Two endangered addax antelopes were born at the Brookfield Zoo in Illinois and two more calves are on their way in the coming weeks.
One calf was born June 7 and the second was born June 22 weighing in at 19 pounds.
Nearly 200 of the animals live in 19 accredited North American zoos.
The Brookfield Zoo had its first addax birth in 1941 and has since contributed 141 calves to the North American population of the animal.
The addax antelope is known for its adaptation to live in drier, desert climates. Its hooves are wide and large, allowing it to walk on top of loose sand. Its legs are shorter than most antelope to help steady it on shifting sands.
The animal can go nearly its entire life without drinking water, deriving moisture instead from sap of vegetation and dew.