SWS2
One of 5 classes of visual Opsins in vertebrates, to which humans possess none. They are present in most birds, fish and reptiles. In mammals, they are present only in monotremes (e.g. Platypus). The peak wavelengths in this class range from 415-480nm and are therefore sometimes referred to as ‘blue’ cones, though they are unrelated to humans’ ‘blue’ cone (S-cone), which instead belong to the SWS1 class (‘UV/Violet’).