Hammerhead Shark Research Pushes Senior to Think Outside the Tank

Haley Amplo ’17 loves rock climbing, especially in the Southeast. She likes the way the rock formations have created climbing routes that keep her intrigued.

“I love climbing. It’s a game. It’s a challenge, a puzzle to figure out,” said Amplo, vice president of UT’s rock climbing club, a University club sport. “Even when you’re in the gym, and they’ve got marked off holds, it’s still ‘how can I figure it out in a way that’s different than how everybody else is figuring it out,’ which I think relates a lot to science.”

She should know. Amplo has been problem solving her way through the hammerhead shark research she’s been conducting these past two years with Daniel Huber, associate professor of biology. They are studying why the shape of hammerhead sharks’ heads have evolved as they have.

“Hammerheads are really strange,” said Amplo, a marine science-biology major with a minor in chemistry. “They have a wing strapped to their face. Why would they have that?”

Huber explains that hammerhead sharks are characterized by an extremely unusual head shape called the cephalofoil, or head wing. Past studies have focused on the sharks’ sensory systems and how the head shape might be advantageous in terms of the range of vision, turning radius and ability to pick up different electrical impulses as compared to other closely related sharks. But the issue of the shark’s fluid dynamics and how they impact its evolution has been ignored.

“In this study, six hammerhead species were examined to determine if cephalofoil shape affected fluid drag during locomotion. Head models were 3-D printed from reconstructed CT scans and fluid drag measurements were performed at varying angles of attack in a recirculating flume, from which drag coefficients were derived,” Huber said. “It was hypothesized that cephalofoil size and shape will influence fluid drag, and ultimately swimming performance.”

Amplo, who is participating in this research independently, was attracted by the topic and by the professor.

“When I first met with Dr. Huber I kind of fan-girled a little bit because he was on Shark Week,” she said laughing. (Huber and his colleagues are the first to have successfully measured voluntary bite force in free-swimming sharks, and he has been featured several times on Discovery’s Shark Week.) But it’s been a lot of work — in research on her own and then most Fridays in the waterfront Marine Science Field Station.

“Haley has a tremendous work ethic and the intellect to understand connections between different fields of science,” Huber said. “This project uses engineering principles (fluid dynamics) to understand the evolution of one of the oddest structures in all of biodiversity, the hammerhead cephalofoil.”

Amplo has spent hours working with computer programs that read the CT scans of frozen sharks (collected from a colleague of Huber’s), cleaning up the scans in one model and using another to layer on the shark’s skeletal structure, the muscles and the skin. From there they had the data to 3-D print a shark head using the high caliber 3-D printers through Huber’s connection at USF Health’s Department of Radiology. The heads were then set up in a flume where the team (Huber, Amplo, Taylor Cunningham ’18 and Sara Casareto ’20) was able to take measurements of how the fluid moved around the heads at different angles.

“We’re thinking hammerhead sharks, with this huge cephalofoil, also swimming at a higher angle of attack than most sharks are doing, potentially creating such a huge decrease in force or such a huge increase in lift, that that might be why cephalofoil evolved in the first place,” Amplo said. “Maybe all these sensory benefits are all secondary.”

Amplo said one of her biggest takeaways from this research project is learning how to be creative with fixes, as well as adaptable.

“One of the big things I’ve learned from this project is that science is not this straight line. It’s a lot of troubleshooting,” she said. “I had to learn how to think like a scientist, where there’s not a lab manual in front of you telling you the steps to go by. A lot of it is problem solving on your own. Coming up with an idea when you’re in the shower and writing it down really quick because hey, that might be a good angle to come at it. You have to think outside the box and slightly different than everyone else is thinking.”

The hammerhead shark project will continue next semester with Cunningham taking the lead. For Amplo, of Jamesburg, NJ, coming to UT was a good choice.

“I’d pick UT again solely based on how awesome my professors have been. I do have the ability to go into their offices and they know my name, they know my face, they know about my work ethic — what I’m good at, what I’m not good at, even if I’ve only taken one class with them.”

Amplo presented her research at the Florida Undergraduate Research Conference back in February, along with several other UT students, and she’ll be presenting at the upcoming CNHS Undergraduate Research Symposium April 28, which is part of UT’s Undergraduate Research Celebration Week. Later this summer she hopes to submit her work for publication.

“An experience like this is paramount in helping students decide if they want to pursue research as a career. Accumulating knowledge in the classroom only gets you so far in this regard,” Huber said. “Students need to experience the creative process of developing ideas and collecting/analyzing/interpreting data to know if research is right for them. It also helps students to develop the analytical skills needed to critically evaluate information and make evidence-based decisions, which is crucial to our competence as a society in this day and age.”

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