Horse Hair Reveals Hidden Clues of Behavior, Ecology

It might seem strange, but horse hair can actually reveal hidden clues of the animal's behavior and ecology, according to a new study.

A horse's lifestyle leaves chemical traces in their hair, which scientists can then analyze. This involves the analysis of isotopes, which are variants of a chemical element with different atomic weights. The ratio of different isotopes of hydrogen, oxygen, carbon and nitrogen in a sample can provide important insights on water intake, nutrition and habitat, for example.

In horses, the analysis of tail hair is especially effective, as the length of the hair can provide information over a long period of time. However, determining the exact period of time that corresponds to a segment of hair is not trivial because hair does not grow at the same rate in all horses.

To solve this dilemma, researchers at the University of Veterinary Medicine Vienna developed a method to correctly assign individual hair growth to seasons and thus to a specific time frame. They published their findings in the journal Rapid Communications in Mass Spectrometry.

During the study, the team investigated the ecology of free-ranging horses and wild asses in the Gobi desert of Mongolia. They focused on the extreme climatic conditions of the Mongolian Gobi, where temperatures vary greatly at different times of year, and thus so does the composition of the chemical elements in the hair.

By comparing the isotope data from hair with satellite information freely available from NASA's Earth Observing System Data and Information System (EOSDIS), the researchers assigned a summer-winter rhythm to each hair. This allowed them to calculate the exact time corresponding to one centimeter of hair.

With this unique approach, they found that, on average, the tail hair of Mongolian wild asses reaches one centimeter in 19 days. Przewalski's tail hair takes 17 days and the tail hair of domestic horses only 13 days to grow one centimeter.

"Our method makes it possible for the first time to establish exact time lines for an animal's ecology and behavior. Previous time lines were estimations and not entirely accurate. Now researchers have a relatively simple method with which to correctly interpret their data," first author Martina Burnik Šturm said in a statement.

Tail hair is assumed to provide researchers with information about the ecology and behavior of Przewalski's horses, wild asses and free-ranging domestic horses in the Mongolian Gobi.

All three species share the same habitat in a 9,000-square-meter strictly protected area of southwest Mongolia. Closely related species usually compete for food, and given that the grassland in this area is quite barren, researchers would expect that competition between these groups is fierce.

And yet, these species are all able to peacefully co-exist in such close proximity, and researchers hope that this study helps shed light on horse behavior and ecology.

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