The slow-fast continuum is known to structure variation in life-history strategies across species. Within populations, it is also assumed to structure individual life histories, yet evidence of its existence remains unclear. We formally assessed the presence of a slow-fast continuum of life histories both within populations and across species using detailed individual-based data for 17 bird and mammal species with contrasting life histories. We estimated adult lifespan, age at first reproduction, breeding frequency and fecundity, and identified the main axes of variation using Principal Component Analyses. The slow-fast continuum was the main axis of life-history variation across species, but within populations individual variation did not follow the slow-fast continuum in any species. This suggests that individual life histories are neither slow nor fast, but rather follow an idiosyncratic pattern across species because of relative differences in the importance of processes such as stochasticity, density dependence, and variation in individual performance.

This dataset was collected through the long-term monitoring of individuals from 17 mammal and bird species. It comprises individual measurements of life-history traits (age at first reproduction, adult lifespan, breeding frequency and fecundity) as well as individual generation time.

The dataset in a Rdata file, which can be open in R.