How to Count Komodo Dragons

Komodo dragon and a critter cam. Note the hanging goat meat. (You could make a mean birria with that chunk.)

If I know one thing about komodo dragons, it is: you cannot ride a komodo dragon, no matter how much you'd like to.

If I know two things about komodo dragons, they are: you cannot ride a komodo dragon and that they are endangered in their native Indonesian-island habitats.

Because of the latter consideration, biologists want to be able to monitor the population of these top-of-the-food-chain predators, who kill with strong jaws and nasty venom. In the past, scientists tended to trap them in long metal cages baited with chunks of goat meat. Then they'd check the traps to get a rough count of how many dragons lived in a given area.

But that's expensive, time-consuming, and at least in some places, the dragons have wised up to the idea that the dragon-sized metal box with goat meat inside is a trap.

If you look closely, you can see the scientists have written, "Not a trap," on the side.

So, an Italian-Australian-Indonesian team of researchers turned to a slightly less hands-on approach: the critter cam, in this case an off-the-shelf ScoutGuard 560V. They reported their results in a new paper in PLOS One.

They set out to address two key questions: 1) could these motion-detecting cameras, which use infrared sensors to detect heat, work with cold-blooded animals? 2) were the camera-based animal detections comparable to the data that could be obtained with traps?

In both cases, the researchers found positive results. The motion-detectors successfully detected the large lizards, despite not being warm-blooded like cuddly mammals. And they could model the relationship between trap detections and camera detections with some certainty. 

That's good news for conservationists struggling to protect these animals with little humanpower and less money.

"Firstly, moving to a camera-only method would considerably reduce time and labour costs and hence financial costs currently spent on trap-based Komodo dragon monitoring," the authors write. "Secondly, resource limitations have severely hampered managers of Komodo National Park in undertaking robust monitoring to census the status of Komodo dragon populations. Assuming provision of cameras, such a method could be employed within their existing funding to better enable them to conduct independent monitoring."

Via Scientific American

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