Dogs primarily use color information over brightness to complete certain tasks, according to new research from Russian scientists. Despite having a much poorer color vision than humans, dogs rely on color signals to navigate their surroundings. The study, published in the Proceedings of the Royal Society B: Biological Sciences, found that under natural lighting conditions, color information could be superior for dogs. Dogs are dichromats, meaning they only have two types of cones that are sensitive to different spectral ranges. This is comparable to the vision of a red-green colorblind person. In contrast, humans are trichromats, possessing three types of cones that allow them to distinguish between red and green.
The researchers worked with eight dogs, teaching them to recognize which of two food boxes they could open using their nose or paw. The boxes were differentiated by color and brightness, with the dogs relying more on color than brightness to make their choice. Half of the dogs even exclusively used color information to make their decision. While previous studies have suggested that dogs use color for orientation, the extent to which they rely on it was previously unknown. The study suggests that color perception in dogs has been underestimated and could play a more significant role in their behavior than previously thought.
The findings also shed light on the visual abilities of other animals. Tetrachromats, such as many fish, birds, and turtles, possess four different types of cones, allowing them to perceive UV light. The study highlights the importance of color perception in animals with minimal photoreceptor equipment, which is necessary for color vision. While dogs may not have the same color vision as humans, they still rely on color information to navigate their environment.
