Can desert rodents better utilize low quality roughage than their non-desert kindred?

The ability of a desert rodent to exploit, dry, low quality plant material and cope with shortage of adequate food, was studied in fat jird Meriones crassus a Saharo-Arabian gerbil, and compared to that in Levant vole Microtus guenteri. A high retention time of food in the gastrointestinal tract, mainly in the caecum, of fat jird, as well as a high rate of volatile fatty acid absorption from its in situ perfused colon, are probably the major factors in lending the jird its efficient digestive capacities. Both these characteristics are less pronounced in Levant vole. A low rate of energy metabolism as well as a higher capacity to digest dry plant materials help fat jird cope with shortage of food. -from Authors