ancient times.
It is very interesting how could have horses evolved over time. For experts, the fact that horses have been widely used by people for various purposes led them into studying the evolution of horse from prehistory.
Since prehistory wild horses were known to be roaming around the plains of Central Asia to Europe while the domestic horses have been widely spread in the Old World. But, no other types of horses were found in the New World when European explorers reached the Americas. In the beginning of 1493 when Spanish colonists brought with them domestic horses from Europe, these horses were quick to establish large herds. Horses are deeply entrenched in the North American society. As it has penetrated in the North American plains, it has transformed and has impacted agriculture and the transportation system. According to study, the North American prehistoric horse has evolved multiple times in a period of 50 million years. Also, experts found out in their research that original form of horses is similar to a small dog.
PREHISTORIC HORSES PERIOD
The evolution of horses can be divided into three periods namely the Eocene and Oligocene period, the Miocene and Pliocene period and lastly the Modern day horses. Every period has its own unique characteristics which differentiate horses from another period.
- EOCENE AND OLIGOCENE
As mentioned, over the years and throughout the stages of evolution, modern day horses have gone through a lot of changes. During this period, there were a number of animals associated with the evolution of the horse such as Eohippus, Orohippus, Epihippus, Mesohippus, Miohippus.
Eohippus is a dog like horse that lived in the early Eocene era and has a very small and distinct three toes. This animal over time has evolved into Orohippus. Although it evolved from what is considered as an origin of the horse, Orohippus is not considered as a true horse. It has four toes on each of the front leg and three toes on the hind legs.
The Orohippus have also evolved into another creature called Epihippus after some million years after. Like any other previous species of horses, Epihippus has also had to develop a tooth for grinding. One of the premises in the theory of evolution stated that animals have the ability to adapt and develop something according to the environment they are in. Likewise, Epihippus is thought to have developed a grinding a teeth due to its exposure to plains which allows it to graze around and was only 2 feet tall.
As the climate and the environment in North America changed, the living creatures also adapted to the changes around. Their physical appearance and abilities have also developed such as the Epihippus evolved to become Mesohippus. This horse is perceived to have developed tougher grinding teeth, larger in size and longer and stronger legs. Mesohippus has three toes on every front and hind feet. Then sometime after Miohippus evolved from Mesohippus. This horse is larger than the Mesohippus and it has larger and deeper facial features. Also, it shows evidence of a horse’s teeth which is having an extra crest in the upper cheek. Miohippus continued to survive until the Miocene period when it began to diversify itself which then branched out into two groups.
- MIOCENE AND PLIOCENE PERIOD
After Eocene and Oligocene period came to the Miocene and Pliocene which was considered as a period of true horses or equines.
In this period lived the animal called Kalobatippus. The physique it possesses is apt for forest environment wherein it has four toes in the front in which the second and were long enough to suit traveling in the forest. Another animal which emerged during this period was called Parahippus who was believed to have evolved from the remnants of Miohippus whose size was similar to a pony. It has similar facial features with the horses today.
Sometime in the mid-Miocene period, another animal emerged which was called Merychippus. This animal had developed wider molars which were used for munching hard grasses on the plains. Its legs were quite short and have toes which have small hooves. Also, it is considered to be the most successful prehistoric horse specie as it has generated at least 19 more grassland species.
The other prehistoric horses namely Hipparion and Pliohippus are believed to have descended from Merychippus. The former was considered as a successful breed by paleontologists. Hipparion’s physique shows that it is well-adapted living on plains. The legs were slim and have a slim body size somewhat like a small pony. On the other hand, Pliohippus is believed to be closely related to the modern day horses due to the similarities in their anatomy. However, compared to the modern day horse, Pliohippus have strongly curved teeth and have a deep facial feature.
In the late Pliocene period, the common species of Equidae, particularly in North America, is the Dinohippus. Then, Plesippus emerged which was considered as a mid-stage of Dinohippus and Equus.
- MODERN DAY HORSE
The modern day horse which is also scientifically called as Equus has evolved from Dinohippus through Plesippus. The oldest fossil of this breed which is about 3.5 million years old is found in Idaho, USA which belongs to the oldest species called Equus simplicidens. It is similar to a zebra that has a head shaped like a donkey.
Dinohippus which is the ancestor of Equus weighs around 750 pounds and is 5 feet tall. The ability of Dinohippus to stand for long periods associate it with the Equus as it also possesses the same ability. The success of Equus is evidenced in its widespread in the Old World. It was also believed that it has reached Eurasia.
However, the horses, in general, have become extinct in North America at one point in the past. The cause of the extinction has been under debate among experts. There are three reasons for extinction which are debated by paleontologists such climate change, overexploitation of newly arrived humans, and the other one is the age. The survival of this species has become possible with those who have migrated to other territories. It was only in the 15th and 16th centuries that horses were brought back to America. It was through Christopher Columbus that horses were able to set foot again on America.
After its return to America, horses have greatly impacted and influenced the lifestyle of the American society. Horses used to have a small body that resembles a dog but now they could weigh up to 1500 pounds and has a sturdy body built which allows them to play a part in the American agriculture. In addition, horses have played and are continuously taking significant roles in the human history.