A cockroach can live for over a week without its head.

Cockroaches are built very differently from humans. We have one big brain that controls everything, but a cockroach has clusters of nerves called ganglia spread throughout its entire body. These mini-brains allow the body to keep standing and moving even if the head is gone.They also have an open circulatory system. This means their blood doesn't pump through high-pressure veins like ours. When a cockroach loses its head, its neck simply clots and seals up, so it doesn't bleed out. Dr. Joseph Kunkel from the University of Massachusetts has studied this and found that their breathing is totally automatic.Instead of lungs, they use a network of tubes called tracheae. These tubes connect to little openings on their sides called spiracles. Oxygen goes straight from the air into their tissues without needing a mouth or a nose to help. The only reason the headless cockroach eventually dies is dehydration. Without a mouth, it has no way to swallow water. In some cool lab experiments, scientists found that if they kept the air very damp, a headless cockroach could actually stay alive for several weeks!