The hawks seeing ultraviolet Have a very fourth cone sort, although quite a few mammals only have two styles of cone, as their eyes are dominated by colour-insensitive rod cells, essential for night vision. It's because mammals had been originally nocturnal. John LawlerJohn Lawler 109k1111 gold badges185185 silver badges489489 https://dean45c21.blogsuperapp.com/37118236/gifts-options