Early hatching decreases jumping performance in a direct‐developing frog, Eleutherodactylus coqui

Summary1 Differences in timing of development can greatly affect morphology and locomotor performance, which are of crucial importance in juvenile organisms. Early hatching in amphibians can occur in response to egg threats, and early hatched individuals may suffer the costs of physical immaturity posthatching. 2 We measured maximum jumping performance for early hatched (EH) and normal hatched (NH) froglets of the direct‐developing frog Eleutherodactylus coqui on both a wet and a dry substrate. Snout–vent length, hindlimb length and mass were compared with jumping ability and behaviours on the wet substrate were scored. 3 EH froglets had lighter mass, shorter relative hindlimbs and performed more poorly on both substrates than NH individuals. Between groups, hindlimb length and snout–vent length scaled higher with mass than the expected geometric scale. EH froglets also engaged in more walking and swimming behaviour than did NH froglets on wet substrates. 4 We found that EH froglets have shorter relative hindlimbs and poorer jumping performance than NH froglets. EH froglets may compensate for their poor jumping ability by using other forms of locomotion. Limbs that are longer than theoretically predicted may help these terrestrial organisms escape forest‐floor predators.