Nonvisual responses to light, such as entrainment of the circadian clock, involve trinsically light-sensitive melanopsin-expressing ganglion cells as well as rod and cone toreceptors. However, previous studies been unable to demonstrate aspecific contribution of cones in the photic control of responses to light. Using a mouse model specifically lacks mid-wavelength (MW) we show that these photoreceptors; icant role in light entrainment and in phase ing of the circadian oscillator. The of MW cones is mainly observed for light sures of short duration and toward the wavelength region of the spectrum, with the known properties of this opsin. Modeling the contributions of the various tors stresses the importance of the particular spectral, temporal, and response domains of the photopigments assessing their role and contribution in than responses to light.