Finding reptiles
can be a challenge. In the 1970's Elizabeth and Charles Schwartz used Labrador Retrievers
to find Box Turtles on their study site in Missouri. Recent news stories report
researchers using a Labrador to find Indigo Snakes at the Nature Conservancy's
Apalachicola Bluffs and Ravines Preserve in Florida (Halley, 2010).
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| USDA Snake Detector Dog |
Now, Julie
Savidge and colleagues (2010) report that detector dogs have been used by the USDA since
1993 to inspect cargo leaving Guam that may contain Brown Treesnakes (Boiga
irregularis). In experimental trials dogs averaged 62% for snakes in
escape-proof containers planted in cargo without the knowledge of the dog's handlers.
Savidge et al. investigated if dogs could be used for finding Brown Treesnakes
in the wild on Guam as a way to ascertain if eradication efforts had been
successful. The snakes are primarily nocturnal and although humans can detect
them at night detection probabilities by humans is only 0.07 per search. During
the day, brown treesnakes are hidden making visual detection by humans
exceptionally difficult. However, trained dogs rely on odors and they may be
more successful at locating snakes. The researchers investigated canine teams
(dogs and their handlers) on Guam as a potential tool for finding Brown Treesnakes in the wild. Canine teams searched a 40 × 40 m forested area for a
snake that had consumed a dead mouse containing a radio-transmitter. To avoid
tainting the target or target area with human
scent, no snake was handled or closely approached prior to searches. Trials
were conducted during the morning when these nocturnal snakes were usually
hidden in refugia. A radiotracker knew the snake's location, but dog handlers
and search navigators did not. Of 85 trials conducted over four months, the two
canine teams had an average success rate of 35% of correctly defining an area
that was about 5 × 5 m that contained the snake with the transmitter; the team
with more experience prior to the trials had a success rate of 44% compared
with 26% for the less experienced team. Canine teams also found 11 shed skins
from wild snakes. Although dogs alerted outside the vicinity of snakes carrying
transmitters, only one wild, non-transmittered snake was found during the
trials. This article can be found on-line (see below).
Literature
Schwartz, C. W.
and E. R. Schwartz. 1974. The three-toed box turtle in central Missouri: its
population, home range, and movements. Terrestrial Series No. 5. Jefferson
City, MO: Missouri Department of Conservation. 28 p.
