State wildlife officials say a tenth bighorn sheep has died in the Catalina Mountains north of Tucson where 31 bighorns were released late last year. The Arizona Game and Fish Department reports that the ewe's corpse was found Friday and the cause of death is being investigated. Game and Fish officials say most of the previous nine bighorn deaths were caused by mountain lions, including a pregnant adult ewe found January 31st in an area of steep slopes and cliffs. They say an adult ram found November 27th 2013 likely died from a condition that led to heart failure. The 31 bighorns captured in mountains near Yuma were released in the Catalinas last November in an effort to rebuild a herd that disappeared from the range in the 1990s.