Log in Page Discussion History Go to the site toolbox

Horses

From BluWiki

The Przewalski's horse is the last true wild horse. All other horses are domestic or feral.

The horse (Equus caballus) is a species of perissodactyl, or odd-toed ungulate. It along with 9 other species of equines, such as donkeys and asses, is included in the genus Equus. Horses were originally found on the steppes of Poland to Mongolia but have now spread across the world thanks to their domestication. Feral horses can survive in a variety of habitats including forest, grassland, and desert. Horses range anywhere from 300 to 2000 kilos (or rather 660 to 4400 pounds). There are many different varieties of horse ranging from the largest breed, the Shire horse, which can be over 180 centimeters tall, to the smallest, the Falabella horse, which is about 75 centimeters tall at maturity. Generally, horses have long limbs, barrel shaped bodies, and long necks. The tail is short but has long hairs for swatting flies and other insects. Horses are also known for their long manes and forelocks. Horses typically have only one foal, after having gone through a gestation period of about 11 months. Soon after birth, the foal can follow its mother around (usually about 15 to 25 minutes). Horses live in patriarchal herds in which one male lives with several females and their offspring. Lone males form bachelor herds. They graze which means that most of their diet consists of grass.

Horse Evolution

This is an illustration of Hyracotherium.

For more detailed information, view the [Wikipedia article]

The evolution of the modern horse began with the fox-sized Hyracotherium 54 million years ago. Hyracotherium, unlike modern horses, spent its time in the forest foraging for leaves and fruit. In behavior it probably resembled the muntjac (a group of highly primitive deer species). Hyracotherium had many primitive features including four toes instead of one in modern horses. About 50 million years ago, Hyracotherium evolved into Orohippus. Orohippus had teeth better devloped for grinding tougher food items and had a slimmer body, elongated head, and longer legs (more typical of a jumper). Later at about 40 million years ago, grasslands began to become much more common so horses changed with their environment. Mesohippus was larger and taller than its predecessors and was well adept for running and evading predators in open, non-wooded areas. It walked on three toes rather than four and was much more agile. Miohippus came about 36 million years ago. It was becoming much more horse like in the areas of dentition and anatomy. Miohippus is important because began a new period in equid diversification, its ancestors split into two groups: equids that returned to the forest and those that adapted to the prairies.

The species that returned to the forest became Kalobatihippus. Kalobatihippus (also classified as Miohippus intermedius) had feet developed for walking on the soft forest floor. It crossed the Bering land bridge into Asia and then into Europe where it evolved into Hypohippus.

Parahippus is believed to be descended from the Miohippids that remained on the prairie. Its teeth are highly developed for chewing tough plant material such as grasses. What is important about Parahippus is that it can walk on its middle toe without having to walk on toe pads. It was about the size of a small pony. After Parahippus came Merychippus which had teeth even better developed for the grasses of the steppes. Merychippus is believed to be the common ancestor of three new equids: Hipparion, Protohippus, and Pliohippus. Hipparion was the most different from its ancestor and had a slim body like an antelope and was developed for life on dry prairies. Plesippus is the ancestor of the genus Equus. Near the end of the Pliocene, the climate began to cool so several groups of this species migrated. One group moved south to South America where it evolved into Hippidion, another group moved to Eurasia, and the last group remained in southern North America.

The tarpan (Equus ferus ferus) is a species of wild horse.

The first true horse was Equus stenonis of Italy. It moved to North America where it evolved into species such as Equus scotti. These North American horses went extinct at the end of the most recent ice age 11,000 years ago. In an ironic way, horses evolved in North America but would no longer naturally exist there. The modern horse Equus caballus evolved from a wild ancestor known as Equus ferus. The horse line is believed to have split from the zebra/donkey line 4 to 2 million years ago.

Domestication

Horses are currently believed to have been first domesticated in Ukraine about 4000 BC but other estimates reach as far back as 8000 BC. It is unknown which subspecies of Equus ferus specifically gave rise to the domestic horse. Genetic evidence suggest that horses were domesticated in many places at many times.

The Future of Horses

Could this be what horses look like in 50 million years?

What sorts of species of horse might exist in the future? Before there could even be any future horses, then horses must first survive long enough to evolve. Horses easily adapt to their environments, revert to a feral state quickly, and are relatively good at maintaining themselves. As such advanced species though they will be highly limited in sorts of species they might evolve into. The gazelle like and llama like horses in the picture to the right are not very accurate as they would need a complete revision of the horse's anatomy. The indricothere-type horse is not so bad though as the horse has the features that could develop in that direction. The only problem would be the horse's legs. A horse is developed for running on wide prairies and is not too well adept for a very large body weight.

If horses disappear, what animals might take their place? Any number of different herbivores could become possibly horse-like. First would be the asses or donkeys which already have the same basic form as a horse. Smaller grazers such as antelope or deer might also become horse-like through in increase in size. Other possible candidates include swine (hogs, boars, warthogs, and peccaries) and hyraxes (small animals closed related elephants and manatees).

If there is a mass extinction, where might horses survive? The places where horses will most likely survive will be isolated areas where competition is limited. Thus islands are a good candidate. Places such as Hawaii or Australia where horses and ponies might survive as feral populations would allow the new horse species to develop without much trouble from other large herbivores. In Australia, the horses would only have to compete with camels (who are also introduced) and the native marsupials (which are much more primitive than the placental horses). In Hawaii there are no other large herbivores that could compete with horses in any way. In such isolated environments, you must remember that the horses would likely dwarf in size (as in elephants and mammoths in the Mediterranean and some Alaskan and Californian islands).

Site Toolbox:

Personal tools
GNU Free Documentation License 1.2
This page was last modified on 29 September 2007, at 23:33.
Disclaimers - About BluWiki