Do dogs have green eyes at night?

Answered by Douglas Hiatt

Dogs do not actually have green eyes at night. However, the tapetum lucidum, a specialized layer of tissue located behind the retina, is responsible for the green glow you may see in their eyes when light is shone upon them in the dark.

The tapetum lucidum acts like a mirror, reflecting light back through the retina. This reflection helps to enhance a dog’s night vision by giving the photoreceptor cells in their eyes a second chance to capture any available light. It effectively increases the sensitivity of their vision in low light conditions.

The green color that we perceive is due to the structure and composition of the tapetum lucidum. It contains specialized cells called guanine crystals that reflect light in the green wavelength range. This is why the eyes of many animals, including dogs, often appear green when illuminated in the dark.

It’s important to note that not all dogs have this green glow. The intensity and color of the reflection can vary depending on the breed and individual dog. Some dogs may have a more intense and noticeable green glow, while others may have a less pronounced effect.

It’s also worth mentioning that the tapetum lucidum is not exclusive to dogs. Many other animals, such as cats, deer, and horses, also possess this structure in their eyes. The purpose remains the same across species – to enhance their night vision.

So, while dogs don’t actually have green eyes at night, the tapetum lucidum is responsible for the green glow that we often associate with their eyes in low light conditions. It’s a fascinating adaptation that helps them see better in the dark and navigate their surroundings more effectively.