Data from: Large-brained frogs mature later and live longer

Brain sizes vary substantially across vertebrate taxa yet the evolution of brain size appears tightly linked to the evolution of life histories. For example, larger-brained species generally live longer than smaller-brained species. A larger brain requires more time to grow and develop at a cost of exceeded gestation period and delayed weaning age. The cost of slower development may be compensated by better homeostasis control and increased cognitive abilities, both of which should increase survival probabilities and hence lifespan. To date this relationship between lifespan and brain size seems well established in homoeothermic animals, especially in mammals. Whether this pattern occurs also in other clades of vertebrates remains enigmatic. Here, we undertake the first comparative test of the relationship between lifespan and brain size in an ectothermic vertebrate group, the anuran amphibians. After controlling for the effects of shared ancestry and body size, we find a positive correlation between brain mass, age at sexual maturation, and lifespan, across 40 species of frogs. Moreover, we also find that the ventral brain regions, including the olfactory bulbs, are larger in long-lived species. Our results indicate that the relationship between life history and brain evolution follows a general pattern across vertebrate clades.脊椎动物各类群间脑容量差异显著，而脑容量的演化似乎与生活史的演化紧密相关。例如，脑容量更大的物种通常寿命长于脑容量较小的物种。脑容量更大的大脑需要更长的生长发育时间，其代价为妊娠期延长与断奶年龄推迟。发育迟缓带来的代价，可通过更优的内稳态（homeostasis）调控与增强的认知能力得以补偿——这两者均能提升生存概率，进而延长寿命。迄今为止，寿命与脑容量的这一关联在恒温（homoeothermic）动物中已得到充分证实，尤以哺乳动物为甚。目前尚不清楚这一模式是否同样存在于脊椎动物的其他演化支中。本研究首次对变温（ectothermic）脊椎动物类群——无尾两栖类（anuran amphibians）中的寿命与脑容量关联开展比较检验。在控制共同祖先与体型的影响后，我们对40种蛙类的分析显示，脑质量、性成熟年龄与寿命三者间呈正相关关系。此外，我们还发现长寿物种的脑腹侧区域（包括嗅球（olfactory bulbs））体积更大。本研究结果表明，生活史与脑演化之间的关联在脊椎动物各演化支中遵循通用模式。