Do Cockroaches Have Brains?

Are-cockroaches-smartCockroaches are generally seen as dumb insects that only want food and water to live. They are not even smart enough to avoid the traps. Their abrupt behavior may have made you wonder: “Do cockroaches have brains?” Yes, they have, but there is only one primary brain.

The main brain of cockroaches performs technical functions. However, they have a bundle of nerves, known as ganglia, that spreads throughout the body. It controls movement, breathing, and nervous responses. The central brain is in the head, and the ganglia are found throughout the insect’s body.

You’ll be surprised that cockroaches can even learn how to adapt their behavior according to the environment. These tiny bugs can even live up to a week without their heads. So are cockroaches intelligent? Let’s dig deeper!

Do Cockroaches Have Two Brains?

Cockroaches don’t have two brains. We all have heard from our childhood that cockroaches have two brains. The central part of the organ is situated in the head, while the other lies in their butts. As bizarre as this sounds, it’s practically right but technically wrong.

Let’s make it simpler. Like most living creatures, cockroaches also have one central brain in the head. They also have nerve clusters or bundles in the rest of their body responsible for carrying out secondary but necessary functions.

Technically speaking, nerve clusters can’t be an actual brain. So, from the scientific point of view, roaches don’t have two brains. But practically, this nerve bundle acts as the second brain. Thus, cockroaches do have two brains spread throughout their body.

The brains of cockroaches are very advanced. So they can continue living even when you eliminate their head and cut off the traditional brain from the body. That is because their second brain sends signals and commands to the body to survive for days. So starvation is the only way they can die without the head.

What Is the Structure of the Cockroach’s Main Brain?

The brain structure of cockroaches differs from humans and mammals. Roaches’ brains don’t consist of traditional lobes. Instead, they are in a mushroom-like shape and are sensitive to sensations and vibrations. Their mushroom brain is broken down into multiple pieces, known as mushroom bodies.

These small bodies coordinate to help the roach move around its surroundings and sensory stimulation with accuracy. When researching the functionality of the cockroach brain, researchers reported that even a tiny vehicle rattling outside the study vicinity could cause disruption.

The tiny head of cockroaches can only contain a small brain. But yet, it has more than 1,000,000 cells compared to humans, who have approximately 100,000,000,000 brain cells. That is a good number of cells, considering the roach’s small body size.

Like mammals, roaches also have neurons. They use them to process information that their antennae gather, which are located on the bug’s head and sense smell, sound, and vibrations.

Ganglia: The Second Brain of Roaches

Now let’s discuss the second brain of the roaches. It doesn’t look like a mushroom, nor does it possess brain cells or neurons. Instead, it is a complex cluster consisting of many nerves called ganglia.

The ganglia are spread throughout the roach’s body. On the other hand, the nerve tissue is focused on the back of its body. A cockroach uses the ganglia to move their limbs.

If you successfully eliminate a roach’s head, you still see them moving and running everywhere. As scary as the bug looks, it’s due to these ganglia that they can still use their basic instincts, i.e., searching for food and shelter.

The second brain or ganglia of roaches helps them in:

  • Responding to sensations
  • Interpreting stimuli
  • Excretion
  • Breathing
  • Climbing
  • Flying

Ganglia help roaches survive for up to a week without the head. But they can’t repair their body nor communicate with other cockroaches without the central brain. Plus, they wouldn’t be able to find food and will most likely starve to death.

You’ll be amazed to know that ganglia can translate the information and send commands to the body to respond in cases of danger. This is why you see a headless cockroach bumping insecticides and traps like an expert. It’s all because of their second brain.

Where Are Both Brains of Cockroaches Located?

Like every living thing, the primary brain of cockroaches is present in the head. However, the second brain is spread throughout the insect’s body.

According to the Journal of Visualized Experiments, a cockroach’s neural circuit is a decentralized control process. The ganglia consist of multiple nerves connected to each other, primarily in the abdomen and thorax. Each nerve cluster can perform its functions without the brain’s input.

This decentralized second brain, or ganglia, is connected with a ventral nerve cord (VNC). Every cluster performs different functions.

If you’re thinking of ganglia as nerves, you may be wrong. These nerve bundles are too complex to be a nerve. Yes, humans also rely on their nerves to transmit signals, but they can’t understand them without their main brain.

That’s what makes roaches unique. They allow their second brain or nerve bundles to function without relying on the main brain. This is why it makes more sense to call these nerve bundles their second brain instead of just nerves.

The Experts Say: a Cockroach’s Brain Functions Like Honeybees

You may think roaches should be very smart because of their two brains, but why do they act dumb? Experts say these roaches are super intelligent. However, their thinking mechanism and cognition don’t work like humans. Instead, it is closer to honeybees!

Brandon Keim from Aeon Magazine took a closer look at these insects. He found that roaches work in groups. When living in colonies, they make a mutual decision about where to find shelter and food. These bugs communicate through chemical signals rather than any particular dancing pattern.

When living in isolation, individual cockroaches may show unusual behaviors. For example, they use their spatial memories to navigate and recognize their family members.

The research was conducted by Dr. Mathieu Lihoreau and his team at Queen Mary’s School of Biological and Chemical Sciences on cockroaches’ cognition and behavior. They found that cockroaches possess associative learning, communication, and memory functions similar to honeybees.

