Cockroaches indeed can live without their heads. For weeks. Cockroaches don't have very much blood pressure in their open circulatory system and they breath through tiny holes throughout their body segments. So, cutting off their heads likely results in nothing more than a small blood clot — they end up starving to death after some weeks or getting eaten by a predator.
Buggy facts:
- The body doesn't only survive decapitation — the decapitated head does, too — for several hours, or longer if kept in the refrigerator and fed.
- About 4,000 species of cockroach roam the Earth. Humans normally are in contact with only about 30 of these species and regularly annoyed by four of the species.
- Scientists have discovered cockroach fossils as far back as 354 million years ago.
- The typical cockroach prefers dark areas and will flee from light, except for the Asian cockroach — it swarms toward light like a moth.
- With heads intact, many cockroaches can survive without food for as long as a month.