Desert NWR is home to many species of wildlife that are supported by a wide variety of vegetation communities over a large elevation range. Approximately 320 bird species, 53 mammal species, 35 reptile species, and four amphibian species have been identified in the different communities on the refuge, as well as over 500 plant species.
Most mammals and reptiles cannot withstand the high desert temperatures for long periods of time. To adapt to the harsh daytime temperatures, many mammals and reptiles on the refuge are active at night, or nocturnal. This makes it difficult to observe much of our wildlife on the refuge.
An exception to this is the animal the refuge was established for, the desert bighorn sheep. Bighorn are active during the day, or diurnal, and can be seen in the hottest part of the summer around waterholes.