Compared to mice or rats, horses might not inherently seem like great models for studying human physiology and disease. They are large, expensive to house and feed, and their bites (and kicks!) could cause a wee bit more damage than their rodent counterparts’. But horses’ size, athleticism, aging processes, and spectrum of natural diseases actually make them perfect for the role.

"The horse serves as an excellent model for studying human diseases, especially for studying metabolic disorders such as obesity," says Nicholas Frank, DVM, PhD, Dipl. ACVIM, professor and department chair of clinical sciences at Tufts University’s Cummings School of Veterinary Medicine.

Horses’ and humans’ basic body systems and physiology are quite similar, so in many cases research conducted in one species could be translated to the other. Frank notes that the list of diseases and medical conditions horses and humans have in common is rather extensive. Some examples include uveitis (inflammation of the cellular layer of the eye), cancer (e.g., melanoma), and respiratory diseases (asthma in humans, for example, resembles inflammatory airway disease in horses).

However, this does not mean horses are being used as proverbial guinea pigs. Instead, using horses as models for studying human disease more accurately falls under the canopy of "One Health," which is an international movement led by doctors and veterinarians that considers "one medicine for all." Its mission is to "promote, improve, and defend the health and well-being of all species by enhancing cooperation and collaboration between physicians, veterinarians, other scientific health and environmental professionals and by promoting strengths in leadership and management to achieve these goals," according to www.onehealthinitiative.com