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To get a sneak peek into the sex lives of some shy turtles, a team of researchers has developed the ultimate tool for covert ecological research: 3D-printed sex dolls.
Ecologists at Carleton University in Ontario have been using turtle sex dolls – or, scientifically speaking, “3D-printed animal decoys” – to study northern map turtles (Graptemys geographica).
While the turtle is not endangered nor threatened in Ontario, it’s listed as a “special concern” by the state’s environmental authorities because it's vulnerable to ecological changes and facing increasing threats. As such, understanding its reproductive behavior could be key to its future survival.
Unfortunately, the species is a pain to study for a number of reasons. First of all, they dive into the water at the slightest hint of a threat. They also breed in the murky depths of freshwater lakes and rivers, so catching a glimpse of their mating behavior can be tough. While searching for a way to get around this hurdle, the turtle researchers came across other scientists using 3D-printed animal decoys to sneakily study their subjects.
"The inspiration came from many springs spent snorkeling at the sites where map turtles overwinter in Lake Opinicon," Grégory Bulté, an Ecology and Evolutionary Biology instructor at Carleton University, told IFLScience.
"I would often see males courting females or following them around. Being interested in understanding their mating behaviour, I just wondered if we could fool the males with realistic females models. I first tried with a Go-Pro I borrowed from a friend and an old map turtle carapace [shell] someone gave me. It worked. Males came to check it out so we started looking into making decoys using our 3D printer."
In one of their studies, published in April 2018, they set out to see whether male northern map turtles care about the size of their female mate. This species is an example of sexual dimorphism, with the females being considerably chunkier than the males.
Using a scan of a dried turtle specimen, the team 3D-printed several realistic female turtle decoys in two sizes, 21 centimeters and 25 centimeters (8.3 and 9.8 inches). They then armed the “sex dolls” with a Go-Pro camera, dumped them in a suitable body of water during mating season, and watched the sparks fly (as you can see in the video above).
The findings showed that the males were notably more interested in the larger lady turtle. This is essentially what the researchers expected: larger mates lay larger eggs, and larger hatchlings mean a greater chance of survival. However, the video footage also picked up on some unexpected behavior from the pond’s inhabitants.
“As we were sifting through videos from our experiments, we witnessed a number of phenomena we did not know were possible, including a female map turtle seemingly squeaking at a female decoy and a loon attacking a male decoy. These may just be anecdotes for now, but perhaps there is more to them,” Bulté wrote in a recent article for The Conversation.
“The ubiquity and affordability of action cameras will surely yield many insightful observations about aquatic animals including turtles. Some may influence how we think about animal behavior, others may just be intriguing tidbits of a world largely unexplored.”
