This is a false statement dogs can see more than just black and white, while their sight color spectrum is limited they can see a collection of grey, brown, yellow, and blue. During the season they have limited sight colors because dogs only have 2 types of cones which is 20 percent of the cones human eyes have. With the 2 cones, they also struggle to see different hues of the same color. There is more information on this topic at the Purina online site.