Short-term changes in dorsal reflectance for background matching in Ornate Tree Lizards (Urosaurus ornatus)

Some lizards are thought to exhibit short-term changes in color to match their background, but this ability has not been verified empirically. We tested the hypothesis that lizards will change dorsal reflectance over a series of days to match their backgrounds. We housed male and female Ornate Tree Lizards (Urosaurus ornatus) for five days in aquaria painted to match environmental extremes in substrate reflectance. Standardized photographs were taken each day yielding dorsal percent reflectance values. After the first day, reflectance of lizards changed significantly to more closely match their backgrounds; this effect became more pronounced through the fifth and final day of the experiment.