Cockroaches are widely known as small, ugly critters. But these ancient survivalists have adapted in amazing ways over hundreds of millions of years. Let’s take a look at some of the most important cockroach facts, and how they matter to you.

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What Are Cockroaches?

Illustration of a cockroach field guide, opened to an introductory page.

Cockroaches are insects in the Blattodea order. They’re related to termites and once, deep in the distant past, the two insects shared a common ancestor. Scientists have discovered cockroach fossils that date back over 320 million years to the Triassic period and earlier. Talk about walking with dinosaurs.

There are well over 4,000 species of cockroaches living around the world. Most of them don’t live near or interact with humans but the few that do have become serious household and commercial pests.

Why are they called “cockroaches”?

“Cockroach” is actually an English mispronunciation of their Spanish name, cucaracha, that stuck. Have you heard the catchy tune “La Cucaracha?” It’s a Spanish folk song that’s been sung for centuries—and now you know what it’s really about.

The “Blatta” in Blattodea is Latin for “an insect that shuns the light.” Roaches belong to this family because they spend most of their time hiding in the dark.

Facts About Cockroach Biology

Illustration of a cockroach field guide turned to a page about cockroach biology

Life Cycle: How Cockroaches Reproduce

Cockroaches are egg-laying insects but they don’t lay their eggs like birds in a nest.

Female roaches lay eggs inside an egg case, called an ootheca. American cockroaches typically lay about a dozen eggs in an egg case while German cockroaches lay as many as 50 eggs in each. That’s a lot of baby cockroaches—up to 400 from a single female in her lifetime!

Male roaches of some species stick around to tend to the young after they hatch. Not only do the males scavenge food but they go as far as eating bird feces to take in vital nitrogen and bring it back to their offspring.

Why are baby cockroaches white?

Cockroach nymphs molt repeatedly as they mature. Each time, they shed their old exoskeleton and grow a new one. But during the short time in between, they appear white because they’re lacking that hard outer covering that darkens as it hardens with time.

What’s a cockroach’s lifespan?

Most cockroaches live for less than a year. The adult lifespan of a cockroach varies between species. An adult German roach only lives 20 to 30 weeks. However, an adult American cockroach can live for well over a year.

How do cockroaches breathe?

Cockroaches breathe very differently from humans. Instead of using their head to breathe, they breathe through tiny pores in their body segments called spiracles. A cockroach’s exoskeleton features a number of these holes that let them take in air and absorb oxygen directly into their organs.

This respiratory system gives them an amazing superpower— a cockroach can live a week without its head! (So when battling cockroaches, think the opposite of zombies—_don’t_ aim for the head!)

They also have an open circulatory system, which lets their blood travel through a system of connected spaces instead of on a closed track. A headless cockroach can still breathe and circulate blood; its undoing is actually that it can no longer drink water (or eat) without its head – thus dying from dehydration .

By Land or by Air: How Fast Are Cockroaches?

Cockroaches are crazy fast runners. Their powerful rear legs can propel them up to 1.5 meters (50 body-lengths) per second. Translated into human sizes and distances, that’s like running 200 miles per hour! (The Oriental cockroach is an exception—it’s noticeably slower than other species.)

Quite a few species of cockroaches fly but most of them do it awkwardly and seldomly.

For example, American cockroaches can fly but usually don’t. On the other hand, Asian cockroaches are relatively strong fliers. The unique green Cuban cockroach is probably the best flier of them all. It’s nicknamed the “banana cockroach” because of its tendency to fly around among the branches of banana trees.

Are cockroaches attracted to lights?

Some cockroaches avoid lights, hiding in dark places all day and scavenging at night. Others, however, are strongly attracted to lights. Flying cockroaches—like the smoky brown cockroach—are especially drawn to lights and, often, they fly through open windows toward TV screens and ceiling lights.

Can cockroaches swim?

A cockroach’s stick-like legs and delicate wings aren’t the ideal paddles for swimming through water. That doesn’t mean getting rid of one is as simple as flushing it down the drain, though.

