Why Are Roaches So Hard to Kill?

Why Are Roaches So Hard to Kill?

The American Cockroach

Contrary to what its name suggests, the American cockroach is actually indigenous to Africa. In the 16th century, the creepy critters found their way onto ships traveling to the Americas and, once they landed, decided to begin infesting this new land. They are one of the largest species of cockroach and are masters of survival due to their vast genomes. Here are some of the factors that make them such incredible survivalists.

The Hunt for Sustenance

American roaches have 154 olfactory receptors. This means that they are extremely adept at sniffing out food sources even when food is scare. They also contain 544 gustatory receptors – which is more than any other insect known to be alive today – accounting for their ability to consume nearly anything as sustenance including dust bunnies, rotted foods, paper products, animal excrements, and even some poisonous plants and chemicals. They are virtually the garbage disposals of nature and can seemingly find sustenance anywhere. This unrestricted diet means that, while other insects or animals may expire from lack of food, it is exceedingly rare for a roach to run out of things to munch on.

Virtually Immune

Cytochrome P450 is a collection of specialized genes that are present in the American roach. Amazingly, as stated above these roaches are immune to certain toxins and poisons, which is all thanks to their Cytochrome P450s. These genes help provide detoxification enzymes that break down the toxins and protect the roaches. Meanwhile, their overall immune systems can also eliminate extremely harmful microbes and fungi, making the roaches nearly impervious to their surroundings no matter how unsanitary or dangerous to the average being.

Insane Survival

Squeamish be warned… roaches are rather disgusting creatures…

You may have heard that roaches can survive without their heads… and, creepily enough, this is true. They do not have a concentrated set of blood vessels in their heads or necks, so it they loose their head, they do not bleed out and as their bodies breathe without the use of their head, it is somewhat unneeded and the neck will actually heal over, allowing the body to continue to live. However, the roach will eventually expire around a week’s time due to the lack of being able to eat without a head. While they may not be able to regrow a decapitated head, when roaches molt in their younger stages, they are able to regrow limbs, antennas, and damaged parts such as their eyeballs.

You may have also heard that cockroaches can survive a nucelar apocalypse, and while this is not 100% true… the misconception is partially due to the true and tested resistance that cockroaches seem to have towards radiation. When exposed to radioactive waves in scientific tests, it was discovered that cockroaches are able to survive well beyond the limit for humans and even survive for longer periods of time following the exposure. However, all of the roaches did eventually succumb to the effects of the radiation and some even died during the tests when exposed to more extreme levels of radiation.

However… these tests were not deemed conclusive in regards to the survival of the species as a whole, as it was never tested to see if, prior to succumbing to the radiation, the roaches could produce viable eggs that could carry on more generations of the insect. If this is possible, it would ensure the continued survival of the species, thereby meaning that roaches could still potentially survive a nuclear blast… in a roundabout way…


Stanton, K. (2019) Could Cockroaches Survive a Nuclear Apocalypse?, Earth Sky. University of Melbourne. Available at: https://earthsky.org/earth/would-cockroaches-survive-nuclear-apocalypse (Accessed: May 2020).

Kim, G. and Polan, S. (2018) Why Cockroaches Are So Hard To KillYouTube. Science Insider. Available at: https://www.youtube.com/watch?v=KKYJf2DL1FM (Accessed: July 2020).