The Hindu : Front Page : The call of the unhatched

Online edition of India's National Newspaper
Wednesday, Jun 25, 2008
ePaper | Mobile/PDA Version

Front Page

Front Page

The call of the unhatched

Ian Sample

Device thought to be critical to the survival of the animals

London: Baby crocodiles call from their eggs to tell others in the nest when it is time to hatch, scientists have discovered. The calls, described by one researcher as an “umph, umph” sound, are thought to be critical to their survival.

By hatching together, baby Nile crocodiles increase the chances that a parent will remain at the nest and be able to protect them from predators in their first hours of life, scientists believe.

Writing in Current Biology, Amelie Vergne and Nicolas Mathevon, at Jean Monnet University in Saint Etienne, France, describe how they divided crocodile eggs which were due to hatch within 10 days into three groups. One was played recordings of the pre-hatch calls made by baby crocodiles, a second was played random noises and a third left in silence.

The researchers found that eggs played the pre-hatching calls often answered back, with many of them wobbling a little. After 10 minutes, all of them had hatched.

Of the eggs in the other groups, only one egg that was played random noises hatched shortly afterwards, with the rest not emerging until at least five hours later.

“Most mortality occurs early in life and hatching vocalisations might well attract predators. Adult presence at the nest and its response to juvenile vocalisations may offer protection against potential predators,” Mr. Mathevon said. “It is important for all embryos in the nest to be ready for hatching at the same time so that they all receive adult protection.”

The scientists believe the calls may have evolved in a group of reptiles that preceded modern crocodiles and birds, which also produce pre-hatching calls. — © Guardian Newspapers Limited, 2008

Printer friendly page
Send this article to Friends by E-Mail

Front Page