Investigated activity and exploratory behavior in 57 male Mongolian gerbils and 57 male Sprague-Dawley albino rats on 2 consecutive days using a Greek cross maze with black, white, striped, and checkered arms. 3 measures were taken: compartment of 1st choice, frequency of entrance into each compartment, and behavioral time sampling of each S's location during each 180-sec trial. Results indicate that handling habituation increased activity for both species and that gerbils were more active and varied in exploratory behavior (preference). Individually housed rats showed less exploratory behavior and activity than did group-housed animals. It is suggested that reported learning differences between rats and gerbils may be attributed to species differences in exploratory tendencies. (PsycINFO Database Record (c) 2006 APA, all rights reserved)