Dog cones can only detect 2 colors. No one is certain what those 2 colors are. Some experts think it could be blue and yellow. Alexandra Horowitz — author of "Being a Dog" — told us that it's ...

View Full Profile. Learn about our Editorial Policies. Humans rely on sight, which is primarily mediated by three color-sensing cone types, to perceive the world in a kaleidoscope of hues. Blue cones ...