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Watch a "Trained" Spider Named Kim Leap Six Times Its Body Length

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Jumping spiders are cold-blooded assassins, masters of disguise, and just maybe a little quicker on the uptake than we're really OK with. For a study published in the journal Scientific Reports, a team of researchers from the University of Manchester "trained" one special jumping spider named Kim to leap in their experiment, all with the goal of demystifying the mechanics behind jumping spiders' abilities.

Kim was one of four regal jumping spiders (Phiddipus regius) the researchers brought into the lab for a close examination of how their bodies move as they leap and land. A jumping spider can clear up to six times its body length, which ranges from 0.04 to 0.98 inches—about the equivalent of a three-story building, relative to the spider's body size. For comparison, the farthest a human can jump is roughly 1.5 body lengths.

The researchers created an experiment chamber with platforms at varying distances from one another, then tried to coax the spiders into it. Only Kim would even enter. The researchers moved Kim between the take-off and landing platforms until she "became familiar with the challenge," they write. No tasty bait or stimulation (like blowing air) was used to motivate her. Still, her eventual familiarity with the task potentially implies some sort of learning. So even though she wasn't following orders, she figured out how to navigate the experiment's challenges—an impressive achievement for a spider about the size of an aspirin.

Using ultra-high-speed and high-resolution cameras, the researchers then filmed Kim's jumps to study how the arachnid moved her body when navigating a short jump equal to two body lengths; a longer jump equal to six lengths; and jumps between platforms placed at different heights. They found that Kim cleared shorter distances quickly and at low angles, thus sharpening her accuracy and boosting her chances of catching any prey that might be waiting at her destination. For longer jumps, she was more conservative with her energy, but her accuracy suffered.

Jumping spiders are excellent hunters, thanks in part to their precision ambushing skills. They also boast super-powered senses that help them locate their next meal before making their attack. Fine hairs on their legs allow them to "hear" subtle vibrations, and their eight eyes are sharp enough to track laser pointer lights.

This family of spiders also uses a hydraulic pressure system to move their legs. It helps jumping spiders extend their limbs, and some researchers have theorized that it also allows them to jump such great distances. According to the new study, that's not the case: "Our results suggest that whilst Kim can move her legs hydraulically, she does not need the additional power from hydraulics to achieve her extraordinary jumping performance," study co-author Bill Crowther said in a press statement. That means the jumps in the video below are made possible by Kim's muscle power alone.

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Big Questions
What Causes Sinkholes?
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Mark Ralston/AFP/Getty Images

This week, a sinkhole opened up on the White House lawn—likely the result of excess rainfall on the "legitimate swamp" surrounding the storied building, a geologist told The New York Times. While the event had some suggesting we call for Buffy's help, sinkholes are pretty common. In the past few days alone, cavernous maws in the earth have appeared in Maryland, North Carolina, Tennessee, and of course Florida, home to more sinkholes than any other state.

Sinkholes have gulped down suburban homes, cars, and entire fields in the past. How does the ground just open up like that?

Sinkholes are a simple matter of cause and effect. Urban sinkholes may be directly traced to underground water main breaks or collapsed sewer pipelines, into which city sidewalks crumple in the absence of any structural support. In more rural areas, such catastrophes might be attributed to abandoned mine shafts or salt caverns that can't take the weight anymore. These types of sinkholes are heavily influenced by human action, but most sinkholes are unpredictable, inevitable natural occurrences.

Florida is so prone to sinkholes because it has the misfortune of being built upon a foundation of limestone—solid rock, but the kind that is easily dissolved by acidic rain or groundwater. The karst process, in which the mildly acidic water wears away at fractures in the limestone, leaves empty space where there used to be stone, and even the residue is washed away. Any loose soil, grass, or—for example—luxury condominiums perched atop the hole in the ground aren't left with much support. Just as a house built on a weak foundation is more likely to collapse, the same is true of the ground itself. Gravity eventually takes its toll, aided by natural erosion, and so the hole begins to sink.

About 10 percent of the world's landscape is composed of karst regions. Despite being common, sinkholes' unforeseeable nature serves as proof that the ground beneath our feet may not be as solid as we think.

A version of this story originally ran in 2014.

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DNA Analysis of Loch Ness Could Reveal the Lake's Hidden Creatures
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Stakeouts, sonar studies, and a 24-hour video feed have all been set up in an effort to confirm the existence of the legendary Loch Ness Monster. Now, the Associated Press reports that an international team of scientists will use DNA analysis to learn what's really hiding in the depths of Scotland's most mysterious landmark.

The team, led by Neil Gemmell, who researches evolutionary genetics at the University of Otago in New Zealand, will collect 300 water samples from various locations and depths around the lake. The waters are filled with microscopic DNA fragments animals leave behind as they swim, mate, eat, poop, and die in the waters, and if Nessie is a resident, she's sure to leave bits of herself floating around as well.

After extracting the DNA from the organic material found in the water samples, the scientists plan to sequence it. The results will then be compared to the DNA profiles of known species. If there's evidence of an animal that's not normally found in the lake, or an entirely new species, the researchers will hopefully spot it.

Gemmell is a Nessie skeptic, and he says the point of the project isn't necessarily to discover new species. Rather, he wants to create a genetic profile of the lake while generating some buzz around the science behind it.

If the study goes according to plan, the database of Loch Ness's inhabitants should be complete by 2019. And though the results likely won't include a long-extinct plesiosaur, they may offer insights about other invasive species that now call the lake home.

[h/t AP]

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