Most mammals and reptiles cannot withstand high temperatures for long periods of time. Many mammals and reptiles are nocturnal, coming out of burrows to feed only at night. The best times to observe mammals and reptiles are in the early morning and evening hours and in the spring or fall when temperatures are cooler. An exception is the adaptive desert bighorn sheep, which is most easily viewed during the hottest part of the summer when they are concentrated at or in the vicinity of waterholes. Since the precipitation is low, the few amphibians living on the Refuge are found only at the permanent springs around Corn Creek.
Fifty-two species of mammals and thirty-one species of reptiles and amphibians have been recorded on the Refuge. In addition, another eight reptile and amphibians are suspected to reside here, but have not been confirmed as being present.
One endangered species of fish, the Pahrump poolfish, previously resided in the permanent springs at Corn Creek. The small fish was extirpated (no longer found) on the refuge due to the introduction of non-native wildlife such as goldfish, turtles, and crayfish which eat the poolfish's eggs and compete for the same food. A refugium was constructed, and the Pahrump poolfish were reintroduced into this more secure setting.
Over 240 different species of birds have been recorded on the refuge. Corn Creek Field Station, the main entrance to the Refuge, has several spring-fed ponds and many types of vegetative cover. Consequently, this locality provides the best opportunity to bird watch. The best time to see the greatest variety of birds is during the fall and spring migrations, especially in the early morning or late evening. Calm, mild days are preferable to windy, cold days. A refuge bird list is available at the refuge and online.