So one of our readers asked us this question the other day: Why do Cockroaches die on their backs so frequently?

Around my school I often avoid stepping on a dead roach, but for some reason these dead roaches are always on their backs. What would compel an insect with a microscopic brain to flip over before they die of natural or possibly otherwise causes? It seems a pointless habit and yet every dead cockroach I have ever seen does that. Is there an evolutionary advantage to such a strange occurrence?


There are two basic reasons. Cockroaches have a slightly rounded and greasy back, and a flat body that helps them squeeze and hide in narrow cracks and crevices. Their long legs give them a high center of gravity, meaning they carry most of their weight around their backs. When a cockroach is dying of old age, its high center of gravity pulls its back toward the floor, and its rounded back and weakened muscles prevent it from righting itself, particularly on smooth surfaces.

The insecticides we use to kill roaches can have the same effect. Most of these insecticides are neurotoxins – poisons that can trigger tremors and muscle spasms, eventually causing the cockroach to flip on its back. A healthy cockroach can easily right itself, but the tremors, lack of muscle coordination and, again, the rounded back and high center of gravity cause the intoxicated cockroach to get stuck that way.

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Last Update: September 1, 2016

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