According to the internet, the name of this little guy is quite a bit bigger than the animal himself... Ammospermophilus leucurus. We've developed a love / hate relationship with them. They're very animated and fun to watch, but they eat up all our cactus (including those heavily covered with spines!). Last weekend, we were surprised to see one run up on our patio and effectively flatten out like a pancake! They look like plump little things, but they can flatten themselves out so they are incredibly thin... very interesting!