A cockroach can hold its breath for up to 40 minutes! There’s a good chance it’ll come out fine at the other end and won’t mind a bit that it’s wound up in a sewer. After all, sewage is among the many things that make up a roach’s diet.

Why is it so difficult to crush a cockroach?

It turns out, a cockroach’s hard exoskeleton is also quite flexible or leathery. You can see the joints in it if you dare to look closely. Scientists studying these bugs used a machine to squish them with 900 times their body weight. They survived. More than that: they still ran at full speed, as if nothing had happened.

Where Cockroaches Live: Inside, Outside and Around the World

Illustration of a cockroach field guide, opened to a page about where cockroaches live.

Most cockroaches live outdoors. They crawl among the fallen leaves on forest floors or build colonies inside tree hollows. They burrow, climb and fly to find habitats and, sometimes, that search leads them into buildings.

Are cockroaches really everywhere?

Cockroaches have a reputation for being expert survivalists but there’s one place on Earth they haven’t been able to colonize: Antarctica. Though it’s possible a few roaches have stowed away on ships and sailed the seas to that southernmost continent, they haven’t yet been able to adapt to its harsh, freezing conditions. But don’t ever count a cockroach out.

Do cockroaches build nests?

A cockroach “nest” isn’t like a bird’s nest. It’s typically just a hole, box or other dark, out-of-reach place where the roaches hide and reproduce. It will probably contain molted exoskeletons, droppings and a few dead roaches.

Some cockroaches live with ants.

Our homes aren’t the only ones cockroaches like to invade. There are at least 2 species of wood cockroaches that have been seen living with ants!

Researchers have found the western wood cockroach and the Boll’s wood cockroach living in anthills among the ants. It’s the nymphs of both species that seem to hide in the anthills during the day and leave to find food at night.

That’s despite the fact that cockroaches occasionally eat ants and other insects (even other dead roaches)!

The Cockroach Diet: Is There Anything They Won’t Eat?

Illustration of a cockroach field guide, opened to a page about cockroach's diet.

Short answer: no. If it’s edible, a cockroach will probably eat it. Anything we eat—from meat and vegetables to sugar and grease—is fair game for a hungry roach.

Cockroaches are omnivores, meaning they eat both plants and animals. They’re also detritivores—organisms that eat decaying organic material. Rotten fruit, dead leaves and even animal waste are all on the menu for cockroaches.

It sounds gross, but a cockroach’s unpleasant eating habits make it an important part of its ecosystem. Roaches and other detritivores break down the dead plant and animal material and help return nutrients to the soil.

Can a cockroach survive without water?

Cockroaches can live a month without food. However, they can’t live a long time without water. Cockroaches are sensitive to dehydration and changes in humidity. That’s why they’re frequently spotted in bathtubs and sinks.

Cockroaches can go for a month without eating but they won’t survive longer than a week without water (depending on what they are feeding on, they may get some of their water from their food).

Cockroaches and Us: Friendly or Dangerous?

Illustration of a cockroach field guide, opened to a page about cockroach dangers.

Although only a few cockroach species live among humans, those few can become major problems. The German cockroach is one of the most widespread household pests in the world, taking over city apartment buildings with ease. Once inside, roaches are destructive and potentially dangerous due to their ability to spread disease and filth.

Cockroaches can spread disease.

One of the more disturbing cockroach facts has to do with disease.

Because like rats and certain other kinds of pests, they can transmit diseases to people. Roaches crawl through sewers, drain pipes, gutters and piles of decaying material as they scavenge for food. If they make it into your house, they’ll spread the bacteria they’ve picked up on countertops, cooking surfaces and any food you’ve left out.

One of the adaptations that makes a roach so resilient is its body’s natural ability to produce antibiotics. That saves them from the harmful bacteria they could transfer to us.

Do cockroaches cause allergies?

