Tuesday, October 21, 2014


On one recent morning two attentive turtles, including Diode, the eastern box turtle matriarch of the lab, were watching an online video from my hands. I’d blown it up to the full size of the monitor, and several other turtles with good sight lines were oriented toward it, too. A nine-foot-long
Sunny with his GoPro camera.
Komodo dragon (Varanus komodoensis) was lumbering toward a yellow circle on the end of a stick held by a San Diego Zoo keeper. In his other hand, hidden behind him, the keeper held a red grabber holding a fish. The dragon, Sunny, touched the yellow circle with his nose, then turned toward the side where the treat usually appeared. When it did, he grabbed it, and it was gone in a flash.
Sunny hits the target.
               In a video on the second site, below, note that the treat and the yellow disc are both held in front of the trainer, apparently at a later stage of training. Sunny still touched the yellow disc before grabbing the reward. The video showed Sunny repeating the task several times.

               During one repetition, Diode pushed on my hand—hard—toward the computer monitor.
Recreation of Diode approaching the target on the computer monitor
She tapped the yellow disc, then steered to the kitchen and tapped the refrigerator.
       I was surprised but got the point. I opened the fridge door and fetched her a night crawler. She ate it nearly as fast as the Komodo dragon. Tapping the refrigerator directly would have cued me that she wanted to eat, but she showed she could play the target game, too. Did she see the game as yet another way to control me—not the other way around?

Bingo! Diode recreates tapping the target.

       I find the work with this largest species of monitor lizard fascinating. Though the training relies on no more than a Pavlovian association (like Pavlov’s dogs salivating at the bell), it shows that even a huge and very dangerous lizard* can be trained so that he can be maneuvered for veterinary work and other purposes, and it demonstrates a level of brainwork that’s of interest to scientists working in comparative cognition. There are benefits for the dragon as well. Working for food has been shown to be a valuable enrichment for confined animals. Using the mind is one benefit; exercise is another. Otherwise, there isn’t much motivation to run in a zoo enclosure. For all of these reasons, Komodo dragons have been trained in other zoos, including London Zoo and the National Zoological Gardens in South Africa (link below with training how-to information, but don’t try this at home—with a Komodo dragon, that is).

               Diode, as you see in these recreations for the camera, did try it at home—though not my idea. Diode has not been trained to get food by tapping a yellow disc—or any other way. She imitated the dragon’s successful target tap on the second time she saw the video. She steered to the screen in my right hand as I held the camera in the left (not too easy in real time). Some shots missed entirely, but two (above) caught the action.
Diode approaches a virtual nose bump with Sunny,
again a photo with a live, moving Diode and the video.
No animals have been injured in these photographs.
        Readers, I’d love to hear your comments.



“How to train your Komodo dragon: Sunny the lizard wears a GoPro camera as he runs towards targets at the zoo.”
Training Komodo dragons at the National Zoological Gardens in South Africa: www.nzg.ac.za/newsletter/issues/19/01.php

*Notice the cautious length of the sticks; even if a bitten deer or other prey escapes, the Komodo dragon bite can kill from “a sophisticated combined-arsenal killing apparatus,” primarily their venom, which affects blood coagulation and induces shock. Venom now appears to be more important for the kill than toxic bacteria.
Bryan G. Fry et al. A central role for venom in predation by Varanus komodoensis (Komodo Dragon) and the extinct giant Varanus (Megalania) priscus. PNAS June 2, 2009, vol. 106 no. 22, pp. 8969-8974. http://www.pnas.org/content/106/22/8969.full