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One of the most fascinating (and somewhat disturbing) facts in insect biology is that the cockroach is capable of surviving for days to weeks without its head. Unlike humans and other vertebrates, cockroaches have a different circulatory and nervous system that allows them to continue basic life functions even after decapitation.
Open Circulatory System
Cockroaches have hemolymph (insect “blood”) that flows freely in the body cavity rather than being pumped under pressure in veins.
When the head is cut off, blood does not gush out; it simply clots, preventing immediate death.
Breathing Mechanism
They breathe through spiracles—tiny openings in each body segment.
Oxygen directly diffuses into tissues without needing the head or brain.
Nervous System
Cockroaches have ganglia (mini-brains) distributed throughout their body.
This decentralized nervous system allows them to move and respond to stimuli without the head.
Energy Storage
They can survive on stored energy for days to weeks, so they don’t require immediate feeding through the mouth.
Although they can survive without a head, cockroaches eventually die because they cannot eat or drink. Dehydration and starvation are the main causes of death, usually within 1–2 weeks.
This adaptation demonstrates the resilience of insects and why cockroaches are among the oldest surviving species, existing for over 300 million years.
They are often used in entomology studies to understand survival strategies, nervous system distribution, and insect physiology.
Their ability to withstand extreme conditions also makes them common examples in biology exams and research.
Insect: Cockroach
Can survive 1–2 weeks without a head
Survival due to open circulatory system, spiracles, and distributed nervous system
Death occurs due to lack of food and water
👉 Correct Answer: Option 3 – Cockroach
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