- Researchers described the new species in a study published in the Journal of Mammalogy in May. Glaucomys oregonensis, or Humboldt’s flying squirrel, can be found all along the Pacific Coast, from southern British Columbia all the way down to the mountains of southern California.
- It is what’s known as a “cryptic species,” because coastal populations of the squirrel had previously been classified as northern flying squirrels (G. sabrinus) due to their similar appearance.
- A genetic analysis revealed the coastal populations belong to a distinct species all their own.
There are now three species of flying squirrel in North America, and it turns out that the newest member of the family has actually been gliding amongst the treetops of the U.S. West Coast, sometimes right alongside its closest relatives, this whole time.
Researchers described the new species in a study published in the Journal of Mammalogy in May. Glaucomys oregonensis, or Humboldt’s flying squirrel, can be found all along the Pacific Coast, from southern British Columbia all the way down to the mountains of southern California. It is what’s known as a “cryptic species,” because coastal populations of the squirrel had previously been classified as northern flying squirrels (G. sabrinus) due to their similar appearance. A genetic analysis revealed the coastal populations belong to a distinct species all their own.
“For 200 years we thought we had only had one species of flying squirrel in the Northwest — until we looked at the nuclear genome, in addition to mitochondrial DNA, for the first time,” Jim Kenagy, professor emeritus of biology at the University of Washington (UW) and a study co-author, said in a statement.
Kenagy is also curator emeritus of mammals at UW’s Burke Museum of Natural History and Culture. It was the Burke Museum’s collection of specimens that led the study’s lead author, Brian Arbogast, to take a closer look at the flying squirrel genetics. Arbogast is an associate professor of biology at the University of North Carolina Wilmington, but was a postdoctoral researcher at UW and the Burke Museum when he first began to suspect that there may be an as-yet unrecognized species of flying squirrel.
The Burke Museum’s specimens have been collected since the early 1900s, and Arbogast noticed that, while similar in appearance, the squirrels from the Pacific Coast region were often smaller and darker than populations found east of the Cascades.
“I’ve been scratching my head over these squirrels since 1992,” Arbogast told National Geographic. “There was just something weird about those from the West Coast.”
Arbogast and team’s DNA analysis ultimately revealed not only that coastal populations of the flying squirrels, from southern British Columbia down through western Washington and Oregon and into California, are members of a distinct species, but also that there is no genetic exchange occurring between those coastal populations of what is now called Humboldt’s flying squirrel and inland populations of the northern flying squirrel even though the two species are known to occur together in some parts of western Washington state and southern British Columbia.
Arbogast and team write in the study that “mtDNA data from 185 individuals across North America revealed 2 distinct clades embedded within G. sabrinus: a widespread ‘Continental’ lineage and a more geographically restricted ‘Pacific Coastal’ lineage.”
“It was a surprising discovery,” Kenagy said. He and Arbogast are amongst a group of researchers who study small mammal distribution in the western and eastern mountain ranges of the U.S. Northwest. “We were interested in the genetic structure of small mammals throughout the Pacific Northwest, and the fact that in other cases we were aware that two different species had evolved in Eastern and Western Washington.”
Humboldt’s flying squirrel becomes the 45th known species of flying squirrel in the world. All three species in North America (including the newly discovered G. oregonensis, G. sabrinus, and the southern flying squirrel, G. volans) are small, nocturnal woodland creatures. They don’t actually fly, of course, but glide between trees, for up to 100 meters, on furred membranes of skin that stretch between their forearms and hind legs. Their gliding ability is remarkable, however, as flying squirrels are capable of making sharp turns in midair by using their tail as a rudder and changing the shape and tautness of their gliding membranes with their limbs.
The new species was named in honor of naturalist Alexander von Humboldt.
- Arbogast, B. S., Schumacher, K. I., Kerhoulas, N. J., Bidlack, A. L., Cook, J. A., & Kenagy, G. J. (2017). Genetic data reveal a cryptic species of New World flying squirrel: Glaucomys oregonensis. Journal of Mammalogy. doi:10.1093/jmammal/gyx055
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