Tag Archives: skunk

The family of hand-standing skunks just got bigger

If you see a skunk doing a handstand, as remarkable as the sight may be, you should probably step back. A few good steps back. It’s the last warning before they start spraying with their famous putrid-smelling liquid.

Not all skunks do handstands, just the spotted ones. The most common skunk in North America is the striped skunk — a stocky animal, around the size of a housecat, black with white stripes; think Pepé Le Pew. The spotted, hand-standing skunk is smaller, at under one kg (two pounds), and a bit more mysterious than its striped cousin.

Researchers even debated how many species of spotted skunk there are, with the number ranging from two to fourteen, and later settling in on four. But according to a new study on skunk DNA, there are actually seven species.

A spotted skunk doing its signature handstand. Image credits: Jerry W. Dragoo.

The acrobats of the skunk world

The Wikipedia page of the spotted skunk (and pretty much all the sources you can find) lists four extant species of spotted skunk: S. gracilis, S. putorius, S. pygmaea, and S. angustifrons — with the “S.” standing for the Spilogale genus of the spotted skunk.

But a team of researchers has a different idea on these species, and they have the DNA to back it up.

“I was able to extract DNA from century-old museum samples and it was really exciting to see who those individuals were related to. It turns out that one of those was a currently unrecognized, endemic species in the Yucatan,” says Molly McDonough, a biology professor at Chicago State University, research associate at the Field Museum, and the paper’s first author.

It’s striking that even for such a well-known animal as the skunk, on a relatively well-explored continent, we can still find out new things, and re-align the species’ tree of life.

“North America is one of the most-studied continents in terms of mammals, and carnivores are one of the most-studied groups,” says Adam Ferguson, one of the paper’s authors and the Negaunee collections manager of mammals at Chicago’s Field Museum. “Everyone thinks we know everything about mammalian carnivore systematics, so being able to redraw the skunk family tree is very exciting.”

Skunks are distantly related to dogs, and despite being part of the Carnivora order, they’re omnivores (capable of eating both plants and other animals). Striped skunks are more familiar to most people in North America because they’ve made their way to some urban and suburban areas. They’re also larger than the spotted ones, which tend to be smaller and enjoy staying out of sight when they can.

All skunks can spread a fetid liquid, but the smaller spotted skunks have the more spectacular display: they do a hand-stand on their front legs.

“Spotted skunks are sometimes called the acrobats of the skunk world,” says Ferguson.

Ferguson, McDonough, and colleagues analyzed DNA samples both from wild specimens and museum specimens, finding that some skunks that were once thought to be the same species were actually very different; sometimes, genetic differences don’t translate to visual differences.

[Also Read: The difference between a species and a subspecies – according to science]

Based on these genetic differences, they were able to regroup the spotted skunk group. In the process, they ended up bringing back species names that haven’t been used in centuries.

Important for conservation

Pretty cute. Image credits: Heidi Donat.

The diversification of spotted skunk species appears to have started relatively recently.

“By analyzing the genome of spotted skunks, we’ve been able to learn that their evolution and splitting into different species was driven by climate change during the Ice Age,” says Ferguson.

However, knowing what species a group has is important not just for building an evolutionary tree, but also for knowing which species are threatened by extinction. For instance, if what we thought was one species turns out to be two species, and one of them is doing just fine and the other is not, we could tailor conservation efforts to protect the endangered one.

This is also the case for some new species emerging from this study. For instance, the Plains spotted skunk has been known to be in decline for the past century. But conservationists thought this was a subspecies, not a full-fledged species.

“If a subspecies is in trouble, there’s sometimes less emphasis on protecting it because it’s not as distinct an evolutionary lineage as a species,” says Ferguson. “We’ve shown that the Plains spotted skunks are distinct at the species level, which means they’ve been evolving independently of the other skunks for a long time. Once something has a species name, it’s easier to conserve and protect.”

The study also offers a new opportunity for researchers to understand spotted skunks. Handstands aren’t the only unusual thing about them, researchers 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. “We want to know why some species have delayed implantation and others don’t, and figuring out how these different species of skunks evolved can help us do that.”

Journal Reference:  Phylogenomic systematics of the spotted skunks (Carnivora, Mephitidae, Spilogale): Additional species diversity and Pleistocene climate change as a major driver of diversification, Molecular Phylogenetics and Evolution, 2021.

The chemicals that make skunks and some marijuana smell the same

Credit: Flickr, Jon Nelson.

Due to countless iterations of cross-breeding, there are now more marijuana flavors than there are colors in the rainbow. Some are piney, some are lemony, and others still can smell like a whole fruit basket. But some strains don’t exactly smell like roses — in fact, the opposite is true in this case. The clearest example is skunk weed, which, as the name implies, smells like an angry skunk.

How can a plant smell like a mammal? It all has to do with terpenes, a class of aromatic chemicals found not just in cannabis, but in many other plants and even some insects.

Secreted in the same glands that produce cannabinoids like THC and CBD, terpenes are aromatic oils that are responsible for the taste and smell of cannabis — but that’s not all that they do.