The negative effects of roaches go beyond ruining food. Cockroach infestations can trigger people’s allergies. The main contributors to allergic reactions are the molted exoskeletons and roach droppings that they leave behind. People with asthma are especially sensitive to cockroach allergens.

Myths and Other Facts about Roaches

Illustration of a cockroach field guide, opened to a page about cockroach myths.

Can cockroaches survive a nuclear explosion?

Probably not. But cockroaches can survive intense levels of radiation.

“Rems” is the unit of measurement scientists use to describe radiation damage to the human body. 800 rems are fatal to humans. Meanwhile, cockroaches can withstand up to 100,000 rems. The thing is, a nuclear explosion creates a lot of heat too. Cockroaches are strong creatures but they can’t survive a temperature of 10,000 degrees Fahrenheit.

Do cockroaches like beer?

Cockroaches do like alcoholic beverages, especially beer! In a 2006 study, beer placed in a jar with bread attracted more cockroaches than any other bait. Roaches are drawn to beer by the sugar it contains, not for its alcohol content.

Do cockroaches crawl into people’s ears?

It’s extremely rare but… unfortunately… yes, they can. Your ears happen to be dark, humid and tiny—the 3 ingredients roaches look for in a habitat. Cockroaches may also see earwax as a food source. Again, cockroaches almost always stay away from people, so it’s probably best to forget about this fact as soon as possible.

Do cockroaches smell bad?

You already know about cockroaches’ poor hygiene. The places they venture don’t leave them smelling fresh. Cockroaches also produce chemicals that have a foul odor. When roaches touch food, they leave that smell behind—a good thing, since you definitely don’t want to eat a cockroach’s leftovers!

Do cockroaches bite?

Cockroaches can bite but they almost never do. There’s simply no reason for them to bite a person; they don’t feed on blood like mosquitoes and they’re not predators. On the fight or flight spectrum, cockroaches are very much flight when they come face to face with a towering human.


Despite all of their amazing adaptations, it’s important to get rid of cockroaches quickly if they’ve come into your house.

We’ve got all of the information you need to start an effective pest control plan, from where they hide to what they eat and how to keep them away for good.

Explore our in-depth guides to all things cockroaches and discover even more amazing cockroach facts while you learn how to keep your house cockroach-free.

Written by Andrew Martin, Reviewed by Helene Steenkamp, PhD.

Andrew Martin

Andrew Martin


Andrew writes for, and along with his daughter, publishes Cockroach Facts. You can read more about him here.

Helene Steenkamp, PhD.

Science Editor

Helene is a Namibian born South African citizen with a great love for nature and its intricacies. She completed a PhD in molecular phylogenetics at the University of Pretoria, South Africa in 2011, and has since worked as a postdoctoral researcher in this field at the University as well as the National Zoological Gardens of South Africa.

She has published several peer reviewed scientific articles with the use of genetic, taxonomic and phylogenetic tools, specializing in Entomology, taxonomy, zoonoses, epidemiology and bacterial & viral genetics.

These days, she is a stay-at-home-mother of two lovely boys, with whom she loves to explore nature from a different point of view. She also works as a freelance writer, editor and researcher for all things science.

You can learn more about our contributors here.


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  5. Dell’amore, Christine (2010) Cockroach Brains May Hold New Antibiotics. National Geographic. Retrieved from
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  1. Will Oothecas die without oxygen or might they stay dormant and come to life when oxygen returns? I’m relocating and don’t want to take them with me. I will use vacuum pack bags instead of boxes for as much as I can. And not all the furniture is coming with me. If I do anything I can to shake out eggs from books, pictures, was clothes… Will it be safe to open vacuum packed items in 30 days without worry if I missed a store away)

    • Andrew

      Hi Lauren, the question I’d have is whether there would be any air left in the bag or in the oothecae themselves. Cold would kill them, though. Is there a way you could put your filled vacuum bags in a freezer for a few days or fill them with a blast of Co2 from a soda charger? Extreme cold would effectively kill the eggs.

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