Lizard tail-loss rates on islands are not governed by longer life spans

We recently studied whether, on islands, predation or intraspecific aggression is the main driver of tail-loss, a common defense mechanism among lizards. We concluded the latter was the stronger driver (Itescu et al. 2017). Werner (2017) suggested that we failed to falsify an alternative hypothesis. He claims that on low-predation islands lizards live longer. Thus while tail loss is caused by predators, it accumulates over longer periods, resulting in overall higher tail-loss rates in populations experiencing weak predation. Here we test this hypothesis and three other arguments he presented, and fail to support them. We therefore adhere to our original conclusion that intraspecific aggression is the main driver of lizard tail loss on islands.