How Long Can a Cockroach Live Without a Head?

Cockroaches are among the most resilient creatures on earth. They’ve been around for over 290 million years and have outlived hundreds of species that were much higher up the food chain, including dinosaurs. And they don’t even need a head to live.

Crazy.

How long can a cockroach live without a head?

They can live for up to three weeks with no head! Here are the basics:

  • Roaches can survive without a head until they starve.
  • A roach doesn’t breathe through its head, it breathes through its legs.
  • Roaches can lay eggs even without a head.

In this article, we’ll discuss how long a cockroach can survive without its head and explain how it’s possible. 


How Long Can a Cockroach Live Without a Head?

Most species of cockroaches can live up to three full weeks without a head. Naturally, they are not able to eat, but thanks to their fascinating anatomical structure, they will still be able to breathe through their legs. Roaches can hold their breath for 40 minutes while submerged in water.

Roaches are the ultimate survivors. They can even handle massive doses of radiation (though they can’t withstand a nuclear blast).

Most species of cockroaches can live up to three full weeks without a head.

To endure starvation and prolonged dehydration, cockroaches will live off their fat storage for sustenance and slow down their breathing to prevent water loss. 

Cockroaches are cold-blooded, therefore, they rely on their environment to regulate their body temperature. A warmer body temperature requires more energy which is generated through consuming food and water.

A decapitated cockroach will opt not to regulate their internal body temperature and will use less energy. It is incredible how even without a head, a cockroach still behaves with some sort of intelligence and logic.

While cockroaches are well-equipped to survive decapitation, they will eventually die due to one of the following reasons: 

1. Dehydration

Like all living creatures, cockroaches need water to survive. Dehydration is often the most common way that decapitated cockroaches eventually die.

However, it can take days or weeks before they’re finished off. There are 3 main ways that cockroaches use and ultimately lose hydration while headless: 

  • Excretion
  • Gas exchange through breathing
  • Bodily maintenance, such as their protective coat’s outer layer

Dehydration is often the most common way that decapitated cockroaches eventually die.

Since the cockroach will not eat anything while headless, excretion will diminish. Spiracles are found throughout the cockroach’s body and are what they use to breathe. To prolong their survival, cockroaches will slow down their breathing. 

2. Starvation

As mentioned, a headless cockroach will not be able to eat, so starvation becomes the next most likely cause of death. Even if the cockroach was able to locate food without its antennae and eyes, it has no way to consume the food.

Some cockroaches can survive for over a month without food. There are 3 main physiological mechanisms that they possess that make this possible: 

3. Lipids and glycogen storage

Lipids are fats and good sources of energy, while glycogen serves as the primary form of energy. Both are stored in fat bodies, which are mainly located near the gut, intestines, and reproductive organs. 

4. Endosymbionts

These are a type of bacteria present in cockroaches that are required to create amino acids. Amino acids serve as an essential energy source, especially when lipids and glycogen levels start depleting.

Cockroaches can withstand long periods of starvation because their body continues to mobilize nutrients for up to 3 weeks. 

5. Trophocytes

These are the actual cells that store the fats. Since a headless cockroach will not be able to replenish these cells by eating, they will continue to shrink until completely depleting. 


What About Suffocation? 

Probably the main reason that cockroaches can survive without a head is that they do not rely on the head to breathe. Oxygen is absorbed through pockets found throughout the abdomen of the cockroach and is converted via tubes called spiracles.

These tubes are also located in the body rather than the head. 

Probably the main reason that cockroaches can survive without a head is that they do not rely on the head to breathe. 

In addition, cockroaches’ vascular systems work differently from other animals. Due to their small body size but large blood vessels, cockroaches don’t need high blood pressure to circulate blood (and oxygen) sufficiently. 

This also means that a headless cockroach will not bleed to death. Since their blood pressure drops, bleeding slows as well, and once the head is removed, the slow blood pressure will cause the wound to clot at the point where the head was removed.

Cockroaches also don’t require their brain or nerve cells to direct the flow or usage of blood. It’s the spiracles that are responsible for absorbing and supplying sufficient oxygen to keep the body operating, and as such, the head is not essential for this function. 

A headless cockroach will die of starvation or dehydration long before it runs out of oxygen.


Other Facts About Cockroaches

Not only can cockroaches survive for a substantial time after having their heads removed, but there are also a few other facts that you may find interesting: 

  1. Cockroaches can hold their breath for up to 40 minutes. They can even remain submerged for up to 30 minutes before starting to suffocate. 
  2. Cockroaches grow very quickly. Most species grow to adult size in as quickly as 36 days. 
  3. 1-day old cockroaches can run as fast as their parents.
  4. Despite seeming like they’re always scurrying about, cockroaches spend around 75% of the day resting
  5. They can withstand freezing temperatures, but find it hard to breed when the temps drop below 40  
  6. The world’s largest cockroach is 6 inches long and has a one-foot wingspan. 

Conclusion

Unlike most living creatures, cockroaches can survive without a head. Oxygen is absorbed through the abdomen, which allows the cockroach to breathe with no noggin.

The absence of a head does, however, mean that the cockroach will not be able to sustain its energy levels by eating and drinking sufficiently. Eventually, it will starve or perish from dehydration.