How Beavers Could Help Clean Up Polluted Waters Around the World

iStock.com/milehightraveler
iStock.com/milehightraveler

Beavers are a lot more impressive than you might think. These semiaquatic rodents can build dams as large as 2800 feet deep, thanks in part to their super sharp teeth and sturdy tails that keep them from tipping over while hauling heavy materials into the water. According to research from scientists at the UK-based University of Exeter, the animals could also potentially help clean up polluted waterways.

Professor Richard Brazier and his colleagues studied the water quality at the site of a fenced-in area in southwest England, where a family of captive beavers has been living since 2011. The water flowed from nearby fields to a local river, where it deposited sediment while passing through 13 dams that had been built by the beavers.

The reduced water flow—and the deep ponds that formed as a result of the dams—had a filtering effect. The beavers’ dams captured more than 100 tons of soil and other sediment that contained high levels of nitrogen and phosphorus, both of which are bad for wildlife and human consumption.

The runoff problem is also twofold: The erosion of soil on agricultural land has both economic and environmental consequences. Scientists suggest that the reintroduction of the Eurasian beaver to rivers could help curb some of this damage. These “ecosystem engineers,” as the animals are called in the University of Exeter study, were believed to have been hunted to extinction in Britain by the 1500s. However, a colony was found in Scotland a decade ago, and there have been some efforts since then to release beaver populations into the wild.

"It is of serious concern that we observe such high rates of soil loss from agricultural land, which are well in excess of soil formation rates,” Brazier said in a statement. “However, we are heartened to discover that beaver dams can go a long way to mitigate this soil loss and also trap pollutants which lead to the degradation of our water bodies. Were beaver dams to be commonplace in the landscape we would no doubt see these effects delivering multiple benefits across whole ecosystems, as they do elsewhere around the world."

In a separate study from 2015, scientists at the University of Rhode Island determined that larger beaver ponds were able to remove up to 45 percent of nitrogen in the water that passed through them, while smaller ponds removed roughly 5 percent. The North American beaver was also on the brink of extinction in the 1800s, but these populations have since rebounded in Rhode Island and other parts of the continent.

10 Ginormous Facts About Coconut Crabs

Janos/iStock via Getty Images
Janos/iStock via Getty Images

They're huge and antisocial. They will steal your silverware and can rip apart whole coconuts with their claws. Grab a piña colada and enjoy these 10 ginormous facts about the amazing coconut crab.

1. Coconut crabs are colossal.

Native to islands in the Indian and southern Pacific oceans, are truly humongous. They can weigh 9 pounds and measure 3 feet from leg to leg. Coconut crabs are the largest land-living arthropods—the phylum of joint-legged creatures that includes crabs, insects, spiders, and scorpions. Even Charles Darwin was stunned by their “monstrous size.”

But be aware: Occasionally, a viral photo circulates that exaggerates the coconut crab’s size. As biologist Michael Bok explains, the coconut crab in that infamous photo is normal sized, but the trash can is unusually small.

2. Coconut crabs are actually hermit crabs.

Coconut crab
Sandwich, Flickr // CC BY-NC-ND 2.0

Where does such a bizarre animal fit in the animal kingdom? Are they lobsters? Tarantulas? Space aliens? In fact, Birgus latro is a kind of hermit crab.

You may have seen smaller hermit crabs on a trip to the beach—or for sale at a pet shop. They take shelter inside abandoned snail shells, carrying them around as portable homes. But if coconut crabs are hermit crabs, then why don’t they live in shells? Well, they do—when they’re young and still small.

3. Coconut crabs quickly outgrow their borrowed shells.

Like other crabs, hatchling coconut crabs begin their lives floating freely at sea. After about a month of eating and growing, they find a snail shell and move in. The little coconut crabs carry this mobile home as they begin to transition to a land-based life.

A seashell is a nice, protected place to live, but it has its drawbacks [PDF]. As a crab gets bigger, its shell gets tighter—like an old pair of shoes on a kid who’s growing fast. The crab needs to find a bigger shell and make a quick switch. And that larger home will be heavier to tote around.

So, after a year or so of inhabiting shells, the coconut crab makes a major lifestyle change. It crawls out and hardens the parts of its body that were once protected by the shell by regrowing layers of calcium-based tissues, a process called recalcification. Without its old home, it’s free of size constraints. Now, unlike other hermit crabs, it can become enormous.

4. Coconut crabs eat coconuts, of course ...

This might seem obvious from the coconut crab’s name. But if you’ve ever tried to crack open a coconut, you know that it’s a steep challenge. In fact, a lengthy scientific debate once raged about whether coconut crabs were really able to open the fruit. It turns out that they’re up to the challenge—but they don’t just pop open their prize and dig in.

Breaking into a coconut is a mighty ordeal even if you’re a heavily armored crustacean the size of a small dog. Coconut crabs first use their claws to scrape away the fibrous coating. This can take hours or days. Finally, they stab into the fruit at a weak point and rip it open.

This diet helps coconut crabs grow large: those with access to coconuts may be twice as massive as those without. But eating the fruit isn’t essential for their survival. So what other items do the largest land-living arthropods shove into their maw?

