[Animals] This surprising discovery turns everything we knew about turtles upside down.

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This surprising discovery turns everything we knew about turtles upside down.
An unexpected observation about one of the rarest turtles on Earth reveals that cold-blooded reptiles may have more complex social bonds than we thought.

Paddling a canoe down a murky Belizean river at dawn, Don McKnight and Jaren Serano heard the sound of the Central American river turtle, known locally as the hicatee.

A hydrophone placed in the water detected the movements of the reptiles, which had sonic transmitters attached to their shells.

The results surprised them: the turtles swam together through the river and, in some cases, they did not separate themselves even a meter from their peers. "It was like following a group of whales," says McKnight, an ecologist at LaTrobe University in Australia and the Turtle Ecology Laboratory in Belize.

These social turtles could dramatically change how we think of supposedly solitary animals, he says. It was previously thought that turtles gathered together when searching for the same resource, such as a sunny rock, but they generally did not interact with each other.

In the recent research, however, the turtles seemed to be looking for company. "It was very nice to see," says Serano, a master's student in the Department of Wildlife Ecology and Conservation at the University of Florida (United States).

What's more, the scientists' study, published this week in the journal Animal Behavior, may help conservationists protect this critically endangered species, which has declined throughout its range of Belize, Mexico and Guatemala. There are no solid po[CENSORED]tion estimates for this highly poached reptile, but its number could be as low as 10,000.

Hicatees are often sold on the black market for their meat, considered a delicacy in Central America.

"Belize remains the last bastion of the species, although if poaching continues for meat and eggs beyond domestic consumption, [it could become extinct] within the next 30 years," says Venetia S. Briggs-Gonzalez, an ecologist specializing in wildlife from the University of Florida that is not involved in the research.

(Related: We thought we knew everything about turtles; until today)

Random or social?
McKnight and Serano were conducting other research on hicateos in the spring of 2020 when they discovered that the animals move in unison.

"It's one of those random, silly ways that happens sometimes in science," McKnight says.

To find out if the turtles were actually socializing, the team found a section of the river that did not have any of the known variables that could attract turtles, such as logs, rocks or vegetation. By placing sonic transmitters on the shells of 19 juveniles of both sexes, the team was also able to rule out mating behavior.

The scientists then followed the tagged turtles daily from a canoe for a few months, going up and down the river and measuring groups of two or more turtles, which revealed the distances between individuals.

It was not easy. One day, the couple came across a crocodile skirting the canoe. During a heavy downpour, they had to interrupt their work to bail water out of the boat.

Once the data was obtained, McKnight, Serano and their colleagues ran simulations to determine whether the turtles' groupings and travel habits were random or evidenced sociality. The random model showed that the distances between the turtles were always greater than in nature.

This means that real-life turtles did not move randomly, but rather flocked together on purpose, in groups of varying sizes.

(Related: They discover a new species of turtle that is 205 million years old)

An underappreciated social life
"There are probably a lot more social behaviors than we've been able to document," says McKnight, who hopes his study will inspire more research on social reptiles, since these cold-blooded animals have been forgotten in favor of mammals and birds.

"The results will surprise some, but not those of us who have studied the social behavior of turtles," says J. Sean Doody, associate professor of Conservation Biology at the University of South Florida (United States), in an email. . He adds that he has observed similar behavior in hognose turtles in tropical Australia, but has not yet documented it scientifically.

Doody, who was not involved in the research, says it "dares to consider that turtles, ancient reptiles that predate humans by hundreds of millions of years, may have complex social lives outside of courtship and mating or fighting." .

Briggs-Gonzales adds: "There is much more to social behavior in the animal kingdom than we can understand."

(Related: This is Chonkosaurus, the most famous giant turtle on the internet)

A boost for conservation?
It's also unclear why turtles group together, although it may be to protect themselves from predatory crocodiles, McKnight says.

And although crocodiles are less likely to attack a group of turtles, poachers prefer it.

"The strategy they have developed for most predators, and which has worked very well, backfires when it comes to humans," says McKnight. "We've always heard reports of poachers catching dozens of turtles in one night, which we found very difficult to understand," McKnight says.

According to Day Ligon, co-author of the study and professor of biology at Missouri State University (United States), this finding could also prompt the review of current laws in Belize, such as the prohibition of the use of gill nets, which can trap large groups of turtles at the same time.

These efforts could prevent another tragic extinction, experts agree.

"We don't want to lose this species like we lost others that are grouped together," says Doody, "for example the passenger pigeon, which became extinct more than 100 years ago."

https://www.nationalgeographic.es/animales/2023/09/sorprendente-descubrimiento-pone-patas-arriba-conocimientos-tortugas