Stranger than Fiction: The evolution of the horse

Did you know that the horse used to be the size of a small dog and is native to North America?

Even though the horse is native, horses in North America are considered feral, not truly wild, because they were brought here by European settlers.

The earliest ancestor of the horse appeared around 55 million years ago and was the size of a small dog or large cat. Rather than hooves, it had multiple toes: four on its front feet and three on its back feet. These ancient horses browsed in the forest, and migrated all over North America, Siberia, Asia and Europe. They were prey for many of the larger predators and birds, but had spots and stripes that worked as camouflage in the forest.

The Mesohippus and Miohippus appeared around 30 million years ago. These horses were larger than previous ancestors and now had three toes on all of their feet. As the climate had changed, they became grazers and were able to survive on grassy plains. Many of these horses lived on the plains of Colorado and Wyoming.

By 14 million years ago, the Parahippus was living in North America. The size of large dogs, they were starting to develop normal horse behaviors and lived in bands, with a lead mare and stallion protecting the herd.

Ten million years ago, horse ancestors were pony-sized and still lived in North America. These prairie dwellers relied on speed to escape predators. The first one-toed horse appeared at about this time and started developing longer legs.

These horses continued to evolve, and eventually only a few species of the family Equus survived. Until about 12,000 years ago, the horse was living in North America. It died off with the other mega-fauna such as the woolly mammoth. The remaining species of Equus - Zebras, Donkeys and horses (Equus Caballus) - still were living in Africa, Asia, and Europe.

Humans had been hunting these species of horses for food for more than 30,000 years. Horses, however, were not domesticated or used for riding or driving until about 5,600 years ago. Horses were reintroduced to North America by Christopher Columbus during his second voyage to the “new world.”

The wild mustangs which now roam the western United States are ancestors of the horses brought here by the Spanish and other colonists. Horses would escape or be turned loose and eventually formed the herds we see today.

These horses also have no natural predators in North America, so it is up to us to control the damage they do to the environment - because we reintroduced them to the continent.

Wild Horses - and a Government Program that Works

A roundup of wild horses took place about a week ago near Durango, Colo. These roundups, which occur annually all across the western United States, are part of the Bureau of Land Management's strategy as part of the Wild Free-Roaming Horses and Burros Act of 1971. The act charged the BLM with managing the West's wild horses to maintain herd and resource health.

Recently, many people have charged that the BLM is not doing its job, and actually harming the horses by removing them from the wild. Protests and lawsuits are common at wild-horse roundups. These people believe that wild horses are endangered, and that removing and stressing them could cause them to stop breeding, leading to the disappearance of wild herds.

That impression is false.

Horses compete with all other range animals -- deer, elk and domestic grazing stock such as cows and sheep -- for resource use. Any area can support only a limited number of animals, depending on the quality and amount of forage that grows there. In the arid western United States, rangeland forage can be very sparse, meaning that sustainable herd size is fairly small.

The estimated carrying capacity of the western range for wild horses is about 26,000 - but almost 40,000 horses and burros roam the West's public land today. Thus, wild horse populations are too large to be sustainable. Because horse herds can double in size every four years, a significant number of horses must be removed every year.

Wild horses have no natural predators and are not native to North America. The only ways to control herd size are to remove horses from the range and control reproduction. The roundups give the BLM the opportunity to do both.

Federal land managers are starting a program to give mares hormone shots to prevent pregnancy, which eventually will reduce the need for roundups and keep herd levels more sustainable. The horses the BLM removes from the range are either adopted or sent to pastures in the Midwest where they live out their lives. About 41,000 wild horses are kept in these pastures today.

The American mustang is not endangered in any way. The Wild Horse and Burro Act was a directive to preserve the mustang in a sustainable way on public lands.

While I fully support monitoring government agencies and holding them accountable, protests without full information are pointless and degrade the cause.

For more information on the Wild Horse and Burro Program, check out the BLM’s website: http://www.blm.gov/wo/st/en/prog/whbprogram/history_and_facts/quick_facts.html

http://www.blm.gov/wo/st/en/prog/whbprogram/history_and_facts/myths_and_facts.html