Animals living in Arizona Animal rattlesnakes Number of species 11 r The Western Diamondback Rattlesnake is common in the Sonoran Desert region of Arizona. Note the two heat-sensing pits, located below each eye. These “pits” help the rattlesnake locate its prey. reptiles 94 (including the 11 rattlesnake species) amphibians 22 birds 432 mammals 137 freshwater fish 46 r The cactus wren is the largest wren in America. It is found throughout the desert areas of the southwestern United States and northern Mexico. Its football-shaped nest is built in the middle of a thorny cactus or bush. The Mountain Lion is also known as a Cougar, Panther, and Puma. It is found throughout North, Central, and South America. Chapter 2 • Arizona Faces and Features  23