Microhabitat Preferences of Bullfrog Tadpoles (Rana catesbeiana) of Different Ages

I experimentally investigated the habitat use preferences of bullfrog (Rana catesbeiana) tadpoles of different ages (early, first-year vs. late, second-year, premetamorphic) in the laboratory. Early tadpoles showed a preference for non-vegetated areas, whereas late tadpoles showed no preference. Early tadpoles were seen more often over small, gravel substrate as opposed to large rocks, whereas late tadpoles showed no preference. Early tadpoles preferred medium depths, whereas later tadpoles preferred deeper water. Thus, it appears there may be habitat preferences in bullfrog tadpoles, and that these preferences may change over time.