Born with an advantage: Early life and maternal effects on fitness in Columbian ground squirrels

Lifetime fitness and its determinants are an important topic in the study of behavioural ecology and life-history evolution. Early life conditions comprise some of these determinants, warranting further investigation into their impact. In humans, for example, babies born lighter tend to have lower life expectancy and fewer offspring than heavier ones. Similarly, some of these life-history traits are passed on to offspring, with lighter-born females giving birth to lighter offspring. We investigated how weight at weaning, the relative timing of birth in the season, maternal weight, and maternal age affected the longevity and lifetime reproductive success (LRS) of female Columbian ground squirrels (Urocitellus columbianus). We hypothesized that early life conditions such as offspring weight would not only have lifetime fitness consequences but also intergenerational effects. We found that weight at weaning had a significant impact on longevity, with heavier individuals living longer. The ..., , , # Born with an advantage: Early life and maternal effects on fitness in Columbian ground squirrels

[https://doi.org/10.5061/dryad.9s4mw6mpx](https://doi.org/10.5061/dryad.9s4mw6mpx)

Life-history data of juvenile Columbian ground squirrels collected in Sheep River Provincial Park in Alberta, Canada.

## Description of the data and file structure

The data is in an Excel file containing all the data used for this article. The different cell captions are described on the second sheet of the Excel file called: tanner final 1a.

A second file called Final_squirrel.R contains the R codes for the statistics and the figure plots.