[Constancy of color perception in the gray toad (Bufo bufo L.)].

Colour vision and constancy of colour perception in Bufo bufo L, were examined by means of unconditioned reaction of choosing moving and stationary models of females by males during breeding season. The males chose blue and dark blue models. Control of the choice of blue models presented in pairs with models of different shades of grey proves the existence of colour vision in Bufo bufo L. The choice of blue models has been observed under significantly varying conditions: both with artificial illumination and in sunlight. This attests the capacity of toads for constant colour perception. When a model was presented against a saturated red background, colour contrast was observed: under such conditions the toads chose the grey models which evoked no reactions when presented against white background.