Modified & Updated: 30 Dec 2023

Cockroach, Cockroach Facts

Many shudder at the thought of cockroaches. It’s understandable why. They can infest homes, carry various diseases, and some may even leave a foul odor in their wake. They’re widely regarded as unsanitary pests, but most cockroach species are actually quite harmless and will not invade your home. These misunderstood insects have existed for millions of years, and many even suggest that they are capable of surviving even nuclear war. Is this a scientific fact or just another popular myth? Find out and learn more about these fascinating creatures with these creepy cockroach facts.

  1. Like all insects, cockroaches have six legs.
  2. The order of cockroaches comprise around 4,600 species in over 460 genera.
  3. North America is home to around 50 species of cockroaches.
  4. Australia is home to approximately 450 species of cockroaches.
  5. Their bodies are made up of three segments: the head, the thorax, and the abdomen. Cockroach abdomens have ten segments.
  1. The word “cockroach” stems from the Spanish word cucaracha.
  2. Katsaridaphobia is the fear of cockroaches.
  3. They are mainly nocturnal animals.
  4. Cockroaches typically have flat, oval-shaped bodies.
  5. Cockroaches live in almost every continent except Antarctica.
  6. They can even survive in Arctic regions, but they prefer the warmer climates of the tropics and subtropics. Some species can even hibernate.
  7. All cockroaches belong to the taxonomic order Blattodea.
  8. Cockroaches find each other through chemical signals called pheromones.
  9. They breathe through holes at the sides of their bodies. Scientists refer to these holes as spiracles.
  10. Some people refer to the American cockroach and the Florida woods cockroach as “palmetto bugs”.
  1. Some female cockroaches can store the sperm of male cockroaches; they can mate only once and produce baby cockroaches for their whole lives.
  2. Cockroaches can survive for months without eating and one week without drinking water.
  3. Their nervous systems can have up to one million nerve cells, and they are capable of learning.
  4. The Greeks have used cockroaches for medicinal purposes in Classical times.
  5. Cockroaches can survive without air for up to 45 minutes.
Table of Contents

Cockroaches can live for up to a week without their heads.

Because cockroaches do not breathe out of noses and instead use openings in their bodies to breathe, they can survive for a surprisingly long time without their heads. They can also achieve this feat because they don’t need their brains to do basic functions such as breathing and moving around. Their nervous system can still operate normally, allowing them to stand, react to touch, and run around like normal.

However, the caveat is that they can neither eat food nor drink water without their heads, so they will likely die of dehydration within a week or less. Nevertheless, it’s still one of the most impressive cockroach facts!

They can survive radiation levels that could be lethal to humans.

Popular media suggests that cockroaches will likely rule the Earth when humans exterminate themselves due to nuclear warfare. This notion holds some truth to it because cockroaches can withstand radiation levels up to 15 times the lethal dose for humans. However, they’re not indestructible.

Their resistance to radiation could be due to the fact that cells are much more vulnerable to radiation when they’re dividing, and cockroach cells don’t divide much unless they’re undergoing the process of molting. Although this could allow cockroaches to survive a quick burst of radiation, prolonged exposure to radiation (which would be a likely result of nuclear warfare) could potentially damage the cells of molting cockroaches. Now that’s among the cockroach facts that you wouldn’t want to forget.

Termites evolved from cockroaches.

Although they look more similar to ants than any living cockroaches, termites are not closely related to ants — they’re actually a branch of eusocial cockroaches. The relationship between termites and cockroaches has been the subject of much scientific debate, but recent studies have shown that termites have evolved from cockroaches.

Termites belong to the order Blattodea just like any other cockroach. Scientists deem these invasive insects as a sister group of the genus Cryptocercus or wood-eating cockroaches. Genetic studies reveal that termites branched off from other cockroaches roughly 150 million years ago and developed into highly social insects before ants and bees evolved.

Cockroaches are highly social insects.

For most cockroaches, there is strength in numbers. They often live together in groups, and some species of cockroaches can even have complex social structures. Cockroaches communicate with each other mostly through smell and touch, and they can recognize their kin as well as exchange information regarding resources such as food and shelter. A few species may even display a division of labor.

As social animals, cockroaches can also develop behavioral problems and oddities if they grow up in an isolated environment. In some studies, researchers noted that isolated cockroaches spent less time eating, were less likely to explore their surroundings, did not interact much with other cockroaches, and took longer to identify a mate.

They can make group decisions.

