Dermal photoreceptors regulate basking behavior in the lizard Podarcis muralis.

There is evidence that dermal photic responsiveness can be found in a wide range of animals. Behavioral responses to dermal stimulation by light have been observed in pigeon squabs and new-born rats, and more recently in a sea snake. Here we report that painting the dorsal surface of the lizard (Podarcis muralis) with opaque black paint impairs the animal's ability to position itself beneath a light source containing negligible heat. Experiments using light of different spectra and intensities show that the effect is due to light of wavelengths shorter than 600 nm and of intensity higher than 2.5 mW cm-2. These experiments demonstrate for the first time that overt behavior in a terrestrial vertebrate can be mediated by a dermal light sense.