It is hypothesized that male gray tree frogs who perform longer duration mating calls are more genetically fit. Female mating partners are also more likely to prefer a male that has the longer duration of mating call, compared to a frog that has a shorter duration mating call. This was identified by studying half-siblings which were mated with males with varying durations of mating call. It was found that males with longer mating calls had better outcomes and better chance of survival in the juvenile stage of life. There was an decrease in mortality in the larval stage, and the overall success was measured by frogs able to survive to adulthood. It is interesting to know that frog mating calls could have such a suggestion that they would produce more fit offspring than frogs that could not produce the same length mating call.