What Does a Roach’s Both Brains Do?

A roach’s primary brain performs a large part of its regeneration capabilities and pheromone production. The head keeps the hormones stored to grow and molt and also determines the exact time to release scents and interact with other cockroaches. Their second brain performs breathing and control movements.

Generally, a roach’s both brains perform these functions:

  • Manage regeneration abilities
  • Dictate pheromone production
  • Communicate with other cockroaches
  • Find the ideal food places and shelter to live and reproduce
  • Process hormones required to grow and molt
  • Carry out crucial functions, such as nervous, digestive, and respiratory systems
  • Control movements

What is the Size of a Cockroach’s Brains?

The size of the roaches’ main brain is even smaller than a peanut. Since these bugs are relatively small, their brains are almost the size of a pin. It can even be smaller based on the cockroach species.

When it comes to their second brain or ganglia, they are also not large, considering the size of the insect. Instead, these nerve clusters are wide, spread throughout the segments of the roach’s body.

What Is a Cockroach’s Average IQ?

The average IQ of cockroaches is still unknown, but we all know they are not mindless. These tiny bugs have an excellent intelligence that helps them dodge your instant stomping and insecticide sprays.

They obviously can’t match humans’ consciousness or thought processing level. A roach’s brain is primitive like every other insect. Yet, they are among the smartest and most intelligent insects.

How Do Roaches Use Their Brains?

Cockroaches may not be on the same level compared to other intelligent animals. For instance, these insects are less clever than dolphins, chimpanzees, and parrots. But, like these animals, roaches can’t perform tricks or solve puzzles.

Throughout the cockroaches’ life history, researchers have concluded that these bugs can:

  • Learn different behavioral patterns
  • Judge the situations and react accordingly
  • Maintain memory and use it to respond to stimuli

Here are 3 mind-blowing intelligent things that roaches are capable of:

Using Memory to Remember Scents

Cockroaches function with scents. They use chemical odors to communicate with other roaches and leave trail marks for other bugs to follow. Cockroaches memorize these scents and detect them to know:

  • The location of other roaches
  • Food or shelter sources
  • If an insect died in any place
  • The place of predators

The mushroom bodies of roaches manage memory and olfactory learning. These bodies detect the sensory input, process it, and let the bug make decisions based on the available information. As a result, cockroaches can easily detect danger, follow the scent trails, and avoid going near hazards.

Making Correct Judgments

Cockroaches can make judgments based on their experiences. A study at Vanderbilt University found that roaches naturally stay away from the peppermint scent. The researchers tried to make cockroaches ignore their instincts and go near the peppermint. They associated the smell of peppermint with food.

Cockroaches were taught to move towards peppermint instead of vanilla, which roaches love. Then, the researchers left these bugs out in the open. The results showed that cockroaches are smart enough to second-guess the information they are given.

These bugs don’t just blindly follow the scent command. Instead, they make correct judgments depending on their bad and good experiences.

Utilizing Memory in Learning

Cockroaches are smart learners, but do they have memory storage? Yes, the roaches’ mushroom bodies store necessary information and process them. Whatever cockroaches learn from their experiences is also saved in their memory storage.

Cockroaches learn very quickly. A few experiments show cockroaches learn faster when responding to certain stimuli and conditioning. In addition, their short-term memory can influence the insect’s behavior.

However, no evidence confirms the duration roaches can remember their lessons.

How Better Can Cockroaches Learn?

Roaches can learn and adapt to a specific limit. For example, a study published in Behavioral Ecology observed the cockroach’s response to a temperature-sensitive parasite. The researchers found that two species of roaches, Supella longipalpa and Blatta orientalis, moved toward colder environments.

The parasite was cold-intolerant, and roaches sensed that already. This shows that these bugs can detect new information, adjust their response, and make decisions accordingly.

The learning behavior of roaches varies the entire day. They learn better at night or evening and bad in the morning. They also remember the lessons they learn in the evening as memories for a long time. On the other hand, the evening lessons usually fade.


Does a Cockroach Have Memory?

A cockroach has memory storage where they save necessary information, process it, and translate it to convey it to the entire body. In addition, the bug can also store its experiences in memory storage, which helps them respond according to different situations.

Do Cockroaches Have Two Brains?

Cockroaches practically have two brains. One is located in the central head, which performs regenerative abilities and produces pheromones to communicate through chemical signals. The other brain, also called ganglia, is a nerve bundle spread throughout the body, performing different functions like breathing, excretion, and digestion.

Do Roaches Have Feelings?

Roaches don’t have emotional feelings or attachments to their owner or family members. But they can feel curiosity, hunger, and fear. So you can’t hurt roaches’ feelings, but you can scare them away.


The cockroach brain has evolved a lot throughout its lifetime. Their brains know all the recent advancements to communicate and make knowledge-based decisions.

These bugs practically have two brains; one is the main brain located in their head, while the other is a nerve bundle called ganglia, which is spread throughout their body.

So do cockroaches have brains? Here is what you need to know:

  • The main brain of roaches performs regenerative abilities, produces pheromones, and helps in growth.
  • Ganglia performs necessary functions, such as breathing, excretion, flying, climbing, and responding to stimuli.
  • Ganglia can perform its functions even without the central brain. This is why roaches can live up to a week without the head.
  • Roaches are quick learners and use their memory to judge situations and make decisions.