The phone buzzed as the tracker came online, and a little circular blip appeared on the map. Helen Pheasey watched the dot intently as it moved inland from a beach on Costa Rica's Pacific coast.
"It just kept moving," she says. "Every hour I'm checking, and it's gone further and further."Pheasey, then a PhD student at the Durrell Institute of Conservation and Ecology in the UK, was tracking a stolen item -- but not the usual type.
The dot was tracking the journey of a fake turtle egg, which Pheasey had planted deep within a real turtle nest the day before. The egg was poached and trafficked to a supermarket loading bay 137 kilometers (85 miles) away, where it was probably sold.
Dubbed an "InvestEGGator," the fake turtle egg -- roughly the size of a ping pong ball -- was developed by scientists at US-based conservation organization Paso Pacifico, which focuses on protecting coastal ecosystems in Central America.
Made of a rubbery material called NinjaFlex, the fake eggs are daubed with a special textured paint -- developed by Hollywood special effects artist Lauren Wilde -- that gives off a yellowish tinge.
The fake eggs look and feel like the real thing, but hidden inside them is a SIM card with a GPS transmitter that uses mobile networks to transfer location data, and a USB port for charging.
Paso Pacifico developed the decoys as a tool to combat trafficking. The organization estimates that poachers destroy more than 90% of sea turtle nests on many of Central America's unprotected beaches, to sell the eggs into the illegal wildlife trade.In a two-year research project that began in 2017, Pheasey deployed 101 fake eggs in the nests of olive ridley and green sea turtles across four beaches in Costa Rica, to test their effectiveness in tracking trade routes.
The results of her study, published this year, show that the devices could help to crack the illegal wildlife trade not just in turtles, but across a number of vulnerable species.
Planting the fake eggs
Pheasey and her team planted the decoys during the night, once the turtles had dug their nests and scurried back to sea. With just one fake egg hidden within a clutch of more than 100 eggs, she hoped they wouldn't be detected by poachers.
If the fake eggs were taken from the nests, the SIM card would find a signal and send an alert with GPS coordinates to Pheasey.
"It's just like your mobile phone," she tells CNN. "If you bury your phone in the sand, you're not going to have any signal. But as soon as they're uncovered, they'll come online."
Of the 101 decoy eggs deployed, a quarter were illegally taken and five successfully provided tracks.
The tracks varied in length. One decoy traveled under 50 meters (160 feet) to the nearest beach house, one moved two kilometers (just over a mile) to the nearest bar, while another went 137 kilometers (85 miles) inland, providing solid evidence of the turtle egg trade.
In some cases, decoys' journeys revealed the full trade chain: from the poacher, to a seller, to a customer's residence, says Pheasey.
Policing illegal trade
This intelligence could help strengthen law enforcement by enabling authorities to target traffickers and criminal networks rather than local poachers, who are usually "marginalized individuals trying to make a quick buck," says Pheasey.
While turtle eggs have been eaten by coastal communities for centuries, the rise in demand in towns and cities across the world -- combined with other growing threats to turtles such as overfishing and net entanglement -- makes this practice unsustainable, says Sarah Otterstrom, conservation scientist and executive director of Paso Pacifico.
"They're now considered a delicacy and an aphrodisiac," she tells CNN. "In many bars and restaurants, people will make turtle egg soup, or they'll put a raw turtle egg in a drink."
As more turtle populations decline, protection of their eggs is crucial to ensure their survival.
However, before the decoy eggs can be used effectively for conservation and law enforcement some hurdles remain. Paso Pacifico are working to extend the eggs' battery life, which only lasts for a few days when the eggs are sending hourly location alerts.
Pheasey identified low signal reception in coastal areas as another possible limitation, but Otterstrom doesn't see this as a major problem. "Even though there might be beaches that are remote and don't have cell phone technology, as the eggs make their way towards markets, they will inevitably come across cell phone towers," she says.
What's important is that the tracking technology is affordable, widely available, and works in most countries around the world, so it can be used to identify cross-border trade, she says.
Paso Pacifico has sold its turtle egg decoys, at around $60 an egg, to conservation projects and law enforcement agencies, including one undisclosed South American government.
Otterstrom says that Paso Pacifico is planning to adapt the technology to work for other species whose eggs are vulnerable to illegal trade, such as parrots or crocodiles.
The organization is working with a group in Ecuador to combat the gruesome shark finning practice by developing tracking devices that could be embedded in the fins of sharks caught as bycatch and sold legally. This would help to reveal international trade routes, says Otterstrom.
With the global illegal wildlife trade estimated to be worth up to $23 billion dollars annually, decoy tracking technology is a tool with great potential.
"Intelligence is key to prevention," says Pheasey. "It means that you're always ahead of the poachers rather than behind. We need to be proactive, not reactive."