It is a common belief that snakes are able to see in the dark. However this is not true. Snakes do not have night vision but they can see in the dark using a method called “light scattering.”
When light hits the eye it is scattered in all directions. The back of the eye is covered in a layer of cells called the retina. These cells are sensitive to light and send signals to the brain when they are hit by light.
The retina is made up of two types of cells: rods and cones. Rods are sensitive to low levels of light but they cannot see color. Cones are sensitive to high levels of light and can see color.
Most snakes have more rods than cones in their eyes. This allows them to see in low levels of light but they cannot see color.
Some snakes such as the boa constrictor have more cones in their eyes. This allows them to see in high levels of light and see color.
Snakes use light scattering to see in the dark. This means that they are not able to see as well in the dark as they can in the light.
There are some snakes that can see in the dark better than others. These snakes have a special type of eye called “pit organs.”
Pit organs are found in the head of the snake and are sensitive to heat. This allows the snake to “see” the infrared radiation given off by warm-blooded animals.
Pit organs are most common in snakes that hunt at night such as the viper.
Not all snakes have pit organs. Some snakes such as the king cobra do not need them because they hunt during the day.
So do snakes have night vision? No but they can see in the dark using light scattering and pit organs.