Cockroach Colony, Social Cockroaches
Source: Pixabay

Aside from being social insects, cockroaches can also make group decisions. American cockroaches can have unique individual personalities when it comes to boldness and shelter-seeking behaviors. In addition to this, they also display group personalities wherein different colonies act uniquely as a group. They conform with members of their colony and make decisions to which the whole colony will follow. Groups of cockroaches can decide on where they should hide judging by how dark the area is and how many cockroaches there are in the area. Also, there seems to be a balance between competition and cooperation within the groups.

Cockroaches wash themselves after touching humans.

We typically view cockroaches as unsanitary and disgusting, and it turns out that the feeling seems to be mutual. When cockroaches come in physical contact with humans, they run away as quickly as possible. Afterwards, they attempt to clean themselves. While this might appear to be a display of disgust, some experts suggest that cockroaches might just be acting out impulses of self-preservation.

Cockroaches lived alongside dinosaurs.

One of the most interesting cockroach facts is that their ancestors have been on Earth even before the first dinosaurs existed. Fossils of cockroach ancestors date back to the Carboniferous period, around 300-350 million years ago. However, cockroach ancestors had external egg-laying apparatuses or ovipositors instead of internal ovipositors like in modern roaches. Furthermore, those ancestors also are the ancestors of mantises. Fossil records suggest that modern cockroaches with internal ovipositors evolved during the Cretaceous period around 145 to 66 million years ago. This means that modern cockroaches lived at the same time as the famous dinosaurs such as the T. rex and the velociraptor.

They are highly adaptive animals.

Cockroaches can live almost anywhere in the world because they are generalists who can adapt to a wide variety of environmental conditions. Furthermore, unlike many other insects, they did not evolve to have a specialized diet and are generally omnivorous.

Because of their non-specialized diet, they can feed on a diverse set of food items. Some species, such as the American cockroach (Periplaneta americana) can feed on a wide variety of unusual food items such as leather, glue, paper, hair, skin flakes, soiled clothes, and even the starch in book bindings. Such a diverse diet helps them thrive in many parts of the world.

Cockroaches can digest numerous food items because they harbor various bacteria in their digestive tracts that help them break down the material they consume. However, some species may produce enzymes in their saliva that help them digest cellulose, a complex sugar that exists in the cell walls of plants and also in plant-based materials such as paper, wood, and cotton. This is especially important in wood-eating cockroaches, whose diet mostly consists of wood, as the name suggests.

They often run away when exposed to light.

If your home has cockroaches, you likely have noticed that cockroaches run away as soon as you switch on the light. The Roman poet Virgil even named cockroaches “Lucifuga”, which means “one that avoids light”. This is not because cockroaches fear the light itself; they fear you seeing them. They often hide under the cover of darkness because their survival instinct is to avoid detection from predators. However, the Asian cockroach (Blattella asahinai) is notably attracted to light and bright surfaces.

The biggest cockroach species can grow up to over three inches long.

Cockroaches vary greatly in size. Most species of cockroaches are quite small, only reaching the size of a thumbnail. However, some species can grow pretty large, especially those who are native to tropical or subtropical regions. One of the most mind-blowing cockroach facts is that the biggest living cockroach species, Megaloblatta longipennis, can grow up to 3.8 in (9.7 cm) long. This cockroach, which is native to Ecuador, Peru, and Panama, also has wings that span up to 8 in (20 cm). It’s a good thing these roaches aren’t the ones you can find at home!

Some species can emit sounds.

Aside from communicating through touch and chemical signals, some cockroaches can also communicate through sounds. A few of them can make chirping or buzzing sounds, while others can produce sounds by rubbing parts of their body together.

One of the most famous examples of sound-producing cockroaches is the Madagascar hissing cockroach (Gromphadorhina portentosa), which can produce its characteristic hissing sound by forcefully ejecting air from their spiracles or breathing holes. They can produce different kinds of hisses that communicate various signals such as courtship, aggression, or disturbance. Some cockroach species, particularly in Australia, vibrate and produce sounds as part of their mating ritual. They may also drum on the ground if a potential mate is present.

Not all cockroaches can fly.

German Cockroach, Flying Cockroach
Source: Pixabay

Cockroaches vary a lot from species to species — some have wings, while others don’t. Wingless species such as the Madagascar hissing cockroach are unable to fly. Some species, such as the German cockroach (Blattella germanica), have wings but can barely fly. Others, such as the American cockroach, can fly using their fully-functional wings.

In some species, such as the Dubia cockroach (Blaptica dubia), only the males have wings while the females only have non-functional wing stubs. In winged species, the roaches typically have leathery outer wings that protect the sensitive and membranous inner wings.

They can carry diseases.

