National Zoo scimitar-horned oryx going into the wild

These four scimitar-horned oryx are among the nine that were returned in December 2007 to Tunisia, where they have been extinct since the late 1970s. A male oryx from the Smithsonian's National Zoo's Conservation and Research Center in Front Royal, Va., was included in the group. The animals will eventually be reintroduced into the wild. Credit: Tim Wacher