How snakes see is often misunderstood. For instance it is a misconception that snakes are almost blind. While their vision isn’t as acute as a persons they have other tools that work in harmony with sight to give them a very robust image of the world around them. Their hearing, despite a lack of external ears, is superb. They have an excellent sense of smell, so acute that it allows them to track the exact direction their prey is going turn by turn. In addition there some snakes, the most infamous of which are the pit vipers, that have a special infrared vision.
Here are some interesting tidbits of information about a snakes vision.
- Snakes have cones in their retinas; cones is what allows us to perceive color. It is the same for them, but not as vivid nor wide a range. Think in terms of hues and shades
- They have trouble seeing things that aren’t moving. That’s where other senses such as smell (flicking of the tongue), and heat signature (in the snakes equipped by nature for it) come into play
- A snake is very near sighted
It is NOT true that you can tell a venomous snake by the shape of its pupils
- Many animals were created with a special oil drop that surrounds the cones of the eyes to protect them from ultraviolet light. Snakes instead rely on a filter over the lens of their eyes that can not be penetrated by the uv wave length
- A snake has eyes with a telescoping lens. They can move the lens itself forward and backward (in and out) with muscle contraction/relaxation
- A snake has no eye lids. They have a clear scale over each eye that comes off when they shed their skin
- In general snakes can see better at night because their rods are more highly developed than the cones. Which is the opposite of you and I. The cones in our eyes are better developed and that allows us to see colors in much more vivid tones
- One sign a snake is going to shed is its eyes become opaque about 5 to 7 days before it happens
- Sometimes a shedding snake will not shed the scale on its eyes. This is often a sign that the humidity is too low