Facts About Cockroaches

Cockroach Laying Egg Case (Sac) - Creative Commons
Cockroach Laying Egg Case (Sac)
Creative Commons

There are many fun facts about roaches. Yes, cockroaches are rather nasty and carry bacteria. but not all cockroaches are pests. These insects do play a role in nature, but when they get into your home, they are definitely pests that bring health hazards to humans The following Roach Facts are interesting and will give you more insight into these creatures that have survived in great numbers for 300 million years.

Cockroach Facts


Fact: What’s With These Common Cockroach Names?
The most common roaches in America are the German and American species. Strange since neither of those roaches originated in America. Nor did the German Roach originate in Germany. Scientists believe it likely entered Europe from Southeast Asia. The American Roach came from North Africa and likely entered on ships during the slave trade.

Here’s what’s funny. In Germany, the German Cockroach is called the Russian Cockroach. But in Russia, it is called the Polish Roach. There are thousands of roach species, but most of them do not even have a common name other that those scientific names that no one can even pronounce yet alone spell.

Fact: Purpose of A Cockroach To Nature
What are roaches good for? Of the over 4,000 species of roaches in the world, only about 40 exist in the United States and most of those are almost indistinguishable from the most common roaches which are the German and American species.

Nature intended roaches as scavengers to recycle organic matter. They eat anything from dying plant life to corpses of other animals including other roaches. They are a primary food source of birds, lizards, spiders and small mammals. Therefore they are important to balancing the food chain.

However, their most valuable role is in the forests and caves away from humans. It is true that very few types of roaches are nuisance pests. The German and American Roaches however have become serious pests to home owners, restaurants, grocery stores and commercial buildings that are highly targeted places for roaches to infest.

The German and American Roaches seem to have lost their appetites for decaying plant life in favor of food and water sources found in your house. They have become serious pests spreading bacteria everywhere they touch. Since it is impossible to trap them and return them deeply into forests, there is not much choice but to eradicate those that do invade homes.

Fact: Cockroaches Can Live For Weeks Without Its Head

It’s true. A cockroach does not have blood pressure so therefore missing its head does not lead to uncontrolled bleeding and its blood does not carry oxygen to its tissue. “Breathing” is done by spiracles located on each of its body segments and through a set of tubes, air is delivered to each body cell. Its brain does not control breathing.

The typical roach can go about a month without eating and up to a few weeks without water. So, they could live those durations even without their head. Eventually they would die of starvation or dehydration.

Fact: Do Roaches Bite?

Cockroaches are omnivore which means it will eat anything edible. That could include vegetation or meat. The will also eat glue, wallpaper paste and even toothpaste. So, if everyone is completely still while sleeping, it is possible they may nibble on people. There have examples where people have gone to the emergency room complaining of roach bites.

But there is no scientific evidence to prove this. Only those that have been bitten and actually seen it happen would really know for sure. Roaches sense people and will escape. They are not aggressive. So the jury is still out on the “does a roach bite people” issue.

Fact: Cockroach Blood is Not Red

Cockroach blood does not carry oxygen and is not red because there is no hemoglobin. Its blood stream carries no oxygen at all to its body organs. Instead, oxygen is carried directly to cells through a system of tubes located on each body segment.

Males and larval females have colorless blood. Adult females, which produce eggs have blood that is a slightly orange color caused by the protein vitellogenin which is produced in its liver. The protein is carried through the blood to the ovary. That protein is similar to the yolk of a chicken egg which serves as a vitamin like molecule which is needed by embryos to help develop it normally.

Fact: How Roaches Breathe
Roaches do not have lungs and therefore do not use their mouths to breathe oxygen. Like all insects, they collect oxygen through a system of tubes called tracheae. The tubes are connected to spiracles attached to body segments except the head.

These tracheal system branches much like a very small tree where tube limbs progressively branch to increasingly smaller tubes which supply cells with oxygen and displace carbon dioxide. Also see “Can Roaches Live Without A Head“. This is one of the reasons that a cockroach can live for a few days and even up to a month without its head.

