State wildlife officials say a 10th 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 reported Monday that the ewe's corpse was found Friday and the cause of death is being investigated.
Game and Fish officials said most of the previous nine bighorn deaths were caused by mountain lions, including a pregnant adult ewe found Jan. 31 in an area of steep slopes and cliffs.
They sid an adult ram found Nov. 27 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.