1. Introduced predators account for a large part of the extinction of endemic insular species, which constitutes a major component of the loss of biodiversity among vertebrates. Eradication of alien predators from these ecosystems is often considered the best solution.
2. In some ecosystems, however, it can generate a greater threat for endemic prey through what is called the ‘mesopredator release’. This process predicts that, once superpredators are suppressed, a burst of mesopredators may follow which leads their shared prey to extinction.
3. This process is studied through a mathematical model describing a three species system (prey–mesopredator–superpredator). Analysis of the model, with and without control of meso- and superpredators, shows that this process does indeed exist and can drive shared prey to rapid extinction.
4. This work emphasizes that, although counter-intuitive, eradication of introduced superpredators, such as feral domestic cats, is not always the best solution to protect endemic prey when introduced mesopredators, such as rats, are also present.