The turtle moms that ‘talk’ to their eggs before they hatch
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Turtles aren’t known for their parental instincts, but the arrau is an exception. The discovery is spurring a race to save the chatty species.
Researchers for decades thought of aquatic turtles as hard of hearing and mostly mute. One popular 1950s textbook claimed turtles “make no appreciable use of sound in their daily routine.” In the world’s rumbling rivers and cacophonous oceans, the lumbering reptiles appeared to tread along without much to say.
But recent recordings of these turtles’ first “words” — before they even hatch — challenge notions not just of the turtles’ capacity to communicate, but also of their instinct to care for young. Now the discovery has spurred an urgent count of this talkative turtle’s numbers, and may shape protections for shelled creatures in the Amazon and beyond.
For other kinds of turtles, the mothering usually ends at the beach. Many turtle hatchlings are left by their parents to fend for themselves.
But that’s not the case with the arrau. After nesting, females often hover by the shore for up to two months waiting for their eggs to hatch.
So Ferrara and her colleagues wondered: are mother turtle and child turtle communicating with one another? To test the idea, her team sent months taping the turtles — on land and underwater, in the wild and in a swimming pool.
The team recorded a wide repertoire of whisper-quiet calls from arrau of all ages.
Embryos appear to chirp together to coordinate hatching and digging up to the surface. With so many jaguars and other predators lurking, it is safer for baby turtles to move en masse toward the river.
The mothers, meanwhile, approach and respond to the calls of their young. Once the hatchlings reach the water, the baby turtles migrate down the river with the adult females, Ferrara’s radio-tracking research shows.
When her team published an early study on turtle vocalizations a decade ago, Ferrara said, academic journals resisted putting the phrase “parental care” in the title of a study about turtles.
“At that time it was very hard to publish,” she said. “It was something really new.”
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