Happiness is discovering there are a lot more species of hand-standing spotted skunks than we thought. Almost double the number, in fact.
Yes, there had been more disagreement over how many species of spotted skunks than one would think. “Over the years, the number of recognized species has ranged from two to 14, and lately, scientists have agreed there are four,” the scientists at the Field Museum of Natural History in Chicago explains. Yet this was not so: There are seven, claim researchers in a new paper in Molecular Phylogenetics and Evolution following genetic analysis of said spotted skunks.
To be clear, the striped skunk of cartoon fame is something else altogether, though the academics note that in spotted skunks, the spots are actually “broken stripes.”
Among other things, spotted hand-standing skunks are smaller than their striped relatives. And when alarmed or peeved, they stand on their heads. Meaning, they balance their furry bodies on their forepaws, their rear paws in the air and their lusciously fuzzy tail waving in the breeze, and then if stressed, aim their tush and spray. Striped skunks are not known to do handstands.
Before we address their scientific classification, why do they do that? The assumption is that it’s like why cats puff up – less to amuse us and more to intimidate enemies by making them seem bulkier than they are, according to Business Insider. The website also begs to stress that they will spray you as happily as the familiar striped skunk: “If you happen to run into one of these smelly, spotty animals, keep your distance,” it advises.
Here is a BBC video of a spotted skunk standing on its head. Enjoy.
How did science get the spotted skunk so wrong, so far? For one thing although the spotted skunk throngs North America, it’s wild and shy, not to mention small. Most weigh less than two pounds, the team explains, and they avoid urban areas. Striped skunks can weigh more than 10 pounds and will raid your garbage.
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Also, people may sidestep skunk speciation as a professional focus because catching these animals is a good way to get sprayed, the team helpfully observes.
In practice skunks are omnivores: If you leave it, they will eat it. But technically they belong to the Carnivora, not the rodent set. They are distant cousins of dogs, and even more distant relatives of cats. They are very close cousins of badgers and weasels. In short, they’re a wily lot.
A very small skunk
Evolutionary ecologist Adam Ferguson, from Chicago’s Field Museum, was a driving spirit behind this new study. “North America is one of the most-studied continents in terms of mammals, and carnivores are one of the most-studied groups,” he says. “Everyone thinks we know everything about mammalian carnivore systematics, so being able to redraw the skunk family tree is very exciting.”
Anyway, since their first formal recognition in 1758, spotted skunks have confused zoological circles. As many as 14 species had been recognized, the team says, and then in recent years that number was condensed to four.
Ferguson explains that he wondered if that reduction to four species was accurate, given that the spotted skunks get about a vast range, including some geographically isolated areas, and because they had not been properly characterized genetically. Moreover, they happily climb trees. This is a situation begging for a shortfall of speciation estimates.
So, how is one to acquire specimens of an elusive wild animal that can turn you into a social pariah? Not wanting to ascend to the North American canopy or get sprayed, the team resorted to “wanted posters” – not only for trapped animals but for roadkill as well. The posters were hung up throughout Texas because that’s where Ferguson was pursuing his grad studies, team member Kate Golembiewski explains in an interview. However, naturally, there are specimens from other states as well.
“People recognize spotted skunks as something special, because you don’t see them every day, so they’re not the kind of roadkill that people just paint over,” Ferguson observes.
Not relying solely on live or squashed specimens, the researchers also checked stuffed skunks in museum collections.
“If we’re trying to tell the full story of skunk evolution, we need as many samples as we can get,” he continues. “For example, we didn’t have any modern tissues from Central America or the Yucatan. We were able to use museum collections to fill those holes.”
The team’s estimate of seven skunk species is based on the genetic analysis of 203 spotted skunks in various conditions. Using advanced techniques perfected for other tasks, the researchers extracted DNA from deceased skunks up to a century old.
One of the newly “discovered” handstanding skunks is a peewee the size of a squirrel from the Yucatan peninsula – and it is now known as “the Yucatan spotted skunk.” We welcome thee.
Another is the Plains spotted skunk which, just identified as a species rather than a subspecies, is already endangered, the scientists say. Now that they realize the Plains spotted skunk are a distinct evolutionary lineage, it begs the thought that they have been evolving independently of the other skunks for a long time, Ferguson notes.
One wonders how the Plains spotted skunk diverged from the others: Anyplace called “plains” doesn’t lead to an immediate association with geographical isolation. Golembiewski suggests the speciation was driven by climate change during the Ice Age, when glaciers and other horrors of the cold did isolate populations, enabling them to branch off into new variants or species.
“Even though those barriers are now gone, the genetic changes they underwent and the speciation that resulted are relics of that previous isolation,” she suggests.
That isn’t as unusual, in the sense that if we notice a new species larger than a bacterium in our overcrowded world, it will probably be in a remote area and rare. There are exceptions, though – for instance, the unknown frog noticed in New York and New Jersey in 2014 after a scientist heard it croaking and thought, wait a minute, that didn’t sound familiar.
The revised skunk family tree could also be a tool for scientists looking to understand the animal’s reproductive biology, the scientists say. “Besides the fact that they do handstands, the coolest thing about spotted skunks is that some of them practice delayed egg implantation – they breed in the fall, but they don’t give birth until the spring. They delay implanting the egg in the uterus, it just sits in suspension for a while,” says Ferguson.
Yes, that is cool, although they are far from the only species that delay impregnation by this or that mechanism, including sperm storage. But not all skunks perform this minor miracle.
Which leads us to our final question of the team. If the understanding of skunk speciation and variability has seesawed so violently, who’s to say there are only seven and not more, lurking in remote corners and canopies of North America? Maybe the original guesstimate of 14 is still closer to the mark?
Goliembiewski doesn’t think so. “Even remote areas of North America are pretty well studied compared to much of the world, and skunks are relatively big, noticeable animals,” she says – even the spotted variety, which kind of stands out.
“Even though this study’s genetic analysis revealed that some of the skunks we’ve long been aware of are a different species than originally thought, it might be a stretch to say there are a lot more spotted skunk species out there than seven,” she adds.
We shall see. As we said, they’re a wily lot, skunks, being members of the Carnivora, which tend to be smarter than members of their lunch. So there’s that. They’re also close to badgers and at least some of those are believed to be very smart indeed, and good at problem-solving, like the problem of being trapped in an enclosure, or the problem of your garbage can being closed.