The Dallas Zoo says a female lion died Sunday after it was attacked by another lion.
The attack was witnessed by guests at the zoo.
In a tweet, the zoo said workers were "heartbroken" over the attack, and urged others to send good wishes to the staff.
The lions are part of the zoo's Giants of the Savanna exhibit in a section called Predator Rock, featuring five lions and two cheetahs, according to an undated news release from the zoo.
WFAA's Marie Saavedra will have a live update on News 8 at 5:30