The Smithsonian's National Zoo is mourning the loss of its elderly white-cheeked gibbon, a female named Mae, who died April 8. She was 43 years old and lived well past the median life expectancy of zoo gibbons, which is about 28 years old. Mae arrived at the National Zoo in 1976 from the Los Angeles Zoo. Because she was wild-born, her genes were very valuable to the gibbon population in human care. She contributed 10 offspring to her species' survival—seven males and three females. White-cheeked gibbons are considered endangered by the International Union for Conservation of Nature's Red List of threatened species. Visitors can see two white-cheeked gibbons and two siamangs on exhibit at Gibbon Ridge.

Photo Credit: Mehgan Murphy, Smithsonian's National Zoo

To download this photo in high-res, visit the Zoo's Flickr Page.