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Lydia Slattery
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Phone: 563-387-1417

Luther College professor Dawn Reding is trying to understand why the gray fox population is declining across the Midwest

DECORAH, IOWA—The gray fox population is declining across the Midwest; Dawn Reding, associate professor of biology at Luther College, is trying to understand why. She’s leading part of the lab work of a multi-state study, which includes Iowa, Indiana and Illinois, on gray foxes. 

While many gray foxes are dying of canine distemper, a highly contagious virus that attacks the respiratory, gastrointestinal and nervous systems of canines, that doesn’t tell the whole story. The disease has affected gray foxes since at least the 1970s, but the population decline has significantly increased in recent years. 

Dawn Reding

“There are multiple factors involved in the decline of gray foxes,” Reding said. “We are still putting together all the pieces; it’s going to be a complex story.” 

Reding has been studying the decline for the past four years through a grant with the Indiana Department of Natural Resources and the Wildlife Ecology Institute (WEI), a nonprofit that researches and manages wildlife. Reding’s part of the study focused on genetic testing to understand how gray fox movement patterns, diet and prevalence of bacteria in their gut could contribute to disease susceptibility.

The researchers are also working with Kansas State and Purdue University. Reding’s team collected blood and tissue samples and sent them to a team at Kansas State to test for various viruses and parasites at its diagnostic lab, then researchers at Purdue and Reding’s team examined carcasses to determine the cause of death of gray foxes.

She hopes to begin a new four-year study with the Indiana DNR and the WEI on possible comorbidities that could be exacerbating the spread of canine distemper among gray foxes by testing DNA. 

Reding and her team are looking into habitat as a possible reason for the decline, since gray foxes are coming into closer contact with humans as their natural habitats shrink due to development. The animals may come into contact with common household toxins like rat poison or antifreeze. Lab tests revealed that a gray fox had died after ingesting antifreeze. 

Gray fox on a white blanket.

A gray fox that was captured during the study before being released. Photo credit: Julia Nawrocki

There’s also a possibility that gray foxes could be in competition with other species such as coyotes and bobcats. This could mean they don’t have access to nutritious food to keep their immune systems strong and fight off canine distemper. 

Luther students worked under Reding,which gave them valuable skills for their future professions. 

Poppy Thuy Duong Truong, a junior majoring in identity studies, helped examine the animals last summer as a research assistant for the study. She traveled to Indiana, where many gray foxes are found, to collect the bodies and study them.

Young woman in a white lab coat looking at samples in a lab.

Poppy Thuy Duong Truong works in the lab as part of the gray fox study.

“During the research project, I learned how to work collaboratively and learned how to communicate with my team members,” Truong said. “These are skills that I can take into a future career.” 

A Luther student also helped analyze the DNA of gray foxes to understand the species better. Adam Koller, a senior majoring in data science and mathematics who also worked as a research assistant, helped Reding in interpreting DNA sequencing data during the study last summer. 

“I was working with the sequence data after it was sent to a lab for testing to understand gray foxes,” Koller said. “While it’s a biology research project, I found a way to fit it into the study with my data science experience.” 

Gray foxes are not officially considered endangered, but have become a species of concern. It is legal to hunt the animals, but gray foxes are not a typical game. According to the Iowa DNR’s “Trends in Iowa Wildlife Population and Harvesting” logbook, only one gray fox was harvested during the 2021-22 hunting season. It was hunters and trappers in the Midwest who acted as the catalyst for the study when they noticed the decline and alerted wildlife officials. 

They are North America’s only canine species that can climb trees because of their long, hooked claws. This allows them to escape predators or find food sources in trees. Rodents are also a part of the foxes’ diet, giving the foxes an important role in regulating rodent populations. 

“There is not a lot known about gray foxes since they’re not well-studied,” Reding said. “This study is very broad and comprehensive to understand the species better.” 

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Contact Information

Lydia Slattery
Media Relations Specialist

Phone: 563-387-1417