Do Dogs Have Better Night Vision Than Cats?
Do Dogs Have Better Night Vision Than Cats?
Dogs have a few anatomical adaptations that help them see in low light conditions. This is a very important ability for dogs to have, as they can hunt at night and avoid predators that are active during the dark hours.
The key is their retina, which collects light from dim environments. It then uses a mirror-like structure in the eye called the tapetum to reflect the light back to the rods and cones in the retina.
Retina
The retina is a layer of cells in the back of your eye that senses light. It contains two types of photoreceptors: rods and cones.
Rods detect motion and vision in dim light, while cones help you see color and detail. The retina is about 2% of the total surface area of the human eye.
Dogs have a rod-dominated retina, which allows them to see better in low-light conditions. This allows them to see in dark situations and avoid obstacles.
In addition to their rod-dominated retinas, dogs also have a reflective structure in the back of their eyes called the tapetum lucidum. This thin tissue reflects the light from objects and sends it to the camera-like lens of the retina.
This helps them see in dim conditions and navigate the dark, but it also scatters light. That means they don't see colors quite as well, and their ability to depict depth is limited.
Rods
The eyes of most domestic mammals, including dogs, are dominated by rod-processing photoreceptor cells. These are specialized to better see at night, helping to detect motion and shapes in dim light.
Dogs also have a special reflective membrane in their eyes, called the tapetum lucidum. This helps to reflect light twice, improving their night vision even further!
Another advantage dogs have is that they can see in a wider range of colors than humans. This can make it easier for them to spot a variety of different shades of grey and other dark colors when it’s dark outside.
Dogs have a wide visual field, so they can see farther and faster than cats. They can detect movement even from the edge of their field, which is something that helps them hunt at night.
Cones
The retina contains two types of light-sensitive cells, called rods and cones. Cones are more sensitive to light at low light levels and are associated with color vision and perception of fine detail, while rods are more responsive to brighter light levels and are associated with night vision (also known as scotopic vision).
In the human eye, cones are concentrated in the central part of the retina (fovea), where they are responsible for visual acuity, as well as color recognition. Those that are sensitive to green and red light are found mostly in the fovea, while those that are sensitive to blue light are distributed outside it.
Because rods are more sensitive to dim light, they can detect small contrasts better than cones at low light levels. This allows dogs and cats to see in the dark without having to adjust their eyesight.
Tapetum
Cats have an extra layer of tissue in their eyes, called the tapetum lucidum, that helps them see in the dark. This mirror-like membrane bounces light back onto the retina, giving more light to the rods and cones.
The tapetum lucidum makes their eyes shine, or glow, when illuminated at night. It reflects 130 times more light than a human eye does, which makes it easier for cats to see in the dark.
This extra sensitivity is important for nocturnal animals, which need to find their way in the dark. It also allows them to use the limited light available at night for their hunting purposes.
There are four types of tapetum lucida in vertebrates. These include choroidal guanine tapetum, choroidal tapetum cellulosum and choroidal tapetum fibrosum.
