The nocturnal insect known for its tough exoskeleton and ability to survive without a head is the cockroach.
Cockroaches are ancient, highly adaptable insects found on every continent except Antarctica. Their hard exoskeleton protects the body, while their flattened shape helps them squeeze into narrow cracks and hide during the day. Many species emerge at night to search for food, water and shelter.
The headless-survival fact is real, but often exaggerated. Cockroaches can remain alive after decapitation because they breathe through openings called spiracles along the body, rather than through a mouth and nose. Their circulation is also relatively low-pressure, so they do not bleed to death in the way a mammal might. A headless cockroach can survive for a limited period, but it eventually dies from dehydration or starvation.
Cockroaches are not uniquely indestructible: other insects can also survive decapitation, and they are not immune to radiation. Their reputation comes from a combination of biological resilience, rapid reproduction and the ability of some species to live on extremely limited resources.