When they hear the warning cries of adult gulls:
Yellow-legged gull embryos exposed to the warnings of adults and neighboring embryos that had not been exposed to the sounds both displayed a series of behavioral and physiological changes when newly hatched, according to a study published Monday in Nature Ecology & Evolution. By vibrating, the embryos exposed to the call appeared to transfer knowledge of the threat to the others in their nest—the first time such a behavior has resulted in observed changes to clutchmates.
Just as human babies register sounds they hear from the womb, embryos within bird, reptile, amphibian and insect eggs use sensory clues to glean information about their environment. …
“Sounds can give a lot of information to embryos, and they seem to be using it to shape their development to their particular conditions,” says behavioral ecologist Mylene Mariette of Deakin University in Australia, who was not involved in the study.
Jennifer Leman, “Bird embryos vibrate to warn one another of danger before they hatch” at Scientific American
Well, if the embryos are shaping their development in response to warning cries, that puts a whole new spin on “evolution.”
This was the first time we had heard the expression “embryo-to-embryo communication”:
“These results suggest a degree of developmental plasticity based on prenatal social cues, which had hitherto been thought impossible,” Mariette and Buchanan report.
Although chicks tuned in to siblings’ vibrations found themselves better-equipped to respond to danger, Science Alert’s Michelle Starr notes that this advantage came at the cost of reduced energy production and growth. Still, Sheikh writes for the New York Times, the informational advantage represented by nestmates’ warnings “could mean the difference between being eaten or not.”
Meilan Solly, “Unhatched Bird Embryos Communicate With Siblings by Vibrating Their Shells” at Smithsonian Magazine
It would be hard to quantify the advantages of being eaten.
No wonder there are so many gulls in the world.
See also: Does intelligence depend on a specific type of brain?
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