- Researchers analyzed the DNA of spotted skunks and found that instead of the four species previously recognized by science, there are actually seven.
- Spotted skunks are sometimes called the “acrobats of the skunk world” because of their impressive handstands, which warn predators that a noxious spray is coming their way.
- Among the new species, the Plains spotted skunk is in significant decline, with habitat and prey loss during the spread of industrial farming likely being the cause.
- Figuring out the different species lineages could inform conservation efforts, one of the study authors said, “Once something has a species name, it’s easier to conserve and protect.”
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North America’s well-known striped skunk (think of the cartoon Pepé Le Pew) has a lesser-known cousin: the spotted skunk. Smaller, about the size of a fat squirrel, these polka-dotted relatives make impressive handstands to warn predators before launching their foul-smelling spray. And now this skunk group has a few more members.
Researchers analyzed spotted skunk (Spilogal spp.) DNA and found that instead of the four species of skunks previously recognized by science, there are actually seven. Their findings have been published in the journal Molecular phylogenetics and evolution.
Scientists used DNA from 203 specimens of skunks, both modern species and those in museum collections. “If we want to tell the full story of skunk evolution, we need as many samples as possible,” Ferguson says. “For example, we didn’t have modern tissues from Central America or Yucatan. We have been able to use museum collections to fill in those gaps.”
Skunks are notoriously difficult to study in the wild, in part because catching them is an easy way to get sprayed, and also because they are adept tree climbers that live in remote areas. To give the researchers enough specimens to study differences in the DNA of spotted skunks, they used a method common in the days of the Wild West: wanted posters.
“We made posters that we distributed all over Texas in case people would trap them or find them as road deaths,” said Ferguson, who collected copies for this project while working on his master’s degree at Angelo State University. . “People recognize spotted skunks as something special because you don’t see them every day, so they’re not the kind of road deaths people just paint over.”
The paper’s lead author, Molly McDonough, a biology professor at Chicago State University and research associate at the Field Museum, was able to extract DNA from centuries-old museum specimens. “It was really exciting to see who those people were related to. It turns out that one of those species was a currently unrecognized, endemic species to Yucatan,” McDonough said.
Spotted skunks are sometimes called the “acrobats of the skunk world” because of their impressive handstands that warn predators that a noxious spray is on the way. Their liquid deterrent contains sulfur-based organic compounds called thiols that give off a blast of odor reminiscent of rotten eggs — a scent that can linger for days or weeks in the fur of a predator or unlucky pet.
Handstands and rotten-egg-smelling defenses aren’t their only unusual features. Spotted skunks also do something called delayed egg deployment: breed in the fall but don’t give birth until spring. Scientists think some animals do this to delay birth until conditions are more favorable, such as when temperatures are warmer and food is more readily available.
“They delay implanting the egg in the uterus, it just stays in suspension for a while,” Ferguson said. “We want to know why some species have delayed implantation and others have not, and figuring out how these different species of skunk have evolved can help us do that.”
Mapping the different types of lineages can also inform conservation efforts, Ferguson said. “Once something has a generic name, it’s easier to preserve and protect,” he said. “When a subspecies is in trouble, sometimes there’s less emphasis on protecting it because it’s not as clearly an evolutionary lineage as a species.”
Among the new species is the Plains spotted skunk (Spilogal interrupta) is in serious disrepair. The working hypothesis, Ferguson told Mongabay, is that the species suffered a double whammy of habitat and prey loss as industrial agriculture spread to the Great Plains regions of the US where the skunks live.
For example, there were once many spotted skunks in Iowa, living in the spaces between small family farms where their prey (rodents and insects) could be easily found. However, when farms were merged into larger monocultures, these wild “in-between spaces” were swallowed up by rows of corn, soybean and other crops doused in pesticides, leaving little to no healthy habitat or food for wildlife.
Currently, the Plains spotted skunk is being considered for inclusion at the subspecies level as endangered under the U.S. Endangered Species Act. Ferguson said this study adds credence to the argument that this species represents a clear evolutionarily significant lineage and “definitely deserves protection” as a full species.
Ferguson said he also hopes these new findings “will encourage local scientists to get out there and study these species in their own backyard.”
Although North American mammals and carnivores are among the most studied groups of animals, scientists are still discovering and learning new things about them. For example, there is little published literature on the endemic Yucatan spotted skunk (Spilogale yucatanensis), and learning more about simple things like what they eat and how they move can be important for understanding and preserving regional populations.
“The next step, in my opinion, is to see how these seven species differ from each other ecologically,” Ferguson told Mongabay, “because only then can we truly understand what it takes to conserve and protect these truly enigmatic little carnivores. “
McDonough, MM, Ferguson, AW, Dowler, RC, Gompper, ME, & Maldonado, JE (2021). Phylogenomic systematics of the spotted skunks (Carnivora, Mephitidae, Spilogal): Additional species diversity and Pleistocene climate change as a key driver of diversification. Molecular phylogenetics and evolution, 107266. doi:10.1016/j.ympev.2021.107266
banner image Western spotted skunk (Spilogale gracilis). Image by Robby Heischman courtesy of the Field Museum..
Liz Kimbrough is a staff writer for Mongabay. Find her on Twitter: @lizkimrough_
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