Training dogs to detect invasive alien species in Japan: Discrimination of reptile odor

Abstract

The use of dogs for detecting invasive animal species has increased in Japan. Damage to endemic species by the Carolina anole (Anolis carolinensis) is expanding in the Ogasawara Islands. We hypothesized that dogs trained to recognize the anole's odor would be useful in detection work. A healthy adult female German shepherd was trained to discriminate anole odors by using a cloth onto which we had transferred frozen body odor or frozen excrement/urine odor, along with an odorless cloth. After achieving 100% accuracy, she was trained to discriminate between body odor and excrement/urine odor of the same anole. Then the dog was trained in a three-way test to discriminate among native Ogasawara reptiles and the anole. The dog achieved 100% accuracy in training for body odor in 27 sessions over 14 days and for excrement/urine odor in 4 sessions over 2 days. The mean correct search time differed significantly between odors in training (P < 0.05), but not in the discrimination test (P = 0.71). The rates of the correct response in the two-way discrimination test were high (body odor, 90%; excrement/urine odor, 96%). Correction rate in the three-way test was >90%. Discrimination between transferred odor and the odorless sample in training was relatively easy. However, discrimination between odors of the same anole and between odors of the native reptiles and the Carolina anole was harder.