A Novel Form of Behavioral Camouflage in Colubrid Snakes

Different types of animal camouflage ultimately have one function: avoiding detection. The most common form of camouflage, background matching, involves color patterns that match the surrounding environment while the individual remains motionless. However, in a dynamic environment, movement could also contribute to camouflage. For example, reverse crypsis or motion dazzle employs color patterns that can disrupt the pattern of motion to aid in concealing an individual, or by making it more difficult to track the individual's movements. Here I describe a new form of behavioral camouflage in colubrid snakes. The behavior consists of a series of small, laterally oscillating movements. Observed in three colubrids (Thamnophis sirtalis, Thamnophis sauritus, Opheodrys vernalis), I hypothesize that this behavior serves to blend the dorsal patterning of a snake with moving vegetation. Through 73 observations in T. sirtalis, the head-wobble was only observed being performed by small snakes in grassy/reedy areas while the wind was active. In the case of both species of Thamnophis, this may match the movement of grass in the wind with the dorsal stripe on the snake, and help a snake avoid potential predators.