Crocodiles can natter before they’re even born, according to a brilliant new study.

Writing in Current Biology researchers show that baby crocs use calls from inside their eggs to synchronise their hatching. Mother crocs also listen in for the calls, and swiftly dig up buried eggs when they hear them, according to Amélie Vergne and Nicolas Mathevon of Université Jean Monnet in France.

“We can well suppose that hatching synchrony can be of vital importance for crocodiles,” says Mathevon (press release). “Indeed, most mortality occurs early in life and hatching vocalizations might well attract predators. Therefore, adult presence at the nest and its response to juvenile vocalizations may offer protection against potential predators.”

The methodology of this research is simply awesome.

First up the researchers looked at six different clutches of croc eggs. Some they played recorded pre-hatch crocodile calls to. Some they played random noise sequences. Some they played no noise to.

They found those eggs played pre-hatch noises emitted their own noises and started to hatch. Mother crocs also respond to the noise, they found when they removed eggs from nests and replaced them with speakers. Playing pre-hatch noises triggered most mothers to dig in the sand for their eggs to help their young to the surface.

Infuriatingly neither the paper nor the press release comments on how the researchers avoided being eaten by angry crocs during the work, at the La Ferme aux Crocodiles in Pierrelatte, France.

Watch a movie of the crocodiles here.

News coverage

Baby crocodiles talk to each other in their eggs – Daily Telegraph

Baby crocs start chatting even before they hatch – Reuters

Calls From Crocodile Eggs Serve as Alerts – NY Times