Fact: Not All Roaches Are Household or Restaurant Pests
Of the over 4,000 species of cockroaches worldwide only about 30 are pests and threats to humans by infesting homes, restaurants, hospitals and grocery stores. The overwhelming majority of roach species hangout in remote forests, caves and wide open spaces. They are scavengers that will eat most anything from decaying plant life to corpses of smaller animals and even those of other roaches.

In America, the most common pest roaches are the German, American, and Asian varieties. German cockroaches most always infest indoors and are the most common roach found in homes. They are prolific breeders and can infest a building at a rapid pace. American roaches prefer to nest outdoors but close to commercial establishments and homes. Although they invade homes looking for food and water, they generally will return to outdoor nests.

Fact: Some Cockroaches Can Fly
Some roaches can fly well, some think they can fly and other species can’t fly at all. Most roaches however do have wings although they may not function as a flying instrument. An example is the German roach and Oriental roach that do not fly.

American roaches can use its wings to glide from elevated places to lower places. Among the roaches in the United States that do fly are the Smoky Brown and Wood Roaches that can easily fly from trees onto houses. Other roaches that can fly include the Australian, Cuban and Asian species.

Fact: How Roaches Breed

Very quickly. Although some roaches can give live birth, cockroach females create egg cases. The number of eggs in a case depends upon the species. The German roach is one of the most prolific breeders and responsible for the highest level of home infestation.

A female German roach can produce up to 8 egg cases in her adult lifetime of about a year. Each case averages 30 to 40 eggs and more. She carries the case at the end of her abdomen and drops the case just prior to hatching of the eggs. Development from egg to adult takes about 3 to 4 months. In average conditions, a German roach female can produce over 300 offspring during her short lifetime.

The number of new roaches created by just one female is mind- boggling. Assuming that half of the 300 offspring produced in about one year are females, that means 150 more females will be laying more egg sacs every few months. The exponential rate of growth is simply astounding and is the reason a German cockroach can infest a home so rapidly.

Fact: Diseases and Bacteria Roaches Carry

Roaches do provide a value to nature and humanity. As scavengers. they clean-up waste. And decaying matter including plant life and dead small animals. Roaches are not aggressive and pretty docile.

However. When roaches invade our homes, the are a definite health hazard to people. They eat rotting food, pickup bacteria and place it on the things we use and touch on a daily basis. Like counter tops, knives, forks, spoons. dishes, exposed edible fresh foods, postage stamps, sinks, cabinets, beds, couches, cribs, and almost any where they go looking for food, water, and shelter.

They even deposit their feces along their hunting trails. The disease- causing bacteria roaches pickup during expeditions doesn’t seem to adversely effect them. Perhaps that’s why they’ve existed in such overwhelming numbers for over 300 million years.

Across the world they have carried and transmitted many diseases to humans including salmonella, dysentery, hepatitis, typhoid and cholera. In America, we are able to avoid most of the serious diseases. However, salmonella is the cause of some serious food-poisoning. And the dried waste and molded exoskeletons of roaches negatively effect asthmatics and those with severe allergies.

We have no choice but to protect our families when they enter our homes. They must be destroyed when they invade our territories. Of course, our goals should first be preventive approaches such as sealing entry points and practicing good sanitation. When that fails, we have to resort to using insecticides that are the safest, yet productive.

Fact: Comparing Sizes of Common Roaches

Illustration That Compares Different Types of Roaches in America

Chart Comparing Common Types of Roaches

  • A. German roach, or Croton bug, Blattella germanica (length 9/16 inch).
  • B. American cockroach, Periplaneta americana (length 1 3/8 inches).
  • C. Australian cockroach, Periplaneta australasiae (length 1 1/4 inches).
  • D. Wingless female of the Oriental roach, Blatta orientalis (length 1 1/8 inches).
  • E. Winged male of the Oriental roach (length 1 inch)