Apparent death

This behavior is found for example in insects, spiders, birds and reptiles, particularly in snakes. In birds it is caused, among other things, by a forced supine position. Many stick insects can be covered with landscaped legs, to no longer be detectable by their similarity to plant parts for the predator. In laboratory rats is closed with respect to pain and anxiety reduction on the basis of Rigid Schreck on the efficacy of various drugs. and mechanisms of anxiety and fear processing

The Nightmare mortis insofar biologically appropriate that some predators respond primarily to the movement of the prey animal. On the other hand, escape rats only if in a given situation an escape can also be seen. In the other case it comes in addition to a rigid Schreck also to the release of endogenous opioids - regardless of whether the triggering stimulus a cat ( as innate enemy ), or an electric shock.

The possible adaptive value of fear mortis was experimentally demonstrated even with a beetle ( Rust Red Flour Beetle ) to a jumping spider species as a predator. The jumping spiders captured less flour beetles of experimentally induced breeding lines, who kept a longer shock rigid than. Those which previously solved this again