Even though Tucson is in the Sonoran Desert, it has quite a few species of native and non-native amphibians, such as this pale Canyon Treefrog (Hyla arenicolor).
While Canyon Treefrogs are generally found in the canyons around Tucson, I have never seen one in a tree. These and other amphibians can be found here in riparian areas such as canyon streams or natural springs, as well as in artificially constructed water sources like lakes or ponds.
Unlike Canyon Treefrogs, our native toads are also very common in the desert, far from any permanent water source. Toads will hibernate under the ground for most of the year. They will emerge at night during the summer, monsoon rainy season to mate and gorge themselves on the abundance of insects. Heavy, monsoon rains cause usually dry desert washes to flow and large, muddy puddles are created where toads can breed. The eggs and tadpoles of desert toads develop rapidly, usually before the puddles dry out.