The work proposes to continue research on the rhythms and cycles of small mammals in arid habitats, and similar research in a laboratory setting. In the field, the method will be to take infra-red photographs of animals visiting automatic bait-stations. From these photographs, the species can be determined as well as the time. Laboratory procedures are more complex but result in functions relating amount of activity to time of day, and these data can be repeated for different exerimental conditions such as foraging effort required.