Evolution is critical to understanding life on Earth. Yet, we still do not fully understand how natural selection operates in the wild because behavior—a critical component of evolution—is exceptionally difficult to measure in the small organisms that evolutionary biologists typically study. I am tackling this on “Lizard Island”: a small island of Caribbean lizards where I directly measure evolution in the wild. By equipping all 1,000 lizards with ultra-lightweight sensors, in combination with a high-resolution 3D map of the ecosystem, I will track organisms continuously as they navigate their habitat and interact with each other. This approach bridges laboratory precision with real-world complexity to reveal evolution’s missing link: the role of behavior. Building upon my decade-long dataset on Lizard Island, my research will create evolution’s first high-definition map, showing precisely where, when, and on whom natural selection acts, redefining how evolution is studied in the wild.