Do Worms Have Brains? All You Need to Know!

Do Worms Have Brains? All You Need to Know!

Worms aren’t exactly top of mind when you think of science. They’re more associated with filth, dirt and the smell of rotting food than anything scientific.

But worms are much more than that! And their biology is fascinating in its own right. In this article, we’ll explore everything you need to know about worms, from the different types to their importance in the ecosystem and how they think.

Do Worms Have Brains?

A little about worms:

With over 10,000 species in the world, worms are found in all parts of the planet, living underwater, on land, in the air, and even inside other organisms. While not as famous as insects and spiders, worms are actually very important in the ecosystem.

When scientists look at the brain of a worm, they’re really looking at the nervous system of the worm. The brain is just another part of the nervous system, and understanding it can give scientists an important clue about the rest of the body.

Their brains yes brains in multiple sit next to their nervous systems and organs. Although they have brains they aren’t as complex as ours.

Nerouns In a Worms Brain

With simply 302 neurons and 7000 connections, it has a much simpler nervous and brain system than our complex 100 billion neurons. 

Yes, that’s a huge difference but that’s why humans are the smartest living things on the planet.

How Many Brains Does a Worm Have and Why?

Technically speaking worms have two brains.

Worms have very small brains compared to the rest of their bodies. Earthworms for say have two ‘cerebral ganglia’ that connect to different parts of their bodies.

Worms are invertebrates, and they are very simple beings. Because they lack a complicated body plan and organs, they don’t need a complicated brain. Insect brains are very complex, and vertebrate brains are even more complex.

Why Do Worms Need To Have a Brain At All?

Kind of a silly question, but we said we’ll add it for any of those wondering or looking for a proper answer.

Worms have brains to make decisions about the worm’s body, like deciding when to move. If the worm lacks a sense of self, then it might not know when to move.

Worms have an extremely complex nervous system with a great many types of neurons. But it’s the way the neurons are organized that makes the nervous system so complex.

Are worms intelligent?

Many scientists think so! Worm nervous systems are relatively simple, with fewer types of neurons (302 to be exact) than vertebrate nervous systems, but worms can process information very quickly. There was a study that found that worms have free will meaning they are like any other animals and even us humans.

You can read about free will –

Some worms are also very social, with different worms cooperating to solve problems like how to get food. Many worms are also hermaphrodites, meaning they can change their sexes. This makes them especially interesting to scientists as they can watch how hermaphrodites change sex and how this affects their nervous systems.

Worms can also sense certain chemicals in the air and on surfaces. For example, one species can detect the chemicals released by the skin of a person who has just eaten food. This could allow the worm to know when it’s time to eat food, as well as indicating that the worm is quite intelligent!

Yes, fascinating isn’t it

Is a Worms Brain Complex?

The human brain is often said to have 100 billion neurons, which have connections between them called synapses. Worms also have a complicated nervous system. But unlike vertebrates, they don’t have a centralized brain, where all the nerves come together.

Instead, they have a nerve ring around the worm’s esophagus, where the food enters the worm. With this nerve ring, nerves can leave the worm’s body and enter another worm to exchange information. This is how worms exchange information and make decisions.

Yes, a worm’s brain is complex. Though not as complex as other animals. They are still extremely complex.

Brain size can also be used as an indication of intelligence. Some animals, like sea sponges, have very small brains. It’s thought that they don’t need a complicated brain because they live in the ocean and don’t have many predators.

But others, like the squid and octopus mentioned above, have very complicated brains. They live in an environment where good decision-making is important, so it seems likely that the brain has a role in their complex behavior.

Like the human brain, it’s thanks to the worm’s brain that worms:

  • Breathe
  • Regulat body temperature
  • Detect light using their light receptors
  • Hearts pump
  • Detect animals moving nearby
  • Able to use their circular and longitudinal muscles, as the body moves forward.

These might seem like simple tasks but they are extremely complex.

Fun Fact: Worms also feel pain. This is due to their brain detecting it.


Worms are important organisms in the ecosystem, playing important roles in the breakdown of food, soil nutrient recycling and decomposition. They’re also very complex organisms with a very complicated nervous system.

While worms are not as well-known as insects and spiders, they are actually one of the most abundant organisms on the planet. And their biology is fascinating in its own right. Worms have a very small brain compared to the rest of the body, which is why scientists think they don’t need a complicated brain.

DrWorm - Vermicomposting enthusiast and avid worm researcher for the last 25 years. Interested in what earthworms eat and how to farm and breed them. His garden wouldn't be the same without the help of mother nature's finest fertilizers!