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Hendrix Students Study Aquatic Mammals

Dr. Jenn Dearolf leads seal and dolphin studies for Skeletal Muscle Biology Lab

CONWAY, Ark. (August 9, 2024) — Central Arkansas may not seem like a place where one could study aquatic mammals, but Hendrix College Professor of Biology Dr. Jenn Dearolf’s Skeletal Muscle Biology Lab has been making it happen for years now.

Starting in 2017 with students Lindsey Barrett ’19, Elijah Ballard ’19, McKenzie Fletcher ’20, Veneeza Mukhtar ’21, Sundus Nazar ’21, Hannah Fewell ’24, and Kelsey Sample ’25, Dearolf and her team began investigating the locomotor muscles of different species of seals found in the Arctic to better understand their abilities to swim and dive. These seals rely on sea ice, which is disappearing in the rapidly warming Arctic, as a resting and diving platform, so knowledge about these abilities is crucial.

In more than 25 years of studying marine mammals, Dearolf had never had the opportunity to study the muscles of a seal, and this project allowed her and her students to look at three species. 

“And not just any seals — Arctic seals!” she said. “These animals are challenging to study because of the difficulty in accessing their habitat, but through our collaborators, we were able to collect data revealing the fiber composition of their locomotor muscles. These data can now be used by others to begin to assess how well the seals will adapt to the loss of sea ice.”

Dearolf and her students worked with Anna Bryan at the Alaska Department of Fish and Game, Dr. Colleen Reichmuth at UC Santa Cruz, and Mariah Tengler, a graduate student in the lab of Dr. Nicole Thometz at the University of San Francisco. The work of Dearolf’s students and Tengler was recently published in the journal Aquatic Mammals, the oldest peer-reviewed journal publishing papers on marine mammal science. 

More recent work in Dearolf’s lab has moved to mammals living in warmer waters. Since the summer of 2021, Ian Campbell ’23, Savanna Watts ’24, Hannah Fewell ’24, Kelsey Sample ’25, and Emma Self ’25 have been studying the development of locomotor muscles in spinner dolphins, which are found in the waters off the islands of Hawaii. These students are comparing the properties of the muscles of calves, juveniles, and adults to determine if spinner dolphin calves are able to keep up with their mothers and the rest of the pod when they are chased by tuna fishermen. 

Like the Arctic seal work, the spinner dolphin study is a collaboration with Dr. Shawn Noren at UC Santa Cruz. The data collected by Dearolf’s students are being incorporated into a manuscript and will serve as preliminary data for a National Science Foundation (NSF) grant being submitted by Noren and Dearolf.

Both studies have been supported by Odyssey grants to Dearolf and her students. 

“Through working on these projects, my students gain valuable skills, including critical thinking and problem solving,” Dearolf said. “In addition, each of them presented the results of their studies at scientific conferences and thereby improved their oral communication skills. They also got to interact with other scientists and hear about their research — all things the Odyssey Program encourages and makes possible through the funding it provides.”

Dearolf added that many of the student researchers who contributed to this project have since gone on to medical, veterinary, or pharmacy school, while others have begun careers in healthcare or research.

“These recent graduates and I shared some really wonderful learning experiences during their time at Hendrix,” Dearolf said. “I love seeing how their paths are unfolding.” 

More information about the Odyssey Program is available at hendrix.edu/odyssey.

Visit Dearolf’s Skeletal Muscle Biology Lab website at www.smubl.com

For more about the Arctic seal study, read the research at the Aquatic Mammals Journal website

About Hendrix College

Founded in 1876, Hendrix College is featured in Colleges That Change Lives: 40 Schools That Will Change the Way You Think About Colleges and celebrated among the country’s leading liberal arts colleges for academic quality, engaged learning opportunities and career preparation, vibrant campus life, and value. The Hendrix College Warriors compete in 21 NCAA Division III sports. Hendrix has been affiliated with the United Methodist Church since 1884. Learn more at www.hendrix.edu. 

“… Through engagement that links the classroom with the world, and a commitment to diversity, inclusion, justice, and sustainable living, the Hendrix community inspires students to lead lives of accomplishment, integrity, service, and joy.” —Hendrix College Statement of Purpose