New research emerging from Australia has given the scientific community and animal lovers alike a treat when it comes to the understanding of baby turtles’ behavior.
Using a small device called an accelerometer to study the movements of turtle hatchlings, researchers from Sydney’s University of New South Wales have discovered that unlike digging, as animal experts previously thought, baby turtles ‘swim’ up through the sand soon after hatching.
The reason why this behavior has been a mystery for so long? Well, baby turtles hatch out of nests that are buried deep under the sand, up to 80cm below the surface of the beach.
In the week after hatching, the baby turtles have to navigate their way through the sand in order to emerge at the surface before heading out to sea, as Davey Dor – a PhD candidate at the university – explains in a statement:
“When I visualise a hatchling that has just come out of its egg, it is completely in the dark in its surroundings. There’s no sign to point which way is up toward the surface – yet, they will orientate themselves and move upwards regardless. Our initial findings and ‘proof’ of this new methodology opens the door for so many new questions in sea turtle ecology.”
Over the last six decades, researchers have tested plenty of methods of trying to understand the first days in the life of turtle hatchlings, but human interactions – such as viewing the turtles through glass panes, and listening to them with microphones – limit understanding of the natural processes.
So, in their research – which was recently published in the academic journal Proceedings of the Royal Society: Biological Science – the Sydney-based research team decided to use the novel approach of accelerometers. These small devices measure changes in speed and direction and were thus able to help the scientists to understand the movements of the turtles.
After monitoring nesting sites at Heron Island, in the Great Barrier Reef, the researchers calculated the approximate dates at which the turtle eggs would hatch. Then – a cautious approach so as not to disturb the turtles’ natural behaviors or inhibit their welfare – the researchers sprung into action, as Dor describes:
“After locating the nests, we waited for approximately 60 days for the eggs to develop. Three days before they hatched, we put a device called a hatch detector next to 10 different nests. This unique instrument measures voltage at the nest site and lets us know when the hatchlings had hatched out of their eggs.
As soon as the eggs had hatched, [we] carefully dug down into the nest, selected the hatchling closest to the surface and attached a light-weight, miniature accelerometer onto the baby turtle, before placing it back. We then gently layered the sand back in the way it was found.
We checked the nest site every three hours and when they did finally emerge, we retrieved the accelerometer from the hatchling carrying it.”
With their behavior recorded, the hatchlings were then able to head on their journey for their life at sea.
Subsequently, the researchers were able to analyse the data from the hatchlings. By comparing the data from all ten baby turtles, they discovered that even though the turtles were buried under the sand in pitch darkness, they were able to sense which way to travel upwards.
Their movements, in an upward trajectory, were reminiscent of swimming motions and – though the turtles took infrequent rest breaks – once they became close to the surface they only moved at night time.
This suggests an innate understanding of the dangers that might lie at the surface for the hatchlings during the day, as well as an in-built method of sensing the direction toward the surface.
Why is this information important? Well, turtle populations are declining worldwide, so any information that may allow conservationists to help them – before the beautiful species is wiped out altogether – is vital.
Part of the reason that some species of sea turtle are endangered is because of their vulnerability at the nesting stage. While predators are one reason for this vulnerability, their susceptibility to nest destruction is only increasing due to climate change and the rising sea levels that it brings.
Thus, conservationists around the world sometimes relocate turtle nests, to give the eggs and their hatchlings the best chance of life.
However, this can cause problems with vital factors to the success of turtle nests hatchlings, as temperatures and moisture can be altered by the movement and new conditions; this may affect the hatch rate of the eggs, as well as the speed and movement capabilities of the hatchlings.
This vital research from the team in New South Wales provides more information about the behaviors of the hatchlings in their most vulnerable early days, that could be crucial to conservationists saving these adorable creatures.
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