Article from The UK Telegraph
Baby crocodiles "talk" to their mothers and their unborn siblings even before they hatch, perhaps indicating that they are ready to leave the egg, according to new research.
French scientists Amelie Vergne and Nicolas Mathevon of Universite Jean Monnet in Saint-Etienne noticed that the young reptiles make a noise, described as sounding like "umph, umph", in the moments immediately before they hatch. The researchers tested ten batches of crocodile eggs, dividing them in to three groups. One was played actual recordings of the juveniles' pre-hatching calls, one was played random noises, and one was left in silence. Eggs played the real recordings all hatched within ten minutes, while the other two groups stayed in their shells for another five hours at least.
Similarly, the mothers responded to the real calls. Without their knowing, the scientists dug up the eggs and put them in an incubator, replacing them with speakers. Mothers played the real sounds attempted to dig up the eggs, while those who heard random sounds did not. Writing in the journal Current Biology, Mathevon said many baby reptiles are eaten right after birth, so it may be important for them all to hatch together and for the mother to be there when they do. "In this sense, it is important for all embryos in the nest to be ready for hatching at the same time so that they all receive adult care and protection," he said in a statement.