Fabre, the author of Souvenirs Entomologiques, was troubled by the question of what determines the duration of death feigning. I sometimes wonder what he might have discovered if he had access to modern technology. Do they play dead or not (frequency)? Or how long they continue to feign death (duration) varies enormously, not only between species but also within species. Even if an animal feigns death, it cannot continue doing so indefinitely. If it did, it would likely dry out under the scorching midday sun. More importantly, it could end up being eaten by a predator. For example, ants might carry a small insect feigning death back to their nest. There is a limit to how long death feigning can be maintained—and perhaps there is even an optimal duration for it. In this chapter, I provide an overview of 23 factors that influence the frequency and duration of death-feigning behavior. Among these factors are environmental and physiological ones, such as the time of day during which death feigning occurs—which puzzled Fabre—and temperature. If devices like incubators and precision balances had existed in his time, Fabre would no doubt have conducted all the experiments described in this chapter. I would like to dedicate this chapter to him.