During the day, the soil temperatures in the desert can rise to 60° C (140° F) with low precipitation (30 cm/yr) resulting in low humidity (Campbell 1993).

 

Although the kangaroo rat lives in such an extreme environment, due to its nocturnal lifestyle and its burrow environment they are able to keep a positive water balance. Their nocturnal lifestyle allows them to avoid the hot day temperatures of the desert. They need not exposed to temperatures above their thermal neutral zone, therefore they do not need to expend excess energy or water to cool themselves. And most species rarely are exposed to temperatures above 35°C (95°F) (Carpenter 1966).

The burrows of kangaroo rats are normally located under a bush, such as the creosote bush (Larrea tridentata) with D. merriami.The burrows descend at least 25 centimeters which is the depth at which the daily temperature fluctuations first disappear and burrow temperatures rarely exceed 35°C. Not only do the shade of the bushes aid in buffering the hot daily temperatures, but the depth of the burrow minimizes energy and water expended to cool the animal (Carpenter 1966).

The burrows also have another added benefit in that they are humid environments. Because the burrows are cooler than the ambient temperature, the same amount of moisture in the air causes the cooler burrow to have a higher humidity than above ground. The higher the humidity, the less water needed before the air is saturated. A mammal such as the kangaroo rat has a water content of 66%. If an animal has a water content higher than the relative humidity, then they will lose water to their environment  (Schmidt-Nielsen 1997).

The average relative humidity of the nesting burrows is 42% (10 mg H₂O/L at 25°C), but the humidity can be as high as 91% depending on the species and the environment it lives in. D. merriami can retain a positive water balance above 10% relative humidity (2.2 mg H₂O/L at 25°C). Living in a humid environment allows kanagaroo rats to minimize their evaporative water losses (Schmidt-Nielsen & Schmidt-Nielsen, 1950; Schmidt-Nielsen & Schmidt-Nielsen 1951; Schelza & Knoll 1982).