Brief periods of prenatal auditory stimulation accelerate the hatching of Japanese quail Free

Many species of precocial ground‐nesting birds brood egg clutches whose eggs hatch within a short time of one another. This synchronization of hatching is mediated by acoustic communication between the individual members within a clutch [M. A. Vince, Anim. Behav. 14, 389–394 (1966)]. Audible clicks, which are correlated with the embryo's respiratory cycle, provide the basis for the inter‐egg communication. Experiments utilizing synthetic clicks (i.e., very brief, broad‐band burst of noise) have shown that the response of embryos to acoustic stimulation is dependent on their gestational age, the duration of the stimulating period, and the click repetition rate. A single very brief (2‐h) exposure to auditory stimulation at any point during the final three days of incubation accelerates the hatching of Japanese quail (Coturnix coturnix japonica). The three‐day sensitive period includes both prenatal and perinatal stages of incubation. The accelerated embryos do not differ from normal hatchlings in any of the behavioral or physiological measures examined to date. These results provide the first unequivocal evidence that such short‐term sensory stimulation can affect the rate of development of a vertebrate embryo. [Supported by NIH NS02675 and NS09244.]