Popular culture loves to joke that cockroaches would be the last survivors on Earth if humanity ever faced a nuclear apocalypse.
The 2008 Pixar film Wall-E even leaned into the myth, giving the lonely trash-collecting robot a pet cockroach as his only companion in a ruined world.
But how much truth is there to this story? Could cockroaches really survive the aftermath of a nuclear explosion when humans and most other animals could not?
The myth partly comes from rumors that insects thrived in Hiroshima and Nagasaki after the atomic bombings.
However, Professor Tilman Ruff of the University of Melbourne, a Nobel Laureate who studies the health and environmental effects of nuclear weapons, says he has never seen evidence of cockroaches scuttling through the rubble.
Flies and other insects certainly appeared, but they too would have been affected by radiation and destruction.
In 2012, the U.S. TV show Mythbusters tested the claim by exposing cockroaches to radioactive material.
The results showed cockroaches could withstand more radiation than humans, but at very high levels they all eventually died.
Other studies suggest that while cockroaches are six to 15 times more resistant to radiation than humans, they are not the most resistant insects. Fruit flies and some ants, especially those that nest deep underground, would likely outlast cockroaches in a post-apocalyptic scenario.
Cockroaches have earned their reputation for toughness in other ways. They breed rapidly, produce large numbers of eggs, and are hard to kill with common pesticides.
Their flat bodies allow them to squeeze into cracks and escape danger, and when threatened they release an unpleasant smell to deter predators.
These traits have made them extremely successful in human environments and contribute to the belief that they can survive anything, even nuclear war.
But survival after a nuclear apocalypse involves more than just withstanding radiation. Food would become scarce. Cockroaches feed on organic waste, and while they could survive for a time on decaying bodies and debris, eventually their food sources would run out.
As Professor Mark Elgar from the University of Melbourne points out, without humans or other animals producing waste, cockroaches would struggle to thrive.
Radiation itself would also be devastating. Nuclear explosions release ionizing radiation, which damages DNA, kills cells, and causes long-term health problems like cancer and cardiovascular disease. Radioactive materials accumulate in the environment, recycling through soil, water, and the food chain.
Animals at the top of the food chain can end up with radiation levels thousands of times higher than in their surroundings. Evidence from Chernobyl shows that every organism—bacteria, fungi, insects, birds, and mammals—suffers effects, including shorter lifespans, reduced fertility, genetic mutations, and higher rates of disease.
While insects may endure longer than humans in controlled laboratory conditions, the scale of destruction from a real nuclear event is far greater.
The environment would be poisoned, ecosystems shattered, and food chains disrupted. In that scenario, even cockroaches would not ultimately survive.
So while cockroaches are hardy creatures that may outlast humans in certain circumstances, the idea that they could inherit a post-nuclear Earth is more myth than fact. In reality, very little—if anything—would survive a full-scale nuclear apocalypse.
