ATLANTA -- An adult female giraffe has died suddenly at Atlanta's zoo.
Zoo Atlanta says 7-year-old Mona died Wednesday and the cause of her death is unclear.
The giraffes weren't on exhibit Wednesday because of wet conditions in their yard following heavy rains the day before. Mona was in an outdoor corral behind the scenes when she collapsed.
Zoo deputy director Dwight Lawson called Mona's death a tragic loss, especially since she had shown no signs of illness or distress before collapsing.
Veterinary teams are trying to determine what led to her death. A necropsy has been scheduled for Thursday.
Mona and her half-sister came to Zoo Atlanta from Disney's Animal Kingdom in October 2007. Mona was the mother of Lily, who was born in July 2011.