Horses are living with us for more than 6000 years. Due to the specific feature of body anatomy horses have great speed endurance balance that was used by humans for ages. Also, horses are capable of sleeping both standing and laying down. Currently there are more than 300 horse breeds which are divided in 3 main categories: “hot bloods” – with amazing speed and endurance, “cold bloods” – that can sustain long and heavy work, and “warm bloods” – which are crosses between hot and cold categories.
The evolution of horses is well documented fossils that show how small the size of a dog, forestry, animal Propalaeotherium possessing fingers instead of hooves, for 50 million years, has become a large ungulates inhabitants of open spaces. Main speciation occurred within North America, where existed at Natural Bridge is their penetration into Eurasia, where possible, in the absence of the Bering Strait and to the formation of a powerful ice sheet.
The evolution of horses began in the Eocene, about 55 million years ago. While there Hyracotherium – ancestor of all current horses, a small mammal with a height at the shoulders is 20 cm, the small teeth to chew its leaves and fruit. Hyracotherium does not resemble today’s horses. This animal was arched back, short neck and muzzle, short legs and a long tail. It was a stocky creature the size of a fox, with a four-toed limbs. Skull and brain volume was relatively small.
About 50 million years ago from the genus Hyracotherium stood Orohippus (Orohippus). First of all, changed limbs and teeth, Orohippus preferred a more solid vegetarian food. Three million years later Orohippus evolved into a new genus Epihippus (epigippus). Meanwhile, the climate has changed significantly in North America became drier forests declined, giving way to open savannah. This was a key event in the evolution of horses, as they were forced to adapt to new conditions. They became larger, allowing them to move quickly and completely switched to herbal food.
40 million years ago formed a kind of Mesohippus (Mesohippus). Height at the withers of the horse was about 60 cm, the back was no longer curved, as her ancestors, and legs, neck and face became longer. Also changed the structure of its hooves. About 35 million years ago, he moved to the genus Miohippus, whose members became even more, and their faces were extended further.
23 million years ago, a race Parahippus. This beast was more adapted teeth and only three have hooves finger. Parahippus descendants became members of the genus Merychippus (Merychippus) at the withers reaches up to one meter. Their skull is already resembled a skull modern horses, and the volume of the brain increased significantly. Rhode Merychippus (Merychippus) divided into several evolutionary lines, some of which are extinct. After an intermediary called Dinohippus about 1.5 million years ago there were modern horse genus Equus caballus.
In North America, the horse became extinct thousands of years ago, before during European colonization in the XVI century there were again brought representatives of the types of domestic horses and a donkey. Feral populations vvezёnnyh horses became known as mustangs. A similar process took place in Australia, which had never been members of the genus horses.