ABILITY OF DIPODOMYS-MERRIAMI AND CHAETODIPUS-INTERMEDIUS TO LOCATE RESOURCE DISTRIBUTIONS

The ability of Merriam's kangaroo rat (Dipodomys merriami) and the rock pocket mouse (Chaetodipus intermedius) to locate sandboxes with food was studied in a series of three experiments using large laboratory arenas (6.9 by 3.7 m). In the first experiment, D. merriami learned the location of sandboxes after 3 nights with the same food distribution; after 4 nights, C. intermedius still had not located these sandboxes. When the foraging area was enlarged (6.9 by 11.1 m), D. merriami again located the food patch by the third trial. The performances of C. intermedius improved, but did not match the accuracy of D. merriami. The final experiment determined whether kangaroo rats detected food patches by smell. Sandboxes were never located efficiently when odor was the only cue available to kangaroo rats. These results indicate that D. merriami was more capable of locating food patches than C. intemedius and that this ability was a function of learning rather than olfactory cues.