Data from: Stable isotopes reveal diet shift from pre-extinction to reintroduced Przewalski's horses

The Przewalski's horse (Equus ferus przewalskii), the only remaining wild horse within the equid family, is one of only a handful of species worldwide that went extinct in the wild, was saved by captive breeding, and has been successfully returned to the wild. However, concerns remain that after multiple generations in captivity the ecology of the Przewalski's horse and / or the ecological conditions in its former range have changed in a way compromising the species' long term survival. We analyzed stable isotope chronologies from tail hair of pre-extinction and reintroduced Przewalski's horses from the Dzungarian Gobi and detected a clear difference in the isotopic dietary composition. The direction of the dietary shift from being a mixed feeder in winter and a grazer in summer in the past, to a year-round grazer nowadays, is best explained by a release from human hunting pressure. A changed, positive societal attitude towards the species allows reintroduced Przewalski's horses to utilize the scarce, grass-dominated pastures of the Gobi alongside local people and their livestock whereas their historic conspecifics were forced into less productive habitats dominated by browse.普氏野马（Equus ferus przewalskii）是马科现存唯一的野生马类，也是全球为数不多的几种在野外灭绝后经圈养繁育成功挽救，并顺利重返野外的物种之一。然而目前仍存在顾虑：经过多代圈养后，普氏野马的生态学特征，或是其原分布区域的生态环境，已发生可能危及该物种长期生存的变化。本研究对准噶尔戈壁（Dzungarian Gobi）地区灭绝前及重新引入的普氏野马的尾毛开展稳定同位素年代学分析，检测发现二者的同位素饮食组成存在显著差异。其饮食结构已从历史上冬季为混合取食者、夏季为草食者，转变为如今全年均为草食者，这一转变的最合理解释是人类狩猎压力的解除。当前社会对该物种的态度已转为积极，使得重新引入的普氏野马能够与当地居民及其牲畜一同利用戈壁地区稀缺的草本主导型牧场；而历史上的该物种种群则被迫栖息于生产力更低、以木本植被为主的生境中。