As of yet, the systematics of the Asiatic wild ass remain unclear. Some scientists assume that all of the eight different wild ass populations scattered across Asia are all subspecies of one single species, i.e. the Equus hemionus; other scientists, however, categorise the Asiatic wild ass into two to three different groups, the Equus hemionus, the Equus khur and the Equus kiang. The IUCN Red List (International Union for the Conservation of Nature) classifies both the Persian onager (E. h. onager) and the Turkmenian kulan (E. h. kulan) as "critically endangered"; the Indian khur (E. h. khur) is considered "endangered", whereas the remaining subspecies, i.e. the Mongolian dziggetai (E. h. hemionus), the Eastern kiang (E. h. holdereri), the Southern kiang (E. h. polyodon) and the Western kiang (E. h. kiang) are all defined as "vulnerable". The Syrian wild ass (E. h. hemippus) has already become extinct.
Status in the Wild
Today, the wild population of the onager is restricted to two geographically separated regions in Iran: one population can be found in the Bahram-e-Goor reserve in the province of Fars, southeast of Shiraz; the other is located in the Touran reserve in the northeast of the province of Semnan. In 2002 it was estimated that the reserves contained 91 and 471 animals, respectively. There are several factors that threaten the onager's survival: from poaching and the destruction of habitat to competition for food with domesticated livestock and disruption during the period of reproduction. The smaller a population is, the graver the loss from sickness or drought; additionally, the populations are severely threatened by genetic depletion.
Between 1954 and 1973, 55 onagers were captured in Iran and then placed in various zoos. On January 1st 2010, 103 onagers (41.62) were registered in the International Studbook (initiated in 1954). The Canyon Colorado Equid Sanctuary, owner of forty-seven onagers (the largest population so far), is placing its animals in other institutions and officially withdrew from the shared conservation breeding programme in 2007. Worlwide there are 21 institutions left breeding this threatened species. In Europe, too, some owners have withdrawn from breeding onagers, a fact which exacerbates the problems of placing surplus animals and the establishment of bachelor groups. Eventually, the zoo population will suffer from advanced age and a decline in fertility. Within the European Endangered Species Programme there are 16 Institutions breeding onagers. These days 79 animals, 30 males and 49 females, are living in these European zoos. In 2004, a species committee was initiated under the guidance of Tierpark Hagenbeck in Hamburg, Germany, to coordinate the efforts towards breeding the onager. The Werner Stamm Foundation is participating in this committee since January 2010.
All subspecies of the Asiatic wild ass - especially the most highly endangered onager - are of high cultural and biological value. Their historical areas of distribution overlap with the range of wild horses; however, the Asiatic wild asses also populate the most barren desert environments, which have never been ventured into by wild horses. In order for such a large herbivore to be able to survive in such barren vegetation, tremendous physical adaptations are necessary; however, these adaptations, as well as the Asiatic wild ass' incredible endurance, remain an unexplained phenomenon.
EAZA Equid TAG (Taxon Advisory Group) Recommendations
The EEP, the European Endangered Species Programme, must be intensified at all costs. The zoo population must be expanded swiftly in order to ensure the animals' genetic viability and health. There is an urgent call for new owners to initiate further breeding or bachelor groups. The genetic basis of the European onager population has been established; now these findings must be implemented forcefully and quickly!
The Onager and the Werner Stamm Foundation
The Werner Stamm Foundation has been breeding onagers for more than 30 years now: the first of 54 foals was born in 1976. However, the population is stagnating. Unfortunately, the difficult situation the worldwide zoo population finds itself in is also mirrored in our own enclosures: almost one third of the newborns have died shortly before or after birth. The sex ratio has also been unfavourable: 37 stallions and only 17 mares have been born, making it difficult to place the surplus stallions in other institutions. Other zoos are facing similar difficulties, which all have a negative effect on breeding. Thanks to the support of the species committee we were glad to welcome two young females from Augsburg resp. Montpellier in 2010, and we hope, these two beautiful animals will help us to improve our breeding success in the group of now one stallion and four mares. The Werner Stamm Foundation is pinning its hopes on the species committee's coordination efforts; pursuing the aims of the EEP, the foundation will continue to dedicate its resources and experience to a better understanding of this species.