5. ... but they also eat dead animals, their own body parts, and each other.

As well as the occasional biscuit, as you can see in the video above. (Note: Do not feed biscuits to coconut crabs.) A coconut crab’s diet may include other tropical fruits, fallen plant material, dead and decaying animals, rats, and other crab species. They’ll even eat members of their own kind. In fact, biologist Mark Laidre says they only relatively recently evolved to eat coconuts—a skill unique to modern coconut crabs—which helps them to eat each other less.

They also eat their own discarded body parts. As coconut crabs grow, they periodically molt their tough outer layer (the exoskeleton) and grow a new one. Once they’re done molting, which takes about a month, they gobble up their own exoskeleton.

6. Coconut crabs have an amazing sense of smell ...

Coconut crabs often forage at night. How do they find food when they’re wandering around in the dark? They sniff it out. These animals have a strong, highly efficient [PDF] sense of smell. In fact, a large portion of their brain is devoted to detecting odors.

7. ... which might explain why they're thieves.

Coconut crabs are also known as robber crabs because they snatch silverware and other objects and carry them away. Some people have even advanced the gruesome theory that Amelia Earhart’s remains are missing because coconut crabs hauled them down into their burrows. The thievery might be tied to that incredible sense of smell. Coconut crabs ignore objects that have been washed clean of scents, suggesting that they may only abscond with things that carry a faint whiff of food.

8. Coconut crabs are pretty antisocial.

Adult coconut crabs live alone in crevices or burrows. They aggressively guard their privacy; a crab entering another’s burrow risks becoming a meal.

But that’s not the end of their antisocial behavior. When coconut crabs emerge to feed, they keep their distance from each other. To maintain their personal space, they’ll announce their presence with ritualized claw waving. Laidre sought to find out if coconut crabs ever gathered together to interact (beyond mating or eating each other). The scientist tethered coconut crabs to one spot and watched to see if any others came to visit. They did not.

9. Coconut crabs carry their developing young under their abdomens.

After coconut crabs mate, females attach their eggs to special appendages and carry them under their abdomens. While the young develop inside the eggs, the females hold onto them, sticking near the edge of the sea so that they can periodically moisten the eggs.

But this care ends when the young are ready to hatch. The females release their hatchlings into the ocean waves. Now the tiny, floating babies must fend for themselves—and only a few will survive to return to land.

10. We need to learn a lot more about coconut crabs.

Coconut crab
Anne Sheppard, Wikimedia Commons // CC BY 3.0

Coconut crabs are little-studied creatures, and we need to know more about them—not just because they’re incredible and have a lot to tell us about biology, but also because we want to keep them around.

They may be huge and heavily armored, but they can be vulnerable. Coconut crabs take an extremely long time to grow big—they can live more than 40 years—and introduced predators such as rats can harm smaller, younger individuals or those in the process of shedding their exoskeletons (when their bodies are soft). Habitat loss has also caused local declines in some areas. The International Union for Conservation of Nature lists the coconut crab as data deficient: That is, we don’t know enough about its locations and populations. That’s why we need to study and learn more about these amazing, otherworldly critters.

‘Water’ in Kansas City Woman’s Ear Turned Out to Be a Venomous Brown Recluse Spider

N-sky/iStock via Getty Images
N-sky/iStock via Getty Images

Susie Torres, a resident of Kansas City, Missouri, woke up on Tuesday morning with the distinct feeling that water was lodged in her left ear. She likened it to the swooshing sensation that can often happen after swimming, WDAF-TV reports.

Instead of waiting for the problem to resolve itself, Torres went to the doctor—a decision that might have saved her from some serious pain. The medical assistant was the first to realize something was alarmingly amiss, and immediately called for backup.

“She ran out and said ‘I’m going to get a couple more people,’” Torres told 41 Action News. “She then said, ‘I think you have an insect in there.’” For many people, the thought of having any live insect stuck in an ear would be enough to cue a small- or large-scale freak-out, but Torres stayed calm.

The doctors “had a few tools and worked their magic and got it out,” Torres said. The “it” in question turned out to be a spider—and not just any harmless house spider (which you shouldn’t kill, by the way). It was a venomous brown recluse spider.

“Gross,” Torres told WDAF-TV. “Why, where, what, and how.”

Miraculously, the spider didn’t bite Torres. If it had, she would’ve ended up visiting the doctor with more than general ear discomfort: Brown recluse bites can cause pain, burning, fever, nausea, and purple or blue discoloration of the surrounding skin, according to Healthline.

Torres may have remained admirably level-headed throughout the ordeal, but that doesn’t mean she’s taking it lightly. “I went and put some cotton balls in my ears last night,” she told WDAF-TV. “I’m shaking off my clothes, and I don’t put my purse on the floor. I’m a little more cautious.”

Is this the first time an insect has posted up in the ear of an unsuspecting, innocent human? Absolutely not—here are six more horror stories, featuring a cockroach, a bed bug, and more.

[h/t WDAF-TV]

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