Przewalski’s horses are naturally stressed during winter and spring, making them more likely to get sick if they face additional stress, such as from human disturbance or severe weather, during these times of the year. | Photo: iStock

Wild horses don’t hibernate. But their bodies do react to the “stress” of tough winter conditions. International researchers have learned that Przewalski’s horses enter an “allostatic state” in winter—meaning their cardiac and metabolic activity slow to deal with the stress. But by spring, they move into “allostatic load.” That means they need extra energy for seasonal routines and are more likely to develop signs of wear and tear.

By understanding these natural, seasonal stress patterns, scientists are better equipped to continue preserving this endangered species, said Friederike Pohlin, DVM, of the Department of Integrative Biology and Evolution in the University of Veterinary Medicine Vienna’s Research Institute of Wildlife Ecology, in Austria.

“As Przewalski’s horses are ‘naturally stressed’ during winter and spring, they are more likely to get sick and die if additional load is put on them, such as from human disturbance or severe weather, during these times of the year,” Pohlin said. “By knowing this, conservation managers can take respective measures—like not disturbing the horses, or taking the horses away from localized areas with severe weather—that ultimately reduce stress and improve equine welfare