'Talking' Turtles Stick Together

It turns out that turtles use sound to stick together and care for young, according to the Wildlife Conservation Society (WCS) and other organizations.

While known for their longevity and protective shells, turtles also use several different kinds of vocal communication to coordinate their social behaviors - including one used by female turtles to call to their newly hatched offspring.

"These distinctive sounds made by turtles give us unique insights into their behavior, although we don't know what the sounds mean," Dr. Camila Ferrara said in a WCS press release. "The social behaviors of these reptiles are much more complex than previously thought."

Giant South American river turtles are known to navigate en masse during nesting season, behavior scientists speculate is facilitated by the turtles' sounds.

The research team captured 270 individual sounds made during 220 hours while the turtles were swimming through the Rio Trombetas between 2009 and 2011. Via analysis they were then about to categorize the sounds into six different types of vocalization.

Sounds made by the turtles while migrating through the river or basking tended to be low frequency sounds, possibly to facilitate contact between turtles over longer distances. Vocalizations made during nesting tended to be higher frequency sounds, possibly because higher frequency sounds travel better in shallow water and in the air.

But the highest diversity of sounds are used by females about to nest. The researchers theorize that the animals use these sounds to decide on a specific nesting site and to synchronize their movements.

And for the first time, researchers documented noises coming from the hatchlings themselves. The females, in turn, vocalize in response to the nestling calls, perhaps guiding the baby turtles into the water.

"Groundbreaking studies such as this one can help us better understand the complex relationships between both individual animals and their environment," added Dr. Julie Kunen, who was involved in the study. "Protecting the still sizable populations of Giant South American river turtles will also enable us to conserve the behavioral richness of these reptiles for future study."

The findings were published in the journal Herpetologica.