Stimulus modality lit area, the eyes require time for a good quantity of rhodopsin to regenerate. As more time passes, there is a higher chance that the photons will split an unbleached photopigment because the rate of regeneration will have surpassed the rate of bleaching. This is called adaptation. Humans are able to see an array of colours because light in the visible spectrum is made up of different wavelengths (from 380 to 760 nm). Our ability to see in colour is due to three different cone cells in the retina, containing three different photopigments. The three cones are each specialized to
Three-spined stickleback then a stickleback's condition-factor (i.e. its ability to flee) determines how closely it approaches the predator rather than the stickleback's size. Both the strategy and reaction to different-sized partners seem to be dependent on whether the partner cooperates or defects. Sticklebacks have four colour photoreceptor cells in their retina, making them potentially tetrachromatic. They are capable of perceiving ultraviolet wavelengths of light invisible to the human eye and use such wavelengths in their normal behavioural repertoire. The three-spined stickleback is a known intermediate host for the hermaphroditic parasite "Schistocephalus solidus", a tapeworm of fish and fish-eating birds. Three-spined sticklebacks have