Fake Egg Gives Baby Sea Turtles a Better Crack at Survival
The University of Virginia, in collaboration with Nerds Without Borders, reported some egg-citing news Wednesday in the scientific journal PLOS One.
Nerds – a collection of volunteer engineers using off-the-shelf technology – created a fake egg to monitor the hatching of endangered baby sea turtles.
Erin Clabough, an associate professor of psychology, got involved with Nerds Without Borders during a fateful walk on the beach with her dog. (Photo by Erin Edgerton, University Communications)
UVA research has now shown that the device can reliably predict hatching times to the day. The breakthrough promises to reduce the waiting of both conservationists and those who wish to use cordoned-off portions of the beach.
“This is something that helps not only the turtles, but a bunch of people,” said lead author Erin Clabough, an associate professor in the UVA Department of Psychology who teaches research methods and neurobiology courses.
The research was performed in collaboration with the National Park Service, which has gotten heat from the public in years past because of beach closures. Now, the service can more tightly predict when barriers need to be expanded and a host of other concerns related to hatching.
Sea turtles, such as the loggerheads of North Carolina’s Cape Hatteras National Seashore, which the study primarily focused on, are federally protected. Conservationists want to ensure that the turtle tykes, which usually emerge at night, scramble to the safety of the ocean after they’ve hatched. The draw of artificial lights from residences, or even a bonfire, could send their akimbo legs in the wrong direction.
Enter the humans who help guide them.
Unfortunately, the volunteer babysitting has historically been less than precise. Watchers have had to observe the nest being laid, then count forward in time to come up with a window for hatching, which could be one to two weeks wide.
Although Hatteras Island has worked to improve its restrictions in recent years, “Park Service protocols call for nest expansions, with associated beach closures, on a certain date after the nest is laid,” Clabough said. “It is not based on when the turtles actually hatch beneath the sand.”
The volunteer efforts become more active with the appearance of a depression in the sand – only sometimes an indicator that hatching has started – or the actual emergence of turtles.
The lingo for just a few turtles appearing, by the way, is a “trickle.” When the whole squad toddles out together, it’s a “boil.”
From Hatched Scheme to Scientific Study
Loggerheads, scientifically known as Caretta caretta, have an amazing innate ability to coordinate their first steps. More often than not, the hatchlings leave the nest in packs, and at night. The survival strategies of safety in numbers against predatory ghost crabs, and safety at night against ravenous coastal birds, have long been noted.
But scientists have been less certain about how the underground teamwork comes together, according to the researchers’ paper, “The Secret Life of Baby Turtles.”
Nerds Without Borders decided to create an egg with a motion detector, known as an accelerometer, to learn more. The innovators included Nerds founder David Hermeyer, IBM master inventor Thomas Zimmerman and retired engineer Samuel Wantman, until recently affiliated with North Carolina State University. The research also benefited from the work of undergraduate biology major Joshua Chamberlin of Hampton-Sydney College and the nonprofit Hatteras Island Ocean Center – the hub for volunteer efforts on Hatteras.
The collaborators called their nerdy scheme “TurtleSense.”
Though the technology and its installation methods have been ever-evolving, the process generally works like this:
Removing about 10 eggs from each nest, volunteers insert the fake egg – a ping-pong ball with a microchip inside. They then return the real eggs to the pile and cover it back over. The imposter egg is attached to a cable, which volunteers bury in a trench encircling the nest. The cable extends out of the ground at one corner to a transmitter in the dunes. Any motion that is eventually detected is sent as packets of information to software monitoring the situation, creating a profile of the energy coming from the nest.
The team established its proof of concept in 2013. Clabough got involved in the project in 2015 while summering on Hatteras.
“I went on a walk with my dog, and we were near a turtle nest being staked out,” she said. “I met another person walking his dog who said he was from Charlottesville.”
The man turned out to be Eric Kaplan, an entrepreneur and the founder of the Ocean Center.
