A cockroach CAN live without its head.
More Info: It won't live out its natural life span, but a cockroach can live for several weeks without its head.
Though it seems impossible that any living creature can survive decapitation, the anatomy of a cockroach allows it to exist for a short while without its head. Several factors make this possible.
The loss of head for most animal species would result in immediate death for a variety of reasons. The list is extensive and includes loss of air to the lungs, blood loss, and the severance of the spinal cord cutting off the brain activity that dictates life supporting body functions.
The Cockroach's Unique Anatomy
Respiratory System: The cockroach breathes through spiracles located along its back making it possible for it to breathe even without a head.
Circulatory System: The cockroach has an open circulatory system and seems to have a unique clotting ability when injured. In experiments, researchers found that the cockroach's neck will simply clot and seal following decapitation.
Nervous System: Though a portion of the cockroach's brain is located in its head, the rest is actually scattered along the vertical portion of its body helping the body to continue to function even without a head.
How Long Can the Cockroach Live without Its Head?
Though the cockroach will ultimately die due to lack of food and water since it does need its head to eat, it also has the unique ability to survive for weeks on one meal and more than a week without water.