Effects of food size on foraging time and behavior of captive ring-tailed lemurs （Lemur catta）

Abstract

It is a common practice in zoos to provide chopped diets to exhibit animals for the purpose of increasing time spent foraging and reducing aggression between group-housed animals, but the studies to measure effects of this practice is still limited. In this study, 10 ring-tailed lemurs in captivity at NIFREL were examined for 30 minutes to observe their behaviors when fed chopped food (1×1×1 cm) or stick-shaped food (1×1×6 cm). As results, ring-tailed lemurs picked up chopped food directly from the floor using their mouths, whereas they ate stick-shaped food by holding it with their forelimbs. In the 30-minute observation, no significant difference was observed between conditions in percentage of time spent for feeding/foraging. On the other hand, the percentage of time spent for allo-grooming significantly increased when stick-shaped food was given (P <0.05). Although similar time-course change of their behavior was seen despite of different shape of food, auto-grooming behavior was significantly more often observed between 11 to 20 minutes in the observation when stick-shaped food was presented than so was chopped food. These results show ring-tailed lemurs could change their behaviors when fed small-chopped food or large stick-shaped food, whereas no extension of time spent feeding/foraging was observed which highlights importance of assessing the effect of feeding animals with chopped food.