The overall goal of this project is to understand why individual animals behave differently from one another using three-spined stickleback fish as a model organism. To that end, this project measures the behavior of individual sticklebacks in behavioral essays in both field and laboratory settings and collect biological materials samples for genetic, molecular, neural, and hormonal analyses. They also use the ultra-low freezer for long term storage of critical biological materials for future studies. For example, we have been tracking individual differences in behavior within certain stickleback populations over the last 20+ years and long term, reliable storage of those samples facilitates the analysis of long-term changes in the population.