Do Worms Have Eyes? How Do They Sense? Or Know Where to Go? A Guide

Ever wondered how worms get around without seeing? Or do they have eyes? And if not then how do they know where they’re going? Well, we decided to provide you with the answers!

Do Worms Have Eyes? Worms do not have eyes but some flatworms have simple eyes that can detect light. Worms have a sensory receptor in their skin that is sensitive to vibrations, touch, lights, and chemicals. It’s through receptors that worms can sense what is around them and move accordingly without the need to see.  

As much as all these facts might sound unusual to us, there’s more to discover about worms and their visionary differences. So, let’s dive right in.

Earthworms have been around for about 120 million years and have primitive sensory systems, with no eyes. Primitive creatures with no eyes, limbs or ears to provide them with sensory information about their surroundings. Which might make it difficult for us to comprehend because of course, we use these senses a lot.

What do worms have instead of eyes?

As mentioned, most worms have a sensory receptor in their skin instead of eyes. Whereas some predator worms have sensitive tentacles on their heads, which helps them sense and capture their food without having to see it. So one might say they do sort of have ‘arms’ after all!

The receptor cells in the worm’s skin are very important when it comes to making up for not having eyes, especially those that are positioned at the front end. This is because these receptors are the ones that help worms register the presence of light, even though they have no eyes.

Now the next common question that may come up is why bother to sense light if they don’t have eyes.

Why worms need to sense light if they have no eyes

Worms can become paralyzed if they’re exposed to light for more than an hour or so. So worms must be able to sense light, even if they can’t see it directly. This is why worms are capable of sensing different intensities of light using their receptors.

earth worm eye sight

Worms are capable of sensing different colors of lights. Worms move away from white and blue lights and they show no reactions to red lights. So, if you’re on the search for worms at night you can easily spot them better without them getting away if you use a light with a red filter across the lens.

It’s also through this light-sensing ability that worms are able to know in which direction they should move.

And with that being said, to finish up, let’s address the next most obvious question people have…

How do worms know where to go? 

What helps worms know where to go is their sensory perceptions. As mentioned, worms have receptors in their skin. These receptors transmit information to a very primitive and simple brain. 

This information transmission by the receptor then directs the movements of the worms. This is how the worms know where they need to go.

The light-sensing abilities are also possible because of the sensory information provided to the brain. The ability to detect light and the combined information transmission is what helps worms from drying out in sunlight (by transmitting the information as to when to come out of the soil as a response to the light intensities sensed or felt) 

Also, the receptors help in sensing vibrations of animals and weather conditions on the soil surface, which effectively helps worms not to move in that direction or avoid worms from coming up to the soil surface. Or adversely, it enables them to come to the surface when it’s raining to avoid being trapped in waterlogged areas. 

All in all the direction worms should move depends on the receptor response and the corresponding information transmitted to the brain.

To end…

We hope this has been useful in answering some of those strange questions you may have about worms! It’s a fascinating world and even if you want to explore it even more up close, here are some resources which might help you.


A Certified Ecologist and an Entomologist, Michael has been interested in all aspects of Nature for many years. It's only now he's decided, along with his partner Fran, to begin documenting what he knows.

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