- Burrows of Meriones crassus were studied in two habitats in the central Negev Desert. Burrows in the loess habitat were more complex than in the sand habitat. To measure the burrow microclimate, artificial burrows were constructed in natural habitats and equipped with temperature and relative humidity data loggers. Daily fluctuations of temperature and relative humidity in burrows were much lower than those of ambient air. Average burrow temperatures were higher than air temperatures. The difference between average daily ambient and burrow temperatures was higher in the sand habitat than in the loess habitat. Average relative humidity in burrows was lower than relative humidity of ambient air throughout the year in the sand habitat and in summer and autumn in the loess habitat. In winter and spring, relative humidity of burrow air was significantly higher than that of ambient air. The presence of nest material in the burrow chamber increased relative humidity. Laboratory experiments demonstrated that the presence of an animal in the burrow chamber increased soil water content at the chamber's floor and this effect persisted for at least two months after removal of animals.