The Myth of the Indestructible Cockroach
During the Cold War, anti-nuclear activists quickly spread the story that placed cockroaches as the only survivors of an atomic exchange between the United States and the Soviet Union. The natural resistance of cockroaches, coupled with their extraordinary adaptability, cemented that belief, but how true is it? Several studies have been conducted on the matter, and even an episode of MythBusters explored the topic…
Cockroaches! For some people they represent a traumatic encounter, and for others they are an everyday thing. The latest fumigation techniques can eliminate them in record time, but if there is an intact path that allows them to return, they will. This particular persistence of cockroaches has only reinforced their indestructibility profile, to the point that imagining them as the only survivors of a nuclear attack is quite common. Now, the question is: to what extent is that true? Basically, what we are interested in is their resistance to radiation, and the first studies date back to 1963.
What the Science Says
That year, doctors Ross and Cochran of the Virginia Polytechnic Institute found that the German cockroach (Blattella germanica) showed signs of sterility at 3,200 rads (or 32 grays), while a dose of 6,400 rads (64 grays) killed 93 percent of the population.
A bit closer in time, the MythBusters team decided to conduct a similar experiment, applying three different levels with cobalt-60. After monitoring their progress for thirty days, the mythbusters discovered that 50 percent of the cockroaches exposed to 1,000 rads were still alive. At 10,000 rads, the number dropped to 10 percent, and at 100,000 rads none survived. As a reference, we must not forget that 1,000 rads can kill a person in just ten minutes.
The Bottom Line
In summary: from a biological point of view, they are not indestructible; however, the available numbers suggest a radiation resistance 14 times higher than that of humans for cockroaches in the best case. Beyond the variables among different types of cockroaches, the truth is that they are far from being the most resistant creatures: the common fruit fly needs 64,000 rads to be annihilated, and the extremophile Thermococcus gammatolerans can tolerate up to 3 million rads. For comparison, and to do your own math, here is the following information, taken from the Atomic Bomb Museum.
Doses at Hiroshima and Nagasaki
Estimated Gamma Ray Doses in Air
- Hiroshima: 10,300 rads
- Nagasaki: 25,100 rads
Estimated Neutron Doses
- Hiroshima: 14,100 rads
- Nagasaki: 3,900 rads
