CREDITS: RICHARDJAMES1990/FLICKR, REPTILES PLUS/FLICKR, PFAUCHER/iNATURALIST, PAUL TAVARES/iNATURALIST, MOTH-_-MAN/iNATURALIST, OLIE TURNER III/iNATURALIST, ARIEL CABRERA FOIX/iNATURALIST Many reptiles — from turtles to lizards to crocodilians — turn out to communicate vocally, scientists are learning. Scientists are investigating what the various sounds mean — and discovering that the creatures may be more like birds and mammals than once thought Along the sandy banks of north India’s Chambal River, crocodile-like gharials glide silently through the water — but if a gharial spots a stranger, the quiet may be punctuated by a series of explosive pops. That popping sound — like a champagne cork being released from a bottle — has only recently come to scientists’ attention.
It’s unique to male gharials and results when one of the large reptiles fills its nasal cavity with water and then exhales rapidly: The water shoots through a bulbous outgrowth at the tip of the creature’s long snout. The sounds, which are often produced in sequence, appear to broadcast the male’s identity — each gharial’s “pop pattern” is unique. The gharials aren’t the only reptiles making surprising noises.
While mammals and birds are better known for their vocal communication skills, reptiles aren’t just quietly slinking about in the wild — they create their own soundscapes with chirps, squeaks, bellows and roars. Gharials are large crocodile-like creatures with long slender snouts; the males produce loud, underwater pops in a variety of social contexts. The gharial shown in this video was recorded in India’s National Chambal Sanctuary, home to most of the remaining individuals of this critically endangered species.
As researchers discover more of these sounds, they are also beginning to determine the importance of such vocal chatter to the animals’ social lives, from mating to parent-offspring interactions. Reptiles have largely been thought of as secretive creatures and “underappreciated for a long time with regard to social behavior,” says conservation biologist Sean Doody of the University of South Florida. Now that scientists are taking note of these varied vocalizations, says Brumm, the idea is to “to better understand what they’re saying.” When it comes to talkative reptiles, crocodiles are among the most well-studied.
Scientists have long known that, like their bird cousins, baby crocodilians produce sounds while they are still in the egg. These noises appear to synchronize hatching among siblings and to call their mom for help extracting themselves from their eggshells and leaving the nest. But over the past decade or so, it’s become clear that many turtles, too, make various clicks and chirps from within the egg.
Life in the soil was thought to be silent. To better understand turtle noises, evolutionary biologist Gabriel Jorgewich-Cohen, now at the National Institute of Amazonian Research, and colleagues looked at species with chatty turtle babies, such as South American river turtle, as well as more taciturn species, such as the western swamp turtle. The researchers found that while South American river turtles — with clutches of more than 100 eggs — have noisy turtle youngsters that synchronize their nest exit, hatchlings of species that lay fewer than 10 eggs are less likely to vocalize and to leave the nest together.
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