# Coevolution of relative brain size and life expectancy in parrots The R code needed to replicate results from the article: ``` Smeele SQ, Conde DA, Baudisch A, Bruslund S, Iwaniuk A, Staerk H, Wright TF, Young AM, McElreath MB, Aplin L. in prep. Coevolution of relative brain size and life expectancy in parrots. ``` ------------------------------------------------ **Abstract** Parrots are well-known for their exceptionally long lives and cognitive complexity. While previous studies have demonstrated a correlation between longevity and brain size in a variety of taxa, little research has been devoted to understanding this link in parrots. Here we employed a large-scale comparative analysis that investigated the influence of brain size and life history variables on patterns of longevity. Specifically, we addressed two hypotheses for evolutionary drivers of longevity: the Cognitive Buffer Hypothesis, which proposes that increased cognitive abilities enable longer life spans, and the Expensive Brain Hypothesis, which holds that the increase in life span is caused by prolonged developmental time of and increased parental investment in, large brained offspring. We estimated life expectancy from detailed zoo records for 133,818 individuals across 244 parrot species. Using Bayesian structural equation models, we found a consistent correlation between relative brain size and life expectancy in parrots. This correlation was best explained by a direct effect of relative brain size. Notably, we found no effects of developmental time, clutch size, or age at first reproduction. Our results provide support for the Cognitive Buffer Hypothesis, and demonstrate a principled Bayesian approach that addresses data uncertainty and imputation of missing values. ------------------------------------------------ **The folders contain:** ANALYSIS: - CODE: the code to replicate results - DATA: raw data - RESULTS: intermediate results and figures NOTE: Some data contains sensitive information (zoo records) and can therefore not be made available even after publication. Processed data will be made available. ------------------------------------------------ **Maintainers and contact:** Please contact Simeon Q. Smeele, , if you have any questions or suggestions.