Why do a cockroach survive a atomic bomb?

Answer 1

Not all of them survive! But they would survive better than we would. There organism - body build - is smaller than ours and therefore making us more suseptable to the radiation than the cockroach

They say that a cockroach will live through a atomic bomb, but if the atom bomb was to hit the cockroach or if it were to go off above the cockroach it would did nothing will live around where the bomb goes off even a cockroach.

I would like to propose what I think is a better answer from Wikipedia :

Cockroaches do indeed have a much higher radiation resistance than vertebrates, with the lethal dose perhaps 6 to 15 times that for humans. However, they are not exceptionally radiation-resistant compared to other insects, such as the fruit fly.[21] The cockroach's ability to withstand radiation better than human beings can be explained through the cell cycle. Cells are most vulnerable to the effects of radiation when they are dividing. A cockroach's cells divide only once each time it molts, which is weekly at most in a juvenile roach. Since not all cockroaches would be molting at the same time, many would be unaffected by an acute burst of radiation, but lingering radioactive fallout would still be harmful

http://en.wikipedia.org/wiki/Cockroach#Hardiness

Answer 2

That's and old myth that wont go away. High radiation kills cockroaches.

Answer 3

They can't. However like all insects they have a higher LD50 (lethal dose 50% , the dose that kills 50% of those exposed) for ionizing radiation than mammals do.