Our team has trained the onagers to voluntarily urinate on cue, allowing us to easily collect a sample for our endocrine lab to analyze. For doing the behavior asked of them, our onagers receive positive reinforcement in the form of a favorite food: apple biscuits. This training was a non-invasive and stress-free way for us to collect Sayeh’s hormones for analysis.
Once we determined Sayeh was in estrus, we put her and the filly’s father—a 14-year-old stallion named Mandrake—together for breeding. This training also enabled us to confirm Sayeh’s pregnancy and keep track of its progress. Typically, gestation lasts 365 to 368 days. Our newest filly is one of 48 Persian onagers born at SCBI since the breeding program began in 1975.
Fun Facts About Persian Onagers
- Onagers, in general, have very strong personalities. They are quite smart and irascible, so they often let keepers know what they are thinking in no uncertain terms! But, that also makes working with them and earning their trust a very rewarding part of our job.
- One of their most amazing adaptations is their ability to withstand extreme temperatures. Persian onagers are native to the semi-desert region of Iran, where it can get up to 120 degrees Fahrenheit during the day. In this environment, leaves and grasses provide the onagers with most of the water they need to survive, which distinguishes them from other equine species. Whereas a Przewalski’s horse may drink up to 12 gallons of water a day, a Persian onagers may drink only 1.5 gallons.
- One way to differentiate Asiatic wild asses from most domestic horses is by their “dun stripe”—a dark brown stripe that runs down their spine, from mane to tail. Persian onagers, Przewalski’s horses and domestic donkeys all have this trait.
This story appears in the September 2021 issue of National Zoo News. Want adorable animals in your inbox? Sign up for Zoo Emails!