Andazi, a 6-year-old eastern black rhinoceros, will soon give birth to the first member of her species born in Zoo Atlanta's more than 124-year history.
The first-time mother has entered her birth window, which officially began on July 23, 2013, and continues into late November 2013.
Just what day the more than 2,400-pound female will deliver is anybody's guess, but she is most likely to give birth in August or September.
Rhino gestation averages 14 to 18 months, and calves, which weigh 55 to 90 pounds at birth, are born without horns.
In preparation for the birth, Andazi will be off exhibit until she delivers her calf. Her mate, 8-year-old male Utenzi, will not share space with his new son or daughter; black rhinos are solitary in the wild.
Eastern black rhinos are a critically endangered species with an urgent conservation message.
Hunted almost to extinction in the 1980s, their populations have experienced near-catastrophic decline in recent years, largely as a result of poaching for their horns and other body parts, which are believed by some cultures to have curative properties.
Conservation programs and stringent patrolling of rhino habitat have helped populations increase to about 4,800 in the wild, but the species remains critically endangered.