What colors do dogs see at night?

When night falls on the earth, human vision is gradually blurred by darkness, but our loyal canine companions are still active. What does the world look like to dogs on those moonlit or starlit nights? Can they distinguish colors like during the day, or will they fall into darkness? With curiosity about these questions and deep care for dogs, we embarked on a journey to explore the mysteries of dogs' night vision and try to uncover the mysterious colors in their eyes. ​

To understand the colors that dogs see at night, we must first delve into their unique visual system. Compared with humans, the structure of dogs' eyes is significantly different in adapting to changes in light. In the human eye, there are two important photoreceptor cells distributed on the retina - cones and rods. Cones are mainly responsible for distinguishing colors and seeing objects in bright environments. Humans have three different types of cones that can perceive the three primary colors of red, green, and blue, and form a rich and diverse color vision through combination. Dogs have fewer types of cones, only two, which can perceive blue and yellow spectra. Red and green are often confused in dog vision and cannot be clearly distinguished like humans. ​

Rods play a key role in night vision. Dogs have far more rods than humans, which gives them better vision in low-light environments. Rods are extremely sensitive to light and can capture slight changes in light, but they cannot distinguish colors. Their main function is to perceive the outline and movement of objects. In dim light, although the world in the eyes of dogs is not as colorful as during the day, they can use a large number of rods to detect subtle movements that are difficult for humans to detect, such as the slight movement of mice in the grass or the swaying of human figures in the distance. ​

When night falls and the moonlight shines on the earth, the world in the eyes of dogs will present a unique combination of colors. Because they can perceive blue and yellow spectra, the night sky may be a deep blue in the eyes of dogs, and objects with cool tones under the moonlight will appear more vivid. White or light grey objects may appear lightly blue in the light of night, while yellow objects, such as withered leaves, can still attract dogs' attention even in weak light. Nights that seem gray and monotonous to humans have different color levels and light and dark contrasts in the eyes of dogs. ​Interestingly, dogs' perception of color is also affected by the intensity of ambient light and the reflective properties of objects. Under street lights, the light is relatively bright, and dogs have a slightly stronger ability to distinguish colors, and can more clearly distinguish blue and yellow objects. In a completely dark environment, with only weak illumination from starlight or moonlight, dogs' vision will rely more on rod cells. At this time, the world in their eyes almost loses color, leaving only different degrees of light and dark changes, just like humans watching black and white movies. But even so, dogs can still move freely in the dark and explore their surroundings with their keen vision and excellent motion perception. ​

Imagine that when we take a dog for a walk at night, it suddenly stops and stares at a certain direction intently. Maybe in our eyes, there is just a blurry black shadow, but in the eyes of dogs, it may be an interesting target flashing with unique colors and moving. They use their unique visual perspective to feel the wonders of the night and discover those details that we have never noticed. Every time dogs look around curiously at night, every time they excitedly chase a "mysterious thing" in the dark, they are showing us the unique world in their eyes. ​

Understanding the colors that dogs see at night is not only an exploration of scientific knowledge, but also a bridge for us to establish a deeper emotional connection with dogs. When we know what colors and light and shadows the night has in their eyes, we can better understand their behavior and reactions. In the interaction at night, we can choose toys that are more suitable for the visual characteristics of dogs, such as blue or yellow luminous balls, so that they can find and chase more easily in the dark and enjoy the fun of playing. We can also pay more attention to the direction of their sight at night, follow their eyes, and discover the beauty and surprises that we have overlooked. ​

Although the colors that dogs see at night are not as rich as those of humans, they have a unique charm. Their visual system is like a wonderful gift given by nature, allowing them to shuttle freely in the dark and feel another wonderful world.