In many species, ranging from crocodiles and birds to humans, embryos
can perceive and even produce sounds before birth. Surprisingly
however, the implications of such embryonic capacities
for developmental programming had not been recognized until recently.I
revealed this novel function of prenatal communication by showing
that zebra finch parents adaptively alter their embryos’ development
at high ambient temperatures, by emitting a peculiar vocalisation
during late incubation. Both in the wild, and under controlled thermal
conditions in the lab, parental calling is specifically triggered by
high air temperatures, and interestingly, is predicted by individuals’
body mass. In a large playback experiment in incubators, I show that
exposure of embryos to this call alone adaptively alters subsequent
nestling growth in response to nest temperature, and influences
individuals´ thermal preferences and thermoregulation capacity as
adults. Together, the findings demonstrate that the effect of the
prenatal acoustic environment on development is considerably greater
than currently acknowledged, and shed light on a novel mechanism for
thermal adaptation in birds.