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
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| 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.
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| 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.
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| 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.
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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.
References
“How to train your Komodo dragon: Sunny the lizard wears
a GoPro camera as he runs towards targets at the zoo.”
“How to Train Your Komodo Dragon,” www.breakingnews.ie/discover/how-to-train-your-komodo-dragon-643293.html
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
