While today’s domestic horses rely on humans for many of their survival needs, a recent study by researchers in Germany demonstrated that domestication has not removed all their "wild" abilities. The results of the study, led by Lea Brinkmann, MSc, and colleagues at the University of Göttingen in Germany, indicate horses can still slow their body processes to conserve energy when food is short and temperatures are cold, important survival characteristics for their wild ancestors.

Although research has revealed signs of hypometabolism, or slowing of body processes, in the Przewalski horse, the closest living wild relative of the domesticated horse, previous research suggested that today’s livestock had lost that ability because selection pressure was not needed to maintain it.

For the current year-long study, Brinkmann and her team evaluated 10 domestic Shetland ponies accustomed to outdoor housing. The ponies, aged 4 to 16 years, resided in semi-natural outdoor conditions: pasture in summer and paddocks with open stables in winter.

In summer the ponies had access to water and grass and were provided with hay, straw, and a mineral supplement. In winter the researchers split the ponies into one control group and one feed-restricted group to simulate natural seasonal food shortages; the feed-restricted group received first 80%, and then 70%, of recommended energy and protein requirements. Researchers recorded the ponies’ ambient temperature, subcutaneous temperature, locomotor activity, lying time, resting heart rate, body mass, and body condition score