When male Sierran tree frogs first arrive on the scene, for example, their croaks are distinctly slower and less frequent than later in the season when it’s warmer, Pekny and colleagues report in a recent study published in Frontiers in Ecology and the Environment. Based on data collected when Pekny was a graduate student at the University of California, Davis, the scientists argue that female frogs pick up on the change in the mating calls’ cadence, too—and use those cues to help them decide which waters are warm enough to lay eggs in.