For some time, scientists have known, that birds, as well as other oviparous (egg-borne) animals, are able to perceive information from the outside world, in order to prepare themselves for when they hatch. This ability is crucial for many of them, as unlike mammals, they are all alone inside their egg and cannot count on their mother to help them in adapting to their environment. In the last couple of years new research suggests that these animals may not be as solitary as previously thought.
Instead of simply reacting to changes in their surrounding or the calls of their parents they may be actually communicating and exchanging information with their siblings. Based on the findings of one team in 2014 we know that baby turtles use vibrations and sounds to signal to others that they are about to hatch. This way they can all come out of their shells at the same time, which gives them a certain advantage. There is safety in numbers, and this increases the chances that at least some of them will make it safely to the sea. This survival mechanism has also been observed in other animals, like birds and crocodiles.
Another more recent experiment was developed to shed some light on the exact manner of this shell-to-shell communication. A research team in Spain gathered a sample of wild seagull eggs and divided them into groups of three, which were then placed into incubators. From each group two of the three eggs were taken out every day and placed into a soundproof box. For half of them – the control – they just remained there for a while and then were returned to the incubator. The other half was played the sound of an adult’s alarm call.
As expected, the chick in the experimental half took longer to hatch and when they emerged, they crouched lower to the ground and made less noise – a defensive behavior adapted to living in a dangerous environment. What is surprising is that this development was present in all three chicks within the group and not only to the two, subjected to the noise. This clearly shows that the bird embryos exchanged valuable information.