Raul Diaz: The reptile hunter

Although Raul Diaz hasn’t even defended his thesis yet, his resume already reads like the resume of an accomplished faculty member. No wonder the enterprising rainforest ecologist-turned molecular biologist was offered an assistant professor position straight out of graduate school.

For Raul Diaz, defying expectations is second nature. He grew up in Baldwin Park, California in the eastern Los Angeles area where parents have many a reason to worry about their children’s safety. “My mom didn’t want me on the street and I spent a lot of time in the local library,” remembers Diaz. Before long, he had read every reptile and amphibian book in the library and spent hours hunting for alligator lizards hurrying over sunbaked pavement near his house. By sixth grade he was breeding several species of tree frogs—much to his mother’s dismay—and working with local pet stores to start writing guides on how to breed frogs in captivity.

As soon as Diaz enrolled at La Sierra University in Riverside, California, he extended his reptile hunting forays from Southern California’s urban concrete jungles to the rain forests of Southeast Asia and islands in the Caribbean. “On these trips I came across many animals that had developed similar adaptions to their environments although they were not related and lived in completely different corners of the world,” recalls Diaz. “I became interested in how these organisms develop similar traits, a process that’s known as convergent evolution.”

Diaz transferred to the University of California, Berkeley, to continue his studies. By the time he graduated with a bachelor’s degree in integrative biology, he had half a dozen scientific publications to his name. He had also described several new species, made significant contributions to the Peterson Field Guides: Western Reptiles and Amphibians, traveled to Africa, founded a herpetology club at UC Berkeley and revived a peer-reviewed journal, Asiatic (now Asian) Herpetological Research, which he would continue to publish out of his apartment for almost a decade. The journal is now the main outlet for papers on reptile and amphibian biology from Asia to Australia.


Raul Diaz

Driven by a lifelong attraction to frogs—as his friends and tattoos on his right forearm can attest—Diaz started a PhD thesis on frog skeletal development and evolution at the University of Kansas Natural History Museum in Lawrence. He quickly became frustrated with the strict partitioning of departments into traditional disciplines such as ecology, development, morphology and molecular biology. “I realized that the field was headed towards combining molecular biology with morphological studies but, at the time, KU Lawrence didn’t offer any interdisciplinary training in vertebrates.” He finished up his frog project as part of a master’s thesis and started working with former Stowers Investigator Olivier Pourquié, PhD, who studied snake segmentation. “I had been looking all over the country to find a lab where I could do interdisciplinary work and there it was, right in front of my nose,” recalls Diaz.


When Pourquié left to take a position in France, Diaz stayed on to take advantage of the Stowers Reptile and Aquatics facility. Undeterred by yet another change in plans, he joined the lab of Stowers Investigator Paul Trainor, PhD, an expert in craniofacial development, and dusted off an old interest he had developed during a summer internship at the Smithsonian Institution. “I had studied the crests of basilisk lizards,” he explains. “On the outside they look similar to chameleons’ crests but they are structurally different on the inside.”


Raul Diaz on a reptile hunting trip in the Shai Hills Resource Reserve in Ghana, Africa

Drawing on Trainor’s expertise in craniofacial development, Diaz was able to look at crest development with molecular tools. “Compared to other lizards, the chameleon has a substantially modified body plan,” he says. “Molecular signals are ‘recycled’ across different body parts, which is the key to understanding these developmental modifications and ultimately how reptile body forms change during evolution.”


In his own lab at La Sierra University, with an adjunct position at Loma Linda University Medical Center, Diaz will continue his research program on skull morphology and the biology of reptiles and amphibians of mainland and Southeast Asia. In addition, he plans to study reptile hands. All chameleons have a split in their hand that helps them climb the plants they inhabit. “Certain human birth defects look very similar to chameleons’ split hand and foot,” he explains. “Most of these cases can be explained by genetic mutations but lab studies have hinted at environmental causes as well. Perhaps the chameleon can provide some unique insight into these extreme structural defects.”

But Diaz is most excited about the opportunity to teach the very same course at La Sierra University that allowed him to explore rain forests all over the globe, while also teaching development and genetics. He hopes that “expanding the lab to the jungles will hopefully produce students as excited about science as I am!”