Do big-brained animals play more? Comparative analyses of play and relative brain size in mammals

It has been hypothesized that play is more likely to be present in larger b rained species. We tested this hypothesis in mammals using independent cont rasts, a method that controls for phylogenetic relatedness. Comparisons acr oss 15 orders revealed that the prevalence and complexity of play was signi ficantly correlated with brain size, with larger brained orders having more playful species. Three orders, Rodentia, Marsupialia, and Primates, were u sed for within-order comparisons among species and, where possible, among f amilies. The comparisons were not significant for rodents or primates, and those for marsupials yielded inconsistent results. Therefore, although a st rong relationship is present at the highest taxonomic level of comparison, it diminishes or evaporates at lower level comparisons.