How Climate Change Shaped This Adorable Skunk’s Evolution

The Field Museum/Robby Heischman
The Field Museum/Robby Heischman

If you’re like many people, you’ve often thought, “Boy, am I sure glad there are lots of types of spotted skunks.” (Us too.) And thanks to science, we now know whom to thank for this wonderful diversity: climate change. A report on the sweet-faced skunks’ strange history was published this week in the journal Ecology and Evolution.


Robert C. Dowler

The western spotted skunk (Spilogale gracilis) is a button-nosed, wee critter, maxing out at around just 2 pounds. To maximize its stench-dispersal powers, the skunk flings itself into a little handstand, waving its back legs and rear in the air as noxious gas sprays from a gland under its tail.


Jerry W. Dragoo

For all its exotic appeal, S. gracilis is surprisingly local, making its home up and down the left side of North America from the temperate rainforests of the Pacific Northwest to the hottest desert in Mexico.

Speciation, or the splitting of one species into two, usually happens when two populations of organisms are divided by some physical boundary, like a mountain or a waterfall. Because the two groups are living in slightly different environments, they face slightly different pressures, and eventually evolve into slightly different creatures.

To find out if that’s what happened with S. gracilis, the authors of the current study collected DNA samples from 97 skunks in a range of habitats and areas of the American Southwest.


Sampling skunks is odiferous work.
The Field Museum

They found that the skunks could be divided into three subtypes. But the subtypes aren’t separated by rivers or mountain ranges, nor have they ever been. Instead, the researchers say, the family was split up by climate change a very, very long time ago.

“Western spotted skunks have been around for a million years, since the Pleistocene Ice Age,” lead author Adam Ferguson, of The Field Museum and Texas Tech University, said in a statement. “During the Ice Age, western North America was mostly covered by glaciers, and there were patches of suitable climates for the skunks separated by patches of unsuitable climates.”

It was largely these shifting patches of hostile terrain that kept the skunk families apart. These findings are important not only for lovers of skunk history, but for scientists, conservationists, and policy-makers who care about where our planet and its inhabitants are going.

“What we know about the past can inform what we expect to see in the future,” says Ferguson. “Understanding these genetic subdivisions that happened as a result of changing climatic conditions can help us conserve skunks and other animals in the future.”

No Venom, No Problem: This Spider Uses a Slingshot to Catch Prey

Courtesy of Sarah Han
Courtesy of Sarah Han

There are thousands of ways nature can kill, and spider species often come up with the most creative methods of execution. Hyptiotes cavatus, otherwise known as the triangle weaver spider, is one such example. Lacking venom, the spider manages to weaponize its silk, using it to hurl itself forward like a terrifying slingshot to trap its prey.

This unusual method was studied up close for a recent paper published in the Proceedings of the National Academy of Sciences by researchers at the University of Akron in Ohio. They say it's the only known instance of an animal using an external device—its web—for power amplification.

Hyptiotes cavatus's technique is simple. After constructing a web, the spider takes one of the main strands and breaks it in half, pulling it taut by moving backwards. Then, it anchors itself to a spot with more webbing in the rear. When the spider releases that webbing, it surges forward, propelled by the sudden release of stored energy. In the slingshot analogy, the webbing is the strap and the spider is the projectile.

This jerking motion causes the web to oscillate, tangling the spider's prey further in silk. The spider can repeat this until the web has completely immobilized its prey, a low-risk entrapment that doesn’t require the spider to get too close and risk injury from larger victims.

The triangle weaver spider doesn’t have venom, and it needs to be proactive in attacking and stifling prey. Once a potential meal lands in its web, it’s able to clear distances much more quickly using this slingshot technique than if it crawled over. In the lab, scientists clocked the spider’s acceleration at 2535 feet per second squared.

Spiders are notoriously nimble and devious. Cebrennus rechenbergi, or the flic-flac spider, can do cartwheels to spin out of danger; Myrmarachne resemble ants and even wiggle their front legs like ant antennae. It helps them avoid predators, but if they see a meal, they’ll drop the act and pounce. With H. cavatus, it now appears they’re learning to use tools, too.

[h/t Live Science]

Bad News: The Best Time of the Day to Drink Coffee Isn’t as Soon as You Wake Up

iStock.com/ThomasVogel
iStock.com/ThomasVogel

If you depend on coffee to help get you through the day, you can rest assured that you’re not the world's only caffeine fiend. Far from it. According to a 2018 survey, 64 percent of Americans said they had consumed coffee the previous day—the highest percentage seen since 2012.

While we’re collectively grinding more beans, brewing more pots, and patronizing our local coffee shops with increased frequency, we might not be maximizing the health and energy-boosting benefits of our daily cup of joe. According to Inc., an analysis of 127 scientific studies highlighted the many benefits of drinking coffee, from a longer average life span to a reduced risk for cancer, heart disease, type 2 diabetes, and Parkinson’s disease.

Sounds great, right? The only problem is that the benefits of coffee might be diminished depending on the time of day that you drink it. Essentially, science tells us that it’s best to drink coffee when your body’s cortisol levels are low. That’s because both caffeine and cortisol cause a stress response in your body, and too much stress is bad for your health for obvious reasons. In addition, it might end up making you more tired in the long run.

Cortisol, a stress hormone, is released in accordance with your circadian rhythms. This varies from person to person, but in general, someone who wakes up at 6:30 a.m. would see their cortisol levels peak in different windows, including 8 to 9 a.m., noon to 1 p.m., and 5:30 to 6:30 p.m. Someone who rises at 10 a.m. would experience cortisol spikes roughly three hours later, and ultra-early risers can expect to push this schedule three hours forward.

However, these cortisol levels start to rise as soon as you start moving in the morning, so it isn’t an ideal time to drink coffee. Neither is the afternoon, because doing so could make it more difficult to fall asleep at night. This means that people who wake up at 6:30 a.m. should drink coffee after that first cortisol window closes—roughly between 9:30 a.m. and 11:30 a.m.—if they want to benefit for a little caffeine jolt.

To put it simply: "I would say that mid-morning or early afternoon is probably the best time," certified dietitian-nutritionist Lisa Lisiewski told CNBC. "That's when your cortisol levels are at their lowest and you actually benefit from the stimulant itself."

[h/t Inc.]

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