'Glacier Mice' Are Scampering Balls of Moss

It’s midday on Iceland’s Falljökull glacier, and all is still. The landscape is impressive, but simple: broad brushstrokes of ice, rock, and sky.

The wind picks up. But there are no trees with rustling leaves here, no bird to catch an updraft. Not a creature is stirring—except for a mouse. Propelled by a blast of wind, a baseball-sized ball of moss called a glacier mouse scoots across the ice.

From a distance, the glacier mouse brings to mind a fuzzy, dense tumbleweed. But, scientists have learned, it’s really more like a mobile home: Each glacier mouse provides lodging, food, and transportation for hundreds of tiny organisms.

Nothing happens quickly around here, and the birth of a glacier mouse is no exception. It begins with a small pebble, furred with a moustache of moss. As the moss spreads, it insulates the pebble against the cold. The ice beneath it begins to melt. Eventually, the now moss-covered pebble balances on a spire of ice. A gust of wind knocks the newly minted glacier mouse off its pedestal and into motion for the first time.

It was the glacier mouse’s impressive powers of insulation that first led scientists to suspect its busy inner life. Biologist Steve Coulson, of the University Center in Svalbard, and his colleague Nicholas Midgley, of Nottingham Trent University, knew that the Racomitrium moss could absorb water and keep out the cold. Did other organisms know this? There was only one way to find out.

The scientists stuck thermometers in five glacier mice to monitor their internal temperatures and brought 10 others back to the lab. Coulson pulled the moss balls apart, hoping to find a few inhabitants. He found more than a few.

The tally, as Coulson and Midgley reported in the journal Polar Biology, was impressive: 73 bug-like animals called springtails, 200 tardigrades, and 1000 nematode worms—all in a single mouse.

Not only did the researchers find these critters, but they found them at all stages of development, which suggests they’re breeding within. And why wouldn’t they? They’ve managed to find a cozy, well-stocked den. The average temperature on the glacier was about 32°F. But inside the mouse, temperatures stayed toasty, between 36°F and 50°F.

There’s another advantage to life inside the glacier-mouse Catbus: travel. The glacier-hopping moss balls carry their passengers to exciting new locations (which, to a springtail, might mean that lump of ice over there).

Herds of glacier mice are best known in Iceland, but they’ve been spotted on the glaciers of several countries. The next time you find yourself trekking across a vast glacial expanse (you know, whenever), take a look at the scenery around you. If the glacier mice can teach us anything, it’s that even the humblest among us contains multitudes.

Photographs of glacier mouse herds courtesy of Darrel A. Swift, University of Sheffield.

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This Plant Can Burn Your Skin With Its Sap—And It May Be Coming to Your Neighborhood
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It's huge, it's extremely dangerous, and it's spreading. The giant hogweed (Heracleum mantegazzianum) contains a corrosive sap that causes severe rashes, third-degree burns, and even permanent blindness if you get the photosensitive chemicals on your skin or in your eyes, Science Alert reports.

The noxious, invasive weed was just identified in Clarke County, Virginia, near the Massey Herbarium at Virginia Tech. That brings the number of states it's been spotted in to 11, including Washington, Oregon, Illinois, Michigan, North Carolina, Pennsylvania, New York, Connecticut, Massachusetts, and Maine. Beyond the U.S., it has taken root all over the world, from the UK to Iceland to Australia.

Similar to the common but slightly less dangerous cow parsnip, giant hogweed is native to Central Asia and was first brought to North America in the early 1990s as an ornamental plant, its unique shape making it popular among gardeners. But it soon became invasive: Once it’s established in an area, it can take up to five years to eradicate a colony.

Now the plant is considered a public health concern. Hogweed can cause a reaction known as phytophotodermatitis when it comes into contact with skin that is subsequently exposed to UV rays—but the effects of hogweed are much more severe. A painful blister can develop within hours and last for months; the exposed skin can remain sensitive to sunlight for years even after the blisters heal.

Hogweed can be difficult to distinguish from the cow parsnip, and the plant is often misidentified. First, check for height: Hogweeds are typically taller than 8 feet, while cow parsnip tends to be 5 to 8 feet tall. Hogweed stems are green with purple specks and coarse white hairs, while parsnip stems are green with fine white hairs. For more tips and photos, check out the New York Department of Environmental Conservation’s guide.

If you see a plant you think might be a giant hogweed, take a few photos and send them to your state's department of agriculture to identify—and whatever you do, don't touch it.

[h/t Science Alert]

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How to Spot Poison Ivy, According to a Scientist
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If you're a former scout, you've probably heard the rhyme “leaves of three, let it be.” This mnemonic device, used to steer intrepid outdoorspeople away from poisonous ivy and oak, is generally sound advice for ensuring you don’t come home with a nasty rash. Not all three-leaved plants are the enemy, though, and several harmless plants are often confused with poison ivy.

Microbiologist John Jelesko shared some tips with NPR for identifying this pernicious plant. First, it helps to know what you’re up against. Poison ivy is a master of disguise and can take many different shapes and sizes. It can appear in small patches, take the form of creeping vines or a bush, and can even mimic the appearance of a tree it has wrapped itself around. The leaves can have either “smooth, jagged, or lobed edges” and may or may not bear white or greenish berries.

If the plant has thorns, you can be sure it’s not poison ivy, whose mode of attack is a little more stealthy. In the city, Jelesko had found that climbing vines are the more common form; look out for ground-creeping vines in forested areas. While there are exceptions to this rule, Jelesko’s research found that poison ivy tends to take different forms depending on the landscape.

A longer middle stem and a hairy vine are also signs that you could be dealing with poison ivy. If you have a plant in your garden that you can’t identify, you can conduct a “black dot test” to see if it’s poison ivy. Put on a pair of gloves, tear a leaf in half, and place the sap on a sheet of white paper. If it’s urushiol oil (the rash-causing chemical in poison ivy), it will turn black within 30 minutes.

Sometimes, even our best efforts to identify poison ivy may fail. If you think you may have brushed up against it, don’t panic—take a shower within a few hours of contact. That should keep your chance of developing a rash at a minimum.

[h/t NPR]

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