The evolution of the horse pertains to the phylogenetic ancestry of the modern horse from the small, dog-sized, forest-dwelling Eohippus over geologic time scales. Paleozoologists have been able to piece together a more complete picture of the modern horse's evolutionary lineage than that of any other animal.
The horse belongs to an order known as Perissodactyla, or "odd-toed ungulates", which all share hooved feet and an odd number of toes on each foot, as well as mobile upper lips and a similar tooth structure. This means that horses share a common ancestry with tapirs and rhinoceroses. The perissodactyls arose in the late Paleocene, less than 10 million years after the Cretaceous–Paleogene extinction event. This group of animals appears to have been originally specialized for life in tropical forests, but whereas tapirs and, to some extent, rhinoceroses, retained their jungle specializations, modern horses are adapted to life on drier land, in the much-harsher climatic conditions of the steppes. Other species of Equus are adapted to a variety of intermediate conditions.
The early ancestors of the modern horse walked on several spread-out toes, an accommodation to life spent walking on the soft, moist grounds of primeval forests. As grass species began to appear and flourish, the equids' diets shifted from foliage to grasses, leading to larger and more durable teeth. At the same time, as the steppes began to appear, the horse's predecessors needed to be capable of greater speeds to outrun predators. This was attained through the lengthening of limbs and the lifting of some toes from the ground in such a way that the weight of the body was gradually placed on one of the longest toes, the third.
Other articles related to "evolution of the horse, of the horse, the horse, evolution, horse, horses":
... Throughout the phylogenetic development, the teeth of the horse underwent significant changes ... In conjunction with the teeth, during the horse’s evolution, the elongation of the facial part of the skull is apparent, and can also be observed in ...
... Main article Evolution of the horse Due to an almost-complete fossil record found in North American sedimentary deposits from the early Eocene to the present, the ... show it to have differed from the modern horse in three important respects it was a small animal (the size of a fox), lightly built and adapted for running the limbs were short and slender, and the ... The probable course of development of horses from Hyracotherium to Equus (the modern horse) involved at least 12 genera and several hundred species ...
Famous quotes containing the words evolution of, horse and/or evolution:
“The evolution of humans can not only be seen as the grand total of their wars, it is also defined by the evolution of the human mind and the development of the human consciousness.”
—Friedrich Dürrenmatt (19211990)
“I on my horse, and Love on me, doth try
Our horsemanships, while by strange work I prove
A horseman to my horse, a horse to Love,”
—Sir Philip Sidney (15541586)
“Historians will have to face the fact that natural selection determined the evolution of cultures in the same manner as it did that of species.”
—Konrad Lorenz (19031989)