Movie 3

Manual egg-jiggling stimulus. Individual Agalychnis callidryas eggs were jiggled with a blunt metal probe, alternating 15 s of stimulation and 15 s of rest for 5 min or until the egg hatched. The clip shows 5 s of stimulation, after which the embryo begins shaking motions – indicating the start of the hatching process – and the experimenter ceases stimulation. Then the embryo hatches.