STUDY DESIGN

The overarching objective of Dr. Cablk’s study focused on assessing the efficacy and reliability of wildlife detection dogs to locate only live desert tortoises—not scat or carcasses—on the surface and in burrows under natural but controlled desert conditions. Reliability is defined as the number of times a dog encounters a tortoise and responds with its trained alert to indicate that a find was made. The trained alert is a behavior, such as sitting or lying down, that the dog performs to communicate to the handler when the target—in this case, a desert tortoise—is located. Reliability is not a measure of a dog’s ability to find tortoises; rather, it is a measure of the dog’s usefulness as a survey tool.

Data-gathering aspects of this study began with initial scent-recognition training for the dogs, conducted in Montana by WDC dog handlers. Dogs were trained on residual scent—scent that can be captured and remains on a surface even though the original source has been removed. Tortoise scent was captured by wiping sterile gauze pads only over the living, shedding parts of the front portion of the tortoise, including the soft skin of the front legs, armpits, neck, and face. Upper and lower shells or hindquarters were not used in preparing training aids to avoid incorporating the scent of scat. The gauze pads containing the residual tortoise scent—or target scent—are referred to as training aids. Blank training aids—gauze pads from the same box that contained no tortoise scent—were also prepared. Presenting the dogs with blank training aids as well as tortoise training aids helped teach the dogs it was tortoise scent and not gauze that the handlers wanted the dogs to find.

Following the initial phase of scent-recognition training, the dogs were transported to the DTCC in Las Vegas, Nevada. There they spent several days becoming acclimated to the dry desert air and myriad of different smells, as well as being introduced to live tortoises. The final data-gathering tasks centered on the research trials conducted at the DTCC to evaluate the effectiveness of canines to serve as survey tools and ultimately aid in the recovery of Mojave Desert tortoise populations.