EFFECT OF WATER ON RETENTION TIME AND FOOD-CONSUMPTION IN DEER MICE

Experiments were conducted to assess the effect of water on food consu mption and retention time in deer mice (Peromyscus maniculatus). We te sted whether increased intake of water, preformed in food or free drin king water, affects mean retention time and consumption of food. Mean retention times for diets of sunflower seeds (Helianthus annuus), comm ercial rat chow, and insect-seed mixtures were estimated by using 2-mm red thread markers. For all diets, mean retention time and food intak e were negatively and positively correlated, respectively, with water intake. Mean retention times decreased more rapidly with increased wat er content for sunflower seeds than for rat chow, suggesting that food type also may be important. Granivorous rodents may consume wet food items during periods of low water availability to increase energy inta ke rather than to satisfy water requirements.