Color vision in sika deer (Cervus nippon): are certain colors used in electric fences difficult for sika deer to distinguish in grasslands?

Abstract

This study aimed to obtain basic knowledge to improve the effectiveness of electric fences in preventing sika deer (Cervus nippon) from invading grasslands. We used behavioral techniques to determine whether certain colors used in electric fences are difficult to distinguish from that of cool-season forage grass (Italian ryegrass Lolium multiflorum Lam.). In an operant conditioning room (4 × 8 m), a pair of colored panels (0.4 × 0.3 m) was presented to each captive sika deer (one male and one female) per session. Green-yellow was used as the positive stimulus and purple, purple-blue, blue, blue-green, green, yellow, yellow-red, red, or red-purple were negative stimuli. Each session consisted of 15 trials for the male and 20 trials for the female. The criterion for successful discrimination was to achieve a minimum of 80% correct choices for the male and 75% for the female sika deer out of the total trials for three consecutive sessions (P < 0.05, Chi-square test) by the 20^th session. Both male and female sika deer could discriminate between green-yellow and the other colors, except yellow. These results indicate that certain wire colors are difficult for sika deer to distinguish when an electric fence is installed in grasslands.

Journal of Warm Regional Society of Animal Science, Japan 67 （2）: 73-82, 2024