In March of the present year, the journal Science published a study that proposed a causal relationship between the body size of insular species and their risk of extinction. According to the study's authors, dwarfism or gigantism in these species made them more vulnerable. Now, Meike Köhler and Salvador Moyà-Solà, heads of group at the Institut Català de Paleontologia Miquel Crusafont (ICP) and ICREA researchers, have published a reply article in which they argue that this relationship is not causal and alert against a misinterpretation of the characteristics of insular endemisms could lead to serious mistakes in estimating their extinction risk.