Samantha Monier, undergraduate thesis, Bard College, spring of 2012
Abstract:
If an animal invests too much time searching for and handling food items the animal may exert more energy foraging than it gains. The more experience an animal has with a given food item, however, the quicker it should be able to find and consume its prey. In this experiment, I created a situation where animals must decide between a high-quality food with an extended handling time and a lower-quality food with a lesser handling time.
I presented captive lemurs, Lemur catta and Varecia variegata, with puzzles to solve for a high-quality reward. This is a risk sensitive task--if the lemurs attempt the puzzle, they may be rewarded with a high-quality food or they may be unable to solve the puzzle and exert energy for no reward. In this experiment, however, lemurs could choose to forgo the puzzle and consume a low-quality food that was available for immediate consumption. In some organisms, females may adopt more energy saving strategies than males owing to their greater reproductive investment. I found that as males became more proficient with a puzzle, and the time it look them to complete the puzzle decreased, the percentage of trials they chose the high-quality food increased. Females, on the other hand, consistently chose the low-quality (no risk) food regardless of their puzzle completion time.