Many people have an innate fear or disgust for cockroaches, which is completely understandable. That’s because household cockroaches often carry disease-causing bacteria and viruses. These pest roaches often live in sewers, drains, dumpsters, and other unsanitary areas. Because of this, they potentially spread ailments such as diarrhea, cholera, typhoid fever, or even leprosy. Truly some creepy cockroach facts to remember!

They can trigger asthma attacks and cause allergic reactions.

In addition to potentially carrying disease-causing microorganisms, cockroaches can also cause asthma attacks and allergic reactions in some people. Interestingly, if you’re allergic to shellfish and dust mites, the odds are that you’ll also have an allergic reaction to cockroaches. This is because shellfish, dust mites, and cockroaches all possess a similar protein called tropomyosin. These proteins serve as allergens that trigger allergic reactions, and they exist in the bodies, saliva, shed exoskeletons, and feces of cockroaches.

Cockroaches like beer.

Not only do cockroaches have an alcoholic beverage named after them, but they also apparently are attracted to alcoholic beverages. They particularly have a fondness for beer — but they don’t drink it to get drunk like the rest of us. Cockroaches just like the hops and sugars that the beer contains. Now you have some creepy cockroach facts to share while sharing a couple of bottles with your friends!

Some of them can emit foul odors.

Aside from potentially contaminating homes and food, a few species of cockroaches also leave offensive odors. These strong, musty odors often can linger in the air and alter the taste and smell of food, making them unappealing. They can also leave a foul smell as they die and decompose.

Cockroaches are among the fastest running insects.

If you’ve ever chased after a cockroach in your home, then you’ll likely be already aware of this fact. Cockroaches move fast, and they’re among the fastest running insects alive today. The American cockroach, for example, can run at speeds of up to 3.4 mph (5.4 km/h). While the speed alone may not sound impressive, they’re actually moving at 50 body lengths per second. If these cockroaches were humans, they would be running up to 210 mph (330 km/h). Certainly one of the most impressive cockroach facts!

Cockroaches can squeeze through extremely small gaps.

You can leave your doors and windows closed all you want, but some cockroaches can still get inside your home. This is because cockroaches have extremely flexible exoskeletons that allow them to squeeze into even the tiniest of crevices. They can also splay their legs to the side, allowing them to essentially flatten themselves and still walk towards the exit. Impressively, cockroaches can still run almost at full speeds even while in their flattened positions.

They can withstand weights up to 900 times their own body weight.

Not only are cockroaches fast and agile, but they’re also surprisingly strong. Because of their flexible exoskeletons, cockroaches can also handle being squashed by weights of up to 900 times their body weight. Because of this, they can survive relatively minor smacks with no problem. Cockroaches can also carry things as heavy as 50 times their weight using their mouthparts.

Some species of cockroaches are popular as exotic pets.

Madagascar Hissing Cockroach, Hissing Cockroach, Pet Cockroach
Source: Pixabay

Although most people tend to find cockroaches repulsive, some exotic pet owners keep cockroaches as valuable pets. A popular pet cockroach is the Madagascar hissing cockroach, which is a large and docile type of cockroach. These insects also tend to have individual personalities and have the added appeal of making hissing noises. They are hardy and generally harmless pets and only require a small living space. When keeping these cockroaches as pets, however, it’s ideal to provide them with a hiding space because they tend to avoid the light.

Some pet owners also keep cockroaches as feeder insects. They feed cockroaches to insectivorous pets such as reptiles, fish, birds, or predatory arthropods. Cockroaches are excellent sources of protein and fat for these animals.

They reproduce rapidly.

Another reason why cockroaches thrive in a wide range of areas is that they tend to reproduce rapidly. They take quite long to mature, typically a few months to a year. However, when they mature, they can produce up to 300 to 400 young cockroaches or even more in their entire lifetime (typically only a year, but can reach up to four years). Some species can even reproduce asexually and produce offspring on their own without the help of males.

Some cockroaches give birth to live young.

Most cockroaches lay egg cases that contain around 40 to 50 individual eggs. They drop these egg cases just before the eggs hatch. However, some cockroaches (such as the Madagascar hissing cockroach), give birth to live young. They are ovoviviparous, which means that they carry their eggs inside of their bodies, and these eggs also hatch within the bodies. They then give birth to already-hatched young cockroaches, which are white but will darken over time.

At least one species of cockroach can produce milk.

One of the weirdest cockroach facts is that one species (Diploptera punctata) can produce milk to feed their young. This milk isn’t the typical milk we’re used to — they’re more of nutrient-rich crystals rather than the liquid milk we know.

Scientists also deem this “cockroach milk” as a superfood because it contains high concentrations of protein, fat, and carbohydrates. It also provides all nine essential amino acids that are crucial for protein synthesis. However, harvesting this milk is not easy and can raise ethical concerns because it involves killing female cockroaches after they’ve given birth.

