The executive director of the American Association of Zoo Veterinarians said he's not surprised to hear about the death of a lion while fighting with another lion at the Cheyenne Mountain Zoo.
Dr. Rob Hilsenroth said predicting animal behavior and preventing fights among animals is impossible.
"Animal fights are common in the wild," he said. "They might be even less common in (captivity) because we make efforts to prevent them."
Jamila, a 6-year-old lioness born at the zoo, was killed Thursday by Abuto, a 2-year-old male lion, during a fight Thursday morning in the main lion exhibit. Abuto arrived in January to be gradually introduced to the existing pride of four females and breed with Jamila's two sisters.
"A guest informed the keepers that the lions were fighting," said zoo spokeswoman Erica Meyer. "They immediately responded and tried to intervene with spray from a fire extinguisher and noise distractions, as is the standard protocol."
Hilsenroth responded to comments from witnesses who said keepers were slow to respond to the fight.
"When animals like lions really go at it, there's not much humans can do," he said. "We have darts but it takes a while to get them ready and the fight's usually over by then."
Hilsenroth said fights and occasional deaths are part of the risk of raising captive animals to save wild species from becoming endangered or extinct.
"We're doing the best we can, but we don't have all the answers," he said. "It sounds like the zoo did everything it was supposed to."