Baby seabirds that have not yet hatched communicate with their siblings (兄弟姐妹) in neighboring eggs by vibrating (震动) their shells (蛋壳), scientists have discovered.
A study of yellow-legged gulls revealed one of the known examples of embryo-to-embryo communication. When exposed to the alarm calls of an adult bird responding to a dangerous predator, developing chicks apparently were able to convey the presence of danger to their nest mates by vibrating inside their eggs.
The team collected 9 yellow-legged gull eggs from Sálvora Island and sorted them into nests of three. When the eggs were six days off hatching, two of the three eggs in each nest were temporarily removed from the nest and exposed to either a recording of a predator alarm call or white noise each day until the chicks hatched. The noise was delivered four times a day at random for three minutes at a time. The third egg from each group remained in the nest.
It was found that the embryos in the shells responded to the external alarm calls by vibrating and sounding less, and that this message appeared to be passed on to the third nestmate. It was seen to copy the vibrations. It experienced genetic changes and had an increase in the production of stress hormones (荷尔蒙) as well.
“This kind of communication—embryo to embryo—can generate developmental changes that can have potential benefits to the birds after hatching,” said Noguera, the lead author of the study.
A rise in stress hormones makes birds more aware of their surroundings after hatching. When hatched chicks were exposed to alarm sounds, it was found that those who had listened to the noises previously in the eggs were quicker to run away and hide.
Noguera said the phenomenon was likely to occur in other bird species. His team now plans to investigate whether the chicks are able to pick up other clues about their external environment before hatching, such as how many other eggs are in the nest.
【小题1】What do the unhatched birds mean to do by vibrating shells?| A．Fight with a predator. | B．Play with their nest mates. |
| C．Seek care from adult birds. | D．Warn others of danger. |
| A．The theoretical base of the experiment. | B．The subjects of the experiment. |
| C．The process of the experiment. | D．The findings of the experiment. |
| A．The presence of danger. | B．The external environment. |
| C．The third egg in the nest. | D．The embryo-to-embryo communication. |
| A．It makes them mature earlier. | B．It helps them adapt to life after hatching. |
| C．It allows them to develop physically. | D．It strengthens bonds with their siblings. |
