Movie 1.

Comparison of source image with pit membrane image for 2 species. The source thermal image movie is on top with movies of the corresponding pit membrane images of C. atrox (middle) and T. albolabris (bottom). Color steps indicating 0.001^°C temperature changes on the membrane. The source images are of a mouse (Peromyscus spp.) in a woodlot in Vigo Co., IN, USA. The 60^° high x 80^° wide frames were reflected horizontally and suitably concatenated to create a 160^° wide scene. The mouse starts about 115 cm from the camera on the left and moves along a branch toward the thermal imager to a point within a striking range of 30 cm from the lens, then returns (backwards) to 115 cm. While motion improves detection at close distances, the consequences of aliasing and different optical spread functions are obvious even in overall background pattern. From (Bakken, G. S., Colayori, S. E. and Duong, T. (2012). Analytical methods for the geometric optics of thermal vision illustrated with four species of pitvipers. Journal of Experimental Biology 215, 2621–2629. Supplementary information Movie 2).