The tale of the horse’s tail – stable isotope analysis of tail hair to address ecological differences in three sympatric equid species

Photo of a Przewalsky´s horse biting the tail of another 1
Where does the stable isotope signature come from? (Graphic: M. Burnik-Sturm)
Graphic "Where does the stable isotope signature come from?" 2
Tail of a wild ass
Photo of tail of a wild ass 3
Mongolian domestic horses
Photo of Mongolian domestic horses 4
Mongolian riding horse´s tail
Photo of Mongolian riding horse´s tail 5
Fighting wild asses
Photo of fighting wild asses 6
Przewalski´s mare with foal
Photo of Przewalski´s mare with foal 7
Wild ass mare with foal
Photo of wild ass mare with foal 8
Przewalski´s horse in the Gobi desert
Photo of Przewalski´s horse in the Gobi desert 9

All equid species are similar in size and body shape and seem to occupy very similar ecological niches. Overlap zones among species are small and little work has been done to understand resource use and physical adaptations that explains species distribution. In the Dzungarian Gobi of Mongolia three equid species, the Asiatic wild ass (Equus hemionus), the re-introduced Przewalski’s horse (Equus ferus przewalskii) and the domestic horse (Equus caballus) share the same habitat and thus provide a unique opportunity for comparative ecological studies. However, continuous observations of free-ranging equid species in the harsh environment and over the large expanse of their ranges are impossible to conduct, whereas physiological measurements either require highly invasive techniques and/or the confinement to a captive or semi-captive environment.

Stable isotope analysis has become a powerful tool to study feeding ecology, water use or movement pattern in contemporary, historic and ancient species. Certain hair and teeth grow continuously and when sampled longitudinally can provide temporally explicit information on dietary regime and movement pattern. Wild equids were once abundant over a wide geographic range which made them ideal species for paleodietary and parleoclimatic reconstructions using isotope analysis. Results have been widely calibrated using isotopic signature variations from modern counterparts. As a consequence, there is an advanced understanding of the assimilation of dietary isotope composition, particularly carbon, into the horse tissue. In the proposed 3-year study we want to use isotope analysis of sequentially sampled tail hair from the three sympatric equid species as an indirect measure for seasonal feeding ecology, water use, movement pattern and metabolism.

The Przewalski’s horse is rather special as it became extinct in the wild, but has been re-introduced back into its original habitat. Prior to extinction in the wild almost no ecological information had been collected and many aspects of their original ecology are unknown (e.g. migratory behaviour). Comparing samples of historic autochthonous Przewalski’s horses with those of present day re-introduced Przewalski’s horses as well as sympatric Asiatic wild asses and domestic horses can be expected to help re-construct some of the original ecology profile of the Przewalski’s horse.


Duration  01 April 2012-30 September 2016

Science grant

FWF logo 10

FWF Project 24231 11


Research partner

IZW logo 12

PD Dr. Christian Voigt, Leibniz Institute for Zoo and Wildlife Research



Additional information


Scientific project contact

Dr.rer.silv. Petra Kaczensky, Research Institute of Wildlife Ecology, Vetmeduni Vienna

T. +43 (1) 25077-7181

Email Petra Kaczensky

Dr. Martina Burnik Sturm, Research Institute of Wildlife Ecology, Vetmeduni Vienna

T. +43 (1) 25077-7151

Email Martina Burnik-Sturm


General contact


Savoyenstraße 1
A-1160 Wien

T +43 1 25077-7900
F +43 1 25077-7941

Email FIWI