James Stroud has been named a 2025 Packard Fellow for his pioneering research in evolutionary biology. Stroud, Elizabeth Smithgall-Watts Early Career Assistant Professor in the School of Biological Sciences, will receive $875,000 over five years to fund his work on “Lizard Island” in South Florida. His goal? To create evolution’s first high-definition map — with the help of 1,000 backpack-wearing lizards.

Awarded annually to just 20 individuals by the David and Lucile Packard Foundation, Packard Fellowships for Science and Engineering support researchers pursuing cutting-edge research and ambitious goals. “These visionary Packard Fellows are pushing the boundaries of knowledge, and their bold ideas will become tomorrow’s real-world solutions,” says Nancy Lindborg, president and CEO of the Packard Foundation in a recent press release.

The flexible funding allows researchers to maximize their creativity and ingenuity. Stroud will spend the next five years transforming Lizard Island into the world’s premier evolutionary observatory, merging groundbreaking technology with long-term field research.

On Lizard Island, that means equipping every lizard with an ultra-lightweight sensor “backpack.” Although the sensors weigh just six-hundredths of a gram each — the same as two grains of rice — when combined with innovations in mapping technology, they will help Stroud investigate the role that behavior plays in driving evolution in the wild.

“I’m incredibly honored to be named a 2025 Packard Fellow,” says Stroud. “This support allows me to pursue a question that has fascinated evolutionary biologists for centuries: how does behavior shape evolution? It’s a transformative opportunity, and I’m deeply grateful to the Packard Foundation for believing in the potential of this work.”

Tiny sensors, big questions

Begun in 2015, Stroud’s work on Lizard Island is one of the longest-running evolutionary studies of its kind: for the last 10 years, he has carefully caught and released every lizard on the island, measuring evolution through documenting their body characteristics, habitat use, and survival.

Through his studies, he has captured evolution in action, but monitoring and measuring behavior in evolutionary studies has historically been an extremely difficult and elusive task. The problem? While smaller animals tend to have higher population densities and reproduce more quickly (making them ideal candidates for evolutionary field studies), it has been difficult to find durable and long-lasting sensors small enough for these animals to carry.

“This has been a missing link because behavior is a critical component of evolution,” Stroud says. “Behavior can both expose individuals to — or shield them from — natural selection. For example, an animal with a less favorable trait, like bad eyesight, could change its behavior to avoid situations where it is disadvantaged. 

“These decisions can ultimately determine whether they survive and reproduce in the wild, directly influencing the outcome of natural selection. However, until now, we just haven’t had the technology to measure these types of extremely intricate behaviors across many individuals before.”

Mapping the future

Stroud won’t just know exactly where each lizard is — he’ll also create a detailed three-dimensional map of the entire island using remote sensing technology called LiDAR, updating it each year. “By shooting millions of laser beams, we can create a highly detailed three-dimensional map of Lizard Island, capturing the shape of every branch, rock, and blade of grass on the island,” he explains. “When connected to our lizard backpacks, we’ll know the exact microhabitats and resources available to each lizard as they move through this environment.”

Stroud will also deploy hundreds of microclimate sensors to understand how species are reacting to changes in temperature and climate. The result will be the world’s first comprehensive database: a record of minute lizard movements, the resources each individual uses, daily interactions, and changes in the environment spanning seasons and years. 

“For evolutionary scientists, it has been seemingly impossible to track the moment-by-moment decisions of individual organisms… until now,” he says.

“Today, it’s possible to study what Darwin could only dream of — evolution occurring in real time,” Stroud adds. “Behavior is a critical component of evolution, understanding evolution is critical to understanding life on Earth, and understanding life on Earth is more important than ever.”