Last November, Arizona wildlife officials started to re-introduce bighorn sheep to the Santa Catalina mountains north of Tucson. Thirty-one of the iconic animals were trucked in from a wilderness area, fitted with tracking devices and offloaded into the mountains.

But after that, another iconic creature, the native mountain lion, stalked and killed two of the bighorns. Then those mountain lions were shot and killed by Arizona Fish and Game.

From Tucson, Fronteras correspondent Michel Marizco reports on the costs and benefits of human attempts to balance out nature.