“I said, ‘You all need a scientist who does something in biology to perform a peer-reviewed measurable study,’” she recalled. “They had prototypes and were testing them. So when I came on, we decided to do a more rigorous, controlled study. We wanted to see if we could predict when the hatching would happen and how tightly we could get it. It kind of became my passion project.”
The team embedded the fake eggs in numerous nests managed under National Park Service protocols over the next five years. Ultimately, 74 nests met the strict conditions for inclusion in the study.
‘The Secret Life of Baby Turtles’
The researchers found that their readings for the first 40 days of incubation were virtually indistinguishable from background noise. After that time, though, things would get interesting.
In the final week or two of incubation, the subtle activity would more clearly evidence itself. Then, there would often be a new low in activity – the prehatch phase – before a burst. As the turtles broke free from their shells, they would scramble past the sensor.
The researchers were accurately able to monitor both the beginning and end of hatching activity, which occurs in undulations over a period of about two days. During approximately another day and a half, the turtles would go mum again, as they awaited their moment to rise.
“We’ve known there is incubation, and we’ve known they all hatch and gather en masse,” Clabough said. “Sometimes there’s a trickle. But what’s really interesting in what we detected is that hatching activity tends to happen in these waves; then they’ll all kind of settle down. Our interpretation of this is there might be some vibration or movement cue for them to coordinate.”
But if vibration helps the turtles know when to hatch, how do they know when to leave their sandy burrow?
“There are theories in the literature that they’re waiting for temperate changes when its cooler, which would usually be a night,” she said.
For the purposes of conservation management, the sensors notably helped rule out infertile nests while warning against predation and tidal surges due to storms. The volunteers were also able to wait 40 days after a nest was laid to move the communication towers into place, since nothing much could be detected before then, allowing volunteers to do more with less equipment.
Most importantly, though, the research demonstrated that barrier erection and turtle-sitting could be “just-in-time” processes, the paper states.
If nest depth is known, the technology can predict turtle emergence to the day.
“That’s pretty amazing because the protocol down there is a much bigger window,” said Clabough, who both helped install sensors and performed turtle vigils.
Currently, volunteers work in pairs for up to eight days – about five hours each night – in anticipation of the new arrivals.
The labor isn’t really free, either. North Carolina spends about $2 million a year to support the training and deployment of about 600,000 volunteers statewide. A more targeted approach to both people and resources could save money.
Left, Erin Clabough installs the TurtleSense system in a freshly laid loggerhead nest. Right, volunteers work on other installations. (Photos by Elsa Clabough and Erin Clabough)
Natural Curiosity and Getting Involved
As a developmental neuroscientist, Clabough said it was fascinating to think about how the turtle babies accomplish the collective feat.
Working on the project was also a way she could spend additional time with her own offspring.
“Being a mom, too, with my four kids, they were all involved on this project,” she said. “They were the youngest turtle-nest watchers the Park Service had ever had. Now, they’re 12, 14, 16 and 18. But if you backtrack seven years, they were all elementary and middle school age then.”
Clabough noted that another exciting possibility for the future of TurtleSense is ecotourism. She said she had never witnessed the adorable dash to the water before she got involved with the project, and she thinks others would enjoy being able to plan their vacations to include a sighting.
“It’s one of the most magical things I’ve ever seen to watch little baby turtles pop their heads out and make their way to the ocean,” she said. “I feel like in some ways it’s a transformative experience. All the sudden you get why it’s important, why we need to protect. You feel grateful to have witnessed that.”
The technology’s potential, of course, is not just limited to uniting beach-users and conservationists on Hatteras. Sea turtle populations are declining worldwide. Green, hawksbill, Kemp’s ridley, leatherback and olive ridley sea turtles all have joined loggerheads on the threatened or endangered list.
When the researchers also monitored green sea turtles on Hatteras and olive ridleys in Costa Rica, TurtleSense recorded similar patterns to the loggerheads. Clabough said that suggests that the technology works regardless of sea turtle species or setting.
TurtleSense is available as open-source plans and software. The researchers said the average setup costs $300 ($50 to create the sensor and $250 to build the tower).
“We’re happy to serve as consultants for anyone who would like to implement the system wherever they are,” Clabough said.