Onager the Zygophyllaceae form an important component of the diet of the Mongolian wild ass. The onager is preyed upon by apex predators such as Persian leopard and striped hyenas. A few cases of onager deaths due to predation by leopards were recorded in Iran. Though leopards do not usually feed on equids as in Africa, this may be because Persian leopards are larger and strong enough to prey on Asiatic wild asses. In the Middle East and the Indian subcontinent, Asiatic lions and tigers were the biggest predators of onagers. They were also formerly preyed upon by Asiatic wild dog,
Onager (weapon) could be winched back again. The onagers of the Roman Empire were mainly used for besieging forts or settlements. They would often be armed with large stones that could be covered with a combustible substance and set alight. The onager was used from the 4th century AD until the 6th century AD. The late-fourth century author Ammianus Marcellinus describes 'onager' as a neologism for scorpions and relates various incidents in which the engines fire both rocks and arrow-shaped missiles. The late-fourth or early-fifth century military writer Vegetius stipulates that a legion ought to field ten onagers, one for each cohort.