Rock Squirrel
Spermophilus variegatus
This Rock Squirrel was observed along the Salt River at Phoenix, Arizona, USA. Oct. 2009.
These large ground squirrels are common in the Sonoran Desert on rocky slopes and sometimes along desert washes. They make a loud, high-pitched, barking if danger is nearby - often times the hiker will hear this and suspect that there is a predator nearby - such as a coyote or soaring hawk - unless of course the squirrel is instead alarmed by a noisy hiker.