There was nothing particularly unusual about Bridgette vonHoldt receiving an email from a man in Texas with pictures of strange-looking, reddish-hued coyotes.
As an associated faculty member in the Department of Ecology and Evolutionary Biology (EEB) and at the Lewis-Sigler Institute for Integrative Genomics, vonHoldt specializes in the hybridization of canids, a family of mammals that includes dogs, wolves, and coyotes. As a result, she gets a lot of queries from dog owners in her inbox asking her to identify the ancestry or possible wolf heritage of their furry best friends.
But something about the canids in these particular photos, taken on the Texas Gulf Coast island of Galveston and sent to vonHoldt by a man named Ron Wooten, caught her attention. They looked like red wolves, a species native to the southeastern United States.
The strange part? Red wolves have been extinct in southeastern Texas for four decades.
Intrigued, vonHoldt followed up with Wooten. According to The New York Times, Wooten, a Galveston resident, had become fascinated by the canids, which he suspected might have some red wolf ancestry, after they killed his own dog. He had previously collected two tissue samples from roadkill; having lost one of the samples, he sent vonHoldt the first as well as the scalpel he had used for the second. It was enough for vonHoldt and her team at Princeton to extract DNA and sequence the genomes, and thus determine the genetic makeup of these animals.
On that team was Elizabeth Heppenheimer, an EEB graduate student at the time who now works as a science writer at the Broad Institute. She remembers her own surprise at the results of the genome sequencing.
“I ran a few initial analyses and then ‘Wait a second,’” she said. “I thought I had done something wrong.”
The results of the sequencing showed that the samples from the two Galveston coyotes contained 20–30 percent red wolf ancestry.
“The red wolf went extinct in the wild by 1980,” vonHoldt remarked. “So why or how can something have red wolf genetics if it hasn’t been around a red wolf for 40 years?”
Red wolves used to roam freely throughout the southeastern United States, until habitat loss and predator control programs drove them to near extinction in the twentieth century. By the early 1970s, they could only be found in southeastern Texas and Louisiana; then, even that waning population disappeared. The coyote, known for its adaptability to human-altered environments, took over as the dominant canid in the region.
Today, fewer than 20 red wolves constitute the only members of the species not in captivity. These wolves are living in North Carolina as the result of a conservation effort in the 70’s. The era of the wild red wolf roaming the Gulf Coast was considered by experts to be over.
That had been the extent of the story, until vonHoldt’s team looked closer at the genomes of the strange-looking Galveston coyotes. Though the red wolf vanished from coastal Texas and Louisiana four decades ago, the results of their research showed that the species’ genetic legacy lives on through the region’s canids.
Now a new story of cross-species lineage has emerged. As their population numbers dwindled, it appears that red wolves mated with the coyotes who were replacing them. VonHoldt noted red wolf genes found in coyotes today could be the result of mating between the species anywhere from 10 to 100 years ago.
“Even though the red wolf went extinct in the wild, it left behind first generation hybrid offspring, who had pups of their own,” she explained. “Those offspring probably mated with other coyotes, and each other, and those offspring did the same, so that, even in the eventual absence of the red wolf, those genes are still being passed around to each other.”
VonHoldt also thinks coyotes deserve more research attention in general.
“People see coyotes all the time, but no one thinks to study them. They mostly just want to kill them,” vonHoldt said. “But they’re more than just pests: they’re a fascinating species who are incredibly adaptable. They live in every nook and cranny, in every habitat from backyards to cornfields.”
After all, as Tanner Barnes, a graduate student at Michigan Tech involved in the study, noted, “once the red wolves went extinct, the coyotes took over the entire eastern half of North America. They’ve been able to adapt to human interference with habitat.”
After the initial findings of vonHoldt’s team, researchers have continued to study the hybrid coyotes, analyzing more samples and widening their focus to outside Galveston Island.
For instance, Barnes went to Galveston multiple times to systematically collect more DNA samples.
“We collected fecal samples, tissue with the help of Animal Control, samples from roadkill,” he said. Some of the samples he collected from the mainland displayed nearly 50 percent red wolf ancestry.
“We’re trying to learn everything we can,” vonHoldt said. “We’ve looked at canids from a wider geographic range, but found that this was very isolated. It’s a hot spot in eastern Texas that floods into Louisiana, that’s it.”
Continued research is now aided by the establishment of the Gulf Coast Canine Project, a collaboration between vonHoldt and researchers at Michigan Tech as well as other institutions to support the wild canine population in the region.
The project is motivated by more than just curiosity. VonHoldt pointed out two ways that this research could prove critical to the conservation of the remaining members of the red wolf species in North Carolina, who suffer from a lack of genetic diversity.
“We could try to breed genetic diversity back into the species,” she said, by bringing a Galveston or Louisiana coyote into a captive breeding program with red wolves, though she noted the ethical concerns of cross-species breeding. “There’s also been discussion on bio-banking sperm or stem cells from coyotes that have red wolf ancestry. Is there a way for us to edit genes, to cut out some red wolf genes and put them into a surrogate to eventually get a reconstructed red wolf?”
The answer to that remains uncertain. What is clear, according to vonHoldt, is that the red wolf is “not doing well and very close to a possible extinction.”
“Biotechnology might be used to help rescue a highly endangered species,” she said. “Which could be amazing.”
Paige Cromley is an assistant Features editor and a writer for the News and Prospect sections of the Daily Princetonian. She can be reached at email@example.com.