This is the README file (information about) for the data and R code used in the paper **"Shrinking into the big city: Influences of genetic and environmental factors on urban dragon lizard morphology and performance capacity"** published in Urban Ecosystems ([https://doi.org/10.1007/s11252-020-01065-4][1]). Any comments or questions, please contact Dr. Julia Riley: julia.riley87@gmail.com The following are data files (in the *“data”* folder): 1. *gripping_performance.csv* - Data for dragons’ gripping performance on both substrates, and used for comparing if gripping ability differed between substrates 2. *morphology_all.csv* - D ata on the morphological traits of all dragons - adults, hatchlings, and those in the factorial experiment 3. *performance_all.csv* - Data on the tests of performance ability of the yearly dragons To run the analysis and plot Figure 2 in the paper, use the following R script files (in the *"script"* folder): 1. *adult_morphology.R* - Analyses examining differences in morphology between adult female and male dragons from urban and natural populations 2. *hatchling_morphology.R* - Analyses examining differences in morphology between hatchling dragons from urban and natural populations 3. *factorial exp_morphology.R* - Analyses testing for differences in morphology between yearling dragons from urban and natural origin populations, and raised in urban and natural treatments 4. *factorial exp_performance.R* - Testing for differences in performance measures of yearling dragons 5. *figure2.R* - Code for Figure 2 in the manuscript This is a support file that is used in the code (in the *"support"* folder): 1. *summarySE.R* - R code used to summarise raw data easily in our analysis [1]: http://doi.org/10.1007/s11252-020-01065-4