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The rupicolous noki or dassie-rat (Petromus typicus) is endemic to the south-west arid biogeographical region of Africa. Nokis are diurnal and, compared to nocturnal small mammals, are relatively easy to observe, yet few field studies have been completed. Using radio-tracking and direct observation, a population of nokis in Namibia was intermittently studied over 3 years to document their basic natural history. Temperature loggers and temperature-sensitive radio tags were used to determine that nokis do not have a labile body temperature and do not go into daily torpor. They spend nights deep in rock crevices, but seemingly do not build or use nests. During the cool winter months they bask in the sun at sunrise, and during the heat of the day they shelter in cool rock crevices. During the warm part of the year they bask less frequently. Because nokis have a low relative metabolic rate and a diet of seasonally poor-quality forage, their frequent use of solar basking and passive heat gain and loss from the massive rocks in their habitat is probably related to conservation of energy.