Thanks to the seminal work of Robert Sapolsky, in “Why Zebras Don’t Get Ulcers,” we know have a much better understanding of the disparity between the way animals in their natural environment handle stress and the way humans do. As a result of this intensive study, we can also ascertain that both the value of identifying and responding to, the physiological triggers of alarm. And with all that being said, one would not be stretching too far to hypothesize that horses also do not get ulcers. However, nothing could be farther from the truth.
Horses, like zebras, do live in a natural environment. That is, roaming wild and fending for themselves. Yet, on the other hand, a vast number of horses do not enjoy this lifestyle. And here, we have a very interesting study. The truth is, not one case of ulcers in wild horses has been found. On the other side of the equation, racehorses, whose lifestyle is extremely demanding, exhibit ulcers in 1 out of every 5 horses at the track. Looking at the difference between the life of a wild horse, which is relatively serene, with healthy social group dynamics, and allows for freedom of response, and that of a racehorse, which is intensely demanding both physically and mentally, is lived in near complete isolation, and restricts freedom of movement, it is not hard to understand why these numbers would be so far apart. It is, indeed, a bit like comparing life in rural Colorado to downtown New York City.
But why then, do some racehorses get ulcers, and some do not? Well this phenomenon is best explained by the same principle that explains why some people suffer mental illness and others do not, when raised in similar environments. Called the “diathesis stress model,” this theory states that some people have a genetic predisposition for certain mental illnesses, and with enough environmental stress, these conditions will develop. Therefore, in turn, we can say that some horses are predisposed to develop ulcers, but require the right situational conditions to do so.