Bailey Howell: Learning from lizards

This photo shows the upper torso and head of a young white woman wearing a black hooded sweatshirt and an illuminated headlamp. She is smiling at the camera. — Researcher Bailey Howell uses a headlamp for nighttime herpetology fieldwork. Photo courtesy of Bailey Howell.

The following story was written in December 2021 by Elizabeth Boyer in ENGL 4824: Science Writing as part of a collaboration between the English department and the Center for Communicating Science.

Bailey Howell loves lizards. Her affection for the reptiles is clear from the way she talks about them, from the silver, lizard-shaped ring she wears around her index finger, and from her research focus: She studies the evolution of traits in lizards, specifically how lizards evolve adaptations for survival in urban environments.

This photo shows the green-t-shirt-clad chest of a person. In the foreground is their hand with a open-mouthed green lizard perched on a finger. The person's face is not visible but some curly light brown hair hangs over one shoulder. — Bailey Howell holding a lizard she has measured. Photo courtesy of Bailey Howell.

Howell grew up chasing lizards around her hometown of Tuscaloosa, Alabama. Although she thought she grew out of her interest in the creatures, her childhood primed her for what was to come. In her college years at Mississippi University for Women, Howell was focused on her biology degree. One day, a professor visited her class in search of an assistant.

“Basically, his pitch was, ‘I’m studying lizards and their sticky feet, and I want a student to help me,’” Howell remembered. Knowing that she could benefit from the research experience, Howell signed up. The research rekindled her interest in lizards, “and I just fell back in love with what I had found my love for as a child,” she stated.

After this research stint ended, Howell studied other things for a while. “But I just missed what I was doing; I missed the lizards,” she said. “I missed studying their [evolutionary] tree, and how they changed in different environments, and the like.”

This photo shows one leg and foot, with toes extended and claws visible, of a scaled animal. In the background are the gridlines of a measuring device such as a meter stick. — A closeup of a lizard foot. Photo courtesy of Bailey Howell.

Now, as a second-year Ph.D. student at Virginia Tech, Howell wants to know how urban environments affect the evolution of lizards.

“I'll try to see how [the lizards and their traits] evolved throughout the past,” Howell explained. “When you try to see how it has evolved, you get a rate of evolution, which is how quickly the trait has changed through time.”

To get this look into the past rate of evolution in lizards, Howell studies charts of lizard evolution, called phylogenies or trees, that have been created by other scientists. The phylogenies she uses show how different types of lizards are related to each other. Instead of showing connections between individuals, like a family tree, they show how different species are related to one another. Sometimes she visits museums to observe and measure the preserved bodies of lizards.

This photo shows a person in a light green t-shirt and purple lab gloves holding a set of calipers or similar measuring tool. — Bailey Howell measuring a lizard for her evolution studies. Photo courtesy of Bailey Howell.

After gathering data about the past evolution of lizards, Howell’s goal with the two groups of lizards she studies is to “see if one group, with regards to a certain trait, has changed more than the other, and if that is going to influence how quickly those traits change out in the wild, between urban and forest sites.” Explaining further, Howell stated that “you can actually go out and measure the traits and then see how they've changed in an urban environment versus a natural [environment].”

This image shows a graph of limb length (y axis) and body size (x axis) for two lizard types, Hemidactylus and Anolis. — Bailey Howell plots limb length against body size for two types of lizard and uses measurements to fit the lizards into models of evolutionary relationships. Image courtesy of Bailey Howell.

Howell aims to do these kinds of hands-on observations later in her research by catching and studying lizards in Florida cities. For now, Howell says that “a very large portion of my time is using computer models. A lot of what I do is fine tuning or comparing models and computer work.” These models use phylogenies to “statistically reconstruct the history of the organism’s traits and to give back a rate [of evolution],” according to Howell.

Despite the electronic nature of much of her work, Howell’s research has very real applications.

“There are species that can survive in an urban environment and that do survive and live in an urban environment very successfully,” she explained, “and those species really interest me because that's not true for a lot of animals.”

Bailey Howell presenting her research at a conference. Photo courtesy of Bailey Howell.

Howell’s work in the evolutionary history of lizards allows her to make predictions about the effect of urbanization on lizard populations. The data she gathers could, in the future, aid scientists in figuring out why some animals, such as squirrels or pigeons, thrive in urban settings, based on how they changed throughout the past.

“To my knowledge, there isn't anyone doing that” for lizards, Howell said, so her studies could pave the way for more research in this area. To anyone who talks to her about the creatures, one thing is clear: Howell’s love for lizards is contagious.