Only a small percentage of cockroaches are pests.

While most people view cockroaches as nasty home-invading pests, these pest species make up only a small minority of cockroach species. Out of around 4,600 species of cockroaches, only around 30 species dwell in human homes and act as pests. Among these are the American cockroach (Periplaneta americana), Australian cockroach (Periplaneta australasiae), German cockroach (Blattella germanica), and Oriental cockroach (Blatta orientalis). The vast majority of cockroaches are harmless and don’t associate with human habitats.

It’s notoriously difficult to exterminate them.

Due to the potential health risks that cockroaches carry and their generally unwanted presence, there have been many attempts to control their populations. Traps that contain known pesticides such as fipronil and boric acid powder seem to show success at exterminating adult cockroaches, and there are some baits that contain egg killers to further control their population growth. However, recent studies have shown that cockroaches are slowly developing immunity to some pesticides and can pass this resistance to their offspring.

Many animals serve as their natural predators.

While cockroaches may indeed seem indestructible especially because of their increasing resistance to pesticides, they have a large number of predators in the wild. Their natural predators include spiders, centipedes, scorpions, as well as some species of insects, reptiles, mammals, and birds.

Some species of wasps actually specialize in feeding on cockroaches or their eggs. Most notably, the emerald cockroach wasp (Ampulex compressa) heavily relies on cockroaches as a part of their unique life cycle. Female emerald cockroach wasps sting cockroaches to temporarily paralyze them, and they sting at just the right spot in the cockroach’s brain to suppress their escape reflex.

Afterwards, they take control of the cockroach by pulling on the cockroach’s antennae similar to pulling a leash. They lead the roaches to a burrow wherein they then inject their eggs into the bodies of the cockroach. When the eggs hatch, they feed on the insides of the cockroach until the cockroach dies. Interesting yet terrifying, don’t you think?

They are valuable animal models for scientific research.

Cockroach Pest
Source: Pixabay

Because cockroaches are hardy, easy to breed, and require relatively few resources, they are valuable animal models for scientific research. Cockroaches are particularly useful in the fields of animal social behavior, reproductive physiology, and neurobiology. They are also popular choices in various experiments regarding spatial intelligence, learning, and aggression, among many other experimental topics.

Some researchers have also created “cockroach robots” which are small, flexible, fast, and hardy, similar to real cockroaches. These cockroach robots have promising implications for search and rescue operations because they can easily fit through small gaps in debris and can withstand extreme weights. That’s certainly one of the coolest cockroach facts out there.

Cockroaches have reproduced in outer space.

Yes, scientists have also sent cockroaches to space — more importantly, cockroaches have successfully reproduced in the microgravity conditions of outer space. Russian scientists launched the Foton-M 3 bio-satellite into space, and they placed some unlikely inhabitants within the satellites — insects, including cockroaches. One of them was Nadezhda, a female cockroach who conceived offspring with another cockroach during their spaceflight. She later produced 33 offspring back here on Earth. The scientists noted that these cockroaches were overall similar to normal cockroaches, but the coloration of their carapace darkened much earlier than usual.

Cockroach farming exists in some parts of the world.

Although it does sound gross and otherworldly, cockroach farming definitely exists. It’s a type of insect farming that focuses on keeping and breeding cockroaches as livestock. The cockroaches are used for human consumption, traditional medicine, or as feeders for pets. These farms are especially popular in parts of China, where they keep millions of cockroaches in large buildings. As of 2013, around 100 cockroach farms were operational in China!

Cockroach farms are profitable due to the relatively low cost of keeping and breeding cockroaches. They’re hardy and aren’t susceptible to dying off of diseases themselves. Moreover, they can avoid food that is toxic to them.

However, these cockroach farms still come with their fair share of problems. Most notably, the escape of captive cockroaches can lead to disastrous damages in the establishment’s surrounding areas. In fact, in 2013, authorities demolished an unregistered building in the Jiangsu province in China — one that actually housed a hidden cockroach farm. As a result, over a million cockroaches escaped, and the cockroach farmer had to solicit the help of authorities in exterminating the pests.

Some cockroach species are endangered.

Although cockroaches are certainly prevalent throughout most of the world and likely won’t go extinct as a group anytime soon, some species of cockroaches still face the threat of extinction. Some species have a rather restricted natural habitat and face various threats such as habitat loss and the introduction of cockroach predators such as rats. As a result, some species are now endangered or critically endangered. One species, the Simandoa wood roach (Simandoa conserfariam), is now extinct in the wild.