Tail hairs reveal dietary choices of three horse species in the Gobi Desert

Date: November 30, 2016

Source: Veterinärmedizinische Universität Wien

Przewalski's horse, a species of wild horse that has been successfully reintroduced to the Gobi Desert, shares its pasture grounds with wild asses and free-roaming domestic horses. A scarce supply of food could lead to food competition among the different species, especially if they make the same dietary choices. A team led by researchers from Vetmeduni Vienna therefore chemically analysed the tail hairs of the animals to determine the seasonal dietary habits of the three species. While the wild ass switches from being a grazer in the summer to also browse in the winter, the wild and domestic horses eat exclusively grass all year round. In the lean winter months, this leads to increased food competition between wild and domestic horses. This realisation could help improve wildlife management measures for the Przewalski's horse in the future. The study was published in the Journal of Applied Ecology.

Przewalski's horses went extinct in the wild in 1968. Successful breeding programmes at zoos around the world helped to reintroduce the animals in the Great Gobi B protected area in southwestern Mongolia since 1992. The wild horses share the extreme habitat of the Gobi Desert with two other equid species: the Asiatic wild ass, also called khulan, and the free-ranging domestic horses of local nomads. For the preservation of the wild Przewalski's horse, it is important to understand if and how the three related species compete for food in the protected area.

Competition between Przewalski's horses and domestic horses in the winter

Martina Burnik Šturm and Petra Kaczensky from the Research Institute of Wildlife Ecology at Vetmeduni Vienna, in cooperation with the Leibnitz Institute for Zoo and Wildlife Research in Berlin, used a special method based on the chemical analysis of tail hairs to investigate the dietary habits of the animals. The analysis allowed them to determine the composition of the diet of each of the three species, which led to the discovery of increased dietary competition in the winter months.

The chemical analysis of the tail hairs revealed that Przewalski's horses and domestic horses are year-round grazers. Khulan, on the other hand, switch from grazing in the summer to a high proportion of foliage in the winter. "When food becomes scarce in the long winter months, competition can be expected especially between the two species of horse," explains Martina Burnik Šturm.

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