Bighorn sheep have been roaming Nevada’s 314 mountain ranges for over 28,000 years. Moreover, bighorn sheep were the most numerous ungulates in Nevada prior to European settlement. It is estimated that over 30,000 wild bighorn sheep ranged throughout Nevada in 1860. By 1960, however, the number of bighorn sheep in Nevada plummeted to an estimated 3,000. Bighorn sheep were extirpated throughout much of their historic Nevada range. What happened? The decline in the number of bighorn sheep in Nevada was due to several factors including: 1) excessive unregulated hunting (which differs significantly from regulated hunting), 2) competition with domestic livestock, 3) diseases from domestic livestock (especially domestic sheep and goats), 4) loss of watering areas, and, 5) loss of habitat due to human causes. After the dramatic decline of wild bighorns, Nevada Department of Wildlife and hunting organizations worked together to find ways to restore bighorn sheep. This lesson plan explore their opportunities, challenges and success. If you're a teacher wishing to access answer keys, please contact firstname.lastname@example.org with your school email address to receive the passwords.