Fig. 1
From: Superior continuous quantity discrimination in a freshwater turtle
The experiment arena and quantitative stimuli. A The experiment arena was an acrylic tank (60 × 42 × 30 cm) filled with water to 15 cm depth. We mounted a GoPro (CHDHB-601) to the back wall of the tank and a JVC camcorder (GZ-E10BU) on a tripod next to the tank. B We used wooden cubes (1.5 × 1.5 × 1 cm) colored with red acrylic paints (Mona, SG-203) on a white Velcro board (11 × 11 cm) as the quantitative stimuli. C Each turtle was trained to swim toward the stimuli and was rewarded with a food pellet when it reached the designated area (the square marked with blue stripes) for the correct (larger) quantity