From the egg, baby crocodiles call to each other and to mom

For the first time, researchers have shown that the pre-hatching calls of baby Nile crocodiles actually mean something to their siblings and to their mothers. The calls—which are perfectly audible to humans and sound like "umph! umph! umph!"—tell the others in the nest that it's time to hatch, according to the report in the June 23rd issue of Current Biology, a Cell Press publication. Those cries also tell the mother croc to start digging up the nest.