Spy turtles mating with 3D printed sex dolls

I am a turtle voyeur . I record the private life of turtles with hidden cameras and I've even got some spicy fragments up to the Internet. This peculiar inclination of mine is part of my work as a behavioral ecologist of quelonios.

I spy on the turtles to document and understand how they make more turtles. This may seem like a simple thing considering the slowness of the subjects, but to what extent is it difficult to spy on turtles? Well more difficult than it seems, but also more interesting. And thanks to cheap devices such as cameras and 3D printers, it is becoming cheaper and more fun.

In the documentaries and in the media, turtles are often shown doing one of two things: or lazily spending the summer days sunbathing on a log or painfully raffling cars to reach a safe place to bury their eggs . These behaviors are essential for the turtle baby manufacturing business and we already know a lot about them.

But what we know less about are the ins and outs of courtship and mating: what happens under the murky surface of lakes, rivers, ponds, swamps, marshes and other aquatic environments.

Cheap submersible cameras are improving the way we work. Animal ecologists have welcomed these toys because they allow them to take a look for a long time and only bother just their favorite study subjects.

The author of the study, with his turtle printed in 3D.

3D printing also opens up new and interesting ways for the study of animal behavior on the ground. Now we are able to produce, quickly and without much cost, animal-shaped lures with a realistic anatomy. We have started using these new tools to shed some light on the mating habits of the northern map turtle, which is on the list of endangered species in Canada.

The most surprising of the map turtles is the large difference in size between males and females. A large adult female can exceed three kilos, while a good-looking male will hopefully weigh 350 grams.

This asymmetry of sizes is the result of two facts. The first, that male map turtles do not fight each other, which is the key behavior that justifies corpulence in animals. And it is that in many species, when two males find a receptive female at the same time, things get ugly between them, if not the blood runs. Normally, the biggest male will be victorious and pass his big male genes to the next generation. But in the turtles map no. His tiny males are not altered by their rivals.

The second factor is the correlation between a mother's and her offspring's. Big mothers lay big eggs too. And from them big babies are born. These large babies are more likely to overcome the first days of life than small babies. That is why natural selection has favored large females.

Two adult turtles, in which the difference in sizes between the male (the smallest) and the female turtles can be seen. Grégory Bulté

That the males are aware of this or not is something we had to discover with our cameras and our 3D printed turtle dolls of various sizes. Our prediction was simple. If a normal male encounters many females of various sizes (as is the case with the peculiar hibernation habits of this species) and cannot mate with all of them, he will opt for the larger females.

Each fall the map turtles gather at specific points of lakes and rivers, and there they spend the winter, quietly, in the background. These hibernation zones also serve for mating. Turtles copulate when they arrive in these community places starting in the fall, and they take a little nap for five months (which looks like something like this).

And when spring finally comes, they mate again. Hundreds of turtles can gather in these community places, and that makes it inconceivable for many males that can mate with all the females present. For a short time, we found a handful of libidinous turtles concentrated in the same spot. And that is a dream come true for a behavioral ecologist of chelonians, like me.

To verify our predictions, we printed a female map turtle-shaped lure and placed them in pairs at two of those concentration points. These lures were totally identical in everything, except in their size. One was the average size of a female, and the second was slightly smaller than the largest female we have found in our population studies.

Then we mounted the unequal couple in a device in which we had also placed a camera, and submerged everything in the bottom of a lake early in the day to take it out at the end of the day. We repeat the operation over nine days, with two pairs of decoys.

The response of the wild males was clear: they preferred large females. Larger decoys received almost twice as many male visits and five times more mating attempts than small ones.

This video shows what a mating attempt is like (it plays fast and we've added musical accompaniment).

The cameras open a window to the private and underwater life of animals. Thanks to these devices and other technologies, such as 3D scanners and printers, we can check our hypotheses and predictions, or simply observe what animals do.

While we were analyzing the videos of our experiments, we saw several phenomena that we did not know, such as that of a female turtle that seemed to scream at one of the lures or a blackbird attacking a male lure. They may be just anecdotes right now, but they may give more of themselves.

The omnipresence and the low price of the cameras will undoubtedly give us many interesting observations about aquatic animals, turtles among them. And some may influence our way of conceiving animal behavior, and others simply do not give intriguing clues to a fairly unexplored world.

Grégory Bulté is an instructor, ecologist and evolutionary biologist at Carleton University