Facing wild-horse realities in a thoughtful, humane manner requires an informed approach to the management of wild horses based on science, experience, and yes, creativity and imagination.

First, the science. Wild horses are a reintroduced species native to North America, as evidenced by fossil records dating back 1.4 million years. Molecular biology using mitochondrial DNA analysis of fossils proves that modern wild horses here in the West are the same species as the first horses in North America. No evidence exists for the origin of the horse other than in North America.

Those of us who have spent time in the wild with wild horses, including the authors of this commentary, know that horses do not "tromp down stream beds." As a prey animal, horses are vulnerable when watering and so they leave water sources when finished drinking. This is in contrast to stagnant grazers, such as livestock, that remain in the same area over long periods of time.

As for the myth that horses' hooves cause more damage than the hooves of cows — on what research is this based? Uncontrolled livestock grazing contributes to degradation of the land, as do many other phenomena, — mining, logging, wildlife and humans. As for claims of widespread environmental damage attributed to wild horses, the numbers don't add up. Thirty thousand wild horses share public lands in 10 Western states with many other wildlife species and millions of privately owned livestock. The sheer number of livestock means they have far more potential impact on grazing, water sources and habitat. A better balance of native wildlife and livestock has the potential for a far greater positive impact on the environment.

Where science, experience, creativity and imagination connect is with Porcine Zona Pellucida, or PZP, an immunocontraceptive in existence since 1972. Twenty years of data and successful management of some wild-horse herds have proven its effectiveness, and long-acting versions of PZP are being tested. This is in sharp contrast to more than 100 years of efforts to poison, shoot and otherwise eradicate wild horses in the West, which has often served to push them further into remote lands where they continue to survive and reproduce. PZP addresses the key issue of wild horse reproduction and provides a humane means to manage wild-horse herds in sustainable numbers.

In a unique, public, nonprofit, and private partnership between the U.S. Forest Service, Sky Mountain Wild Horse Sanctuary, and Mount Taylor Mustangs, with funding from Thaw Charitable Trust and Messengers of the Healing Winds Foundation, wild horses are being treated with PZP in the rugged 74,000 acre Jicarilla Wild Horse Territory of the Carson National Forest. The first-of-its kind project on Forest Service lands uses remote treatment of wild horses with small darts as they roam in the territory; no helicopters, corrals, or holding chutes are necessary.

We cannot kill our way out of this challenge, History and past efforts at 'management' through shooting horses have shown us that. It is the ultimate in a failure of imagination and humanity. We can do better using science and innovation, and we are, right here in the Carson.

Karen Herman, Ph.D. is president of the Sky Mountain Wild Horse Sanctuary in Santa Fe. Jay F. Kirkpatrick, Ph.D., is director of The Science and Conservation Center, Billings, Mont.