Data for: Phylogenetically controlled life history trait meta-analysis in cetaceans reveals unexpected negative brain size and longevity correlation

The identification of patterns in trait evolution is essential to
understand the interaction of evolutionary forces, and provides useful
information for species management. Cetaceans are a phylogenetically
well-resolved infraorder that exhibit distinct trait variation across
behavioural, molecular and life history dimensions, yet few researchers
have applied a meta-analytic or comparative approach to these traits. To
understand cetacean trait evolution, we used a phylogenetic generalised
least squares approach to examine the cognitive buffer hypothesis (CBH). A
large brain should buffer individuals against environmental challenges
through increasing survival rates, and a longer lifespan should buffer
individuals against the cost of extended development for larger brains
according to the CBH, leading to an expected positive correlation between
brain size and lifespan. In contrast to this expectation, previously
observed in taxa including primates, we found a negative correlation
between brain size and lifespan in cetaceans. This suggests cetaceans
experience selective pressures different from most other mammals in these
traits but may be more similar to some social mammalian carnivores that
display alloparenting. We also provide a comprehensive dataset to explore
additional aspects of trait evolution but which would greatly benefit from
studies on behavioural ecology across cetaceans and increased focus on
data-deficient species.