Research suggests that cannabis terpenes play a considerable role in not only tempering the intoxicating effects of THC, but also creating synergy with phytocannabinoids and even increasing their therapeutic value. For instance, Professor Dedi Meiri and the Israel Institute of Technology are investigating marijuana terpenes as an anti-inflammatory agent to prevent the most severe, life-threatening cases of COVID-19.

There are at least 200 different terpenes in cannabis, although only a handful gives off a dominant aroma. Pinene is responsible for some strains’ pine-like fragrance, while caryophyllene is peppery. The skunky funk of some strains is due to myrcene, an earthy or musky terpene.

While a skunk’s defensive spray doesn’t contain terpenes, it has similar compounds called thiols. When these organic sulfurs mix together, they produce the potent, musky scent that people stay away from — unless it’s marijuana. That’s because skunky strains are also highly potent. In fact, in many parts of the world, the term “skunk weed” has taken on a more generic meaning, describing highly potent pot rather than the aroma of particular strains.

Because myrcene is the most abundant terpene in the cannabis plant, all strains will smell a bit like a skunk, although some strains are certainly more pungent than others. Some of the famous skunky strains include Golden Ticket and Death Star. If you really don’t like the smell of skunk, less smelly strains include Lemon Haze, Alpha Blue, Kali Mist, Orange Bud, and Northern Lights, according to WikiLeaf.

In the future, high-tech growers could infuse marijuana with a variety of different terpenes of their choosing. In 2017, researchers at the University of British Columbia, Canada, sequenced the genomes of various cannabis plants to see what particular genes give certain strains their characteristic flavors. They found 30 terpene synthase genes that contribute to the diverse flavors of cannabis, which could be manipulated to generate more consistent desirable smells. This is already underway in the wine industry for grape genes that encode enzymes for various flavors.

weed skunk

Smoking skunk might triple the risk of psychosis

South Londoners who smoke skunk weed – a much more potent strain of cannabis – were found to be three times more likely to register at hospitals with first-episode psychoses, according to a study made by British researchers. The research has many shortcomings though, as is to be expected from a case-control design where it’s always difficult to account for external variables. As the old saying goes, correlation does not equal causation, so take these findings with a grain of salt. The study is valuable however considering it’s among the few which actually considered the relationship between cannabis use and psychosis, often ignored by mainstream cannabis research. Cannabis is used by millions of people worldwide, yet its long-term effects are seriously under reported.

Stinky skunk weed

weed skunk

Credit: Marijuana Venture

Some people might confuse skunk as another slang term for cannabis, when in fact it’s a different strain altogether with much greater potency.  It has around two to three more times of the main active ingredient – tetrahydrocannabinol, or THC. Around 10% of all users will have an unpleasant experience with the drug, according to the Royal College of Psychiatrists. Long-term use of the drug can have a depressant effect, reducing a person’s motivation.

Links between increased incidents of psychosis among skunk users have been reported before, but interpretations have been mixed. Former government adviser Professor David Nutt wrote in 2009 that despite skunk being around for at least a decade, there had been no obvious rise in schizophrenia. In fact, he said, evidence shows psychosis and schizophrenia have been in decline among the British population, despite cannabis being used by a growing number of people over 30 years.

The latest report published in Lancet Psychiatry is based on scientists’ work with 410 patients, aged 18-65, who presented at south London hospitals with a first episode of psychosis. The patients exhibited schizophrenic behaviour such as hearing voices or suffering delusions for at least a month. To compare, the researchers identified a control group of 370 healthy participants from the same area, some of whom also smoked cannabis. They found that those with psychosis were much more likely to have used skunk every day, than to have never used cannabis. Interestingly enough, those who smoked hash every day were no more likely to have psychosis than people who never tried cannabis. Hash is thought of as a ‘cleaner’ cannabis, with around 5% THC, as opposed to 15% THC found in skunk.

Sir Robin Murray, professor of psychiatric research at King’s College London, warned however that the study doesn’t provide a causal link.

“The argument initially was that the people who are going to smoke cannabis are a bit odd anyway,” he said. “In south London, two-thirds of people have used cannabis and it seems unlikely that two-thirds of people are abnormal.”

Skunk and hash use were self-reported in this study, which means researchers had to rely on patients being good judges of how often they smoked, how much and, most importantly, what they smoked. Considering there are all sort of street smokes sold all over South London, like synthetic powerful highs known as “Spice”, the findings become even more controversial. A more refined, close to reality reporting would have been obtained if blood tests and analysis had been made.

Murray doesn’t discount the findings, however, and actually think hash should be recommended to hardcore smokers looking to quit. He likens the experience to alcohol abuse.

“You’re not going to go psychotic after a couple of puffs,” he said. “It’s like alcohol – drinking the odd glass of wine is fine, but if you’re drinking a bottle of whisky a day you’re heading for trouble.”

Some headlines in British newspapers today were in the lines of “one in four of all serious mental disorders caused by skunk”, but sensationalism aside if skunk does indeed cause an increased risk of psychosis, then more efforts should be made considering its widespread use, especially among teenagers. In this respect, the paper does make some steps forward.