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11 Invasive Species Wreaking Havoc Around the World

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Invasive species are bad news. They compete with native critters for food, destroy local ecology and, in some cases, are even dangerous to humans. And thanks to the increasingly global nature of our world, there are more and more animals discovered where they don’t belong every year. Here are just a few pests that have hitched rides to distant shores, where they’re currently wreaking havoc.

1. Cane Toad (Bufo marinus)

The cane toad (top) is perhaps the most infamous invasive species. Native to Central and South America, it has been imported to a number of places—Florida, the Phillippines, some Japanese islands, most islands in the Caribbean, and Hawaii, among other places—by farmers who hoped the creatures would wipe out local pests. Instead, they got another kind of pest, one that’s much harder to get rid of. The cane toad is huge—the biggest, captured in 2007, was over 8 inches long and weighed nearly two pounds—and voracious, gobbling up many native species.

The toxins in the cane toad's skin often kill animals that try to eat it (except for those animals who seem to deliberately get high by licking the toads), and it puts rabbits to shame with its reproductive capabilities; each female lays thousands of eggs each year. Case in point: Australia. In 1935, 102 cane toads were introduced to combat the Greyback Cane beetle. By 2010, that number had ballooned to 1.5 billion toads spread over 386,100 square miles, and they show no signs of stopping.

The toads are hardy, too: they’ve been spotted coming out of brush fires or hopping away after being run over. One toad even survived being eaten by a dog, which threw up the perfectly-fine toad 40 minutes later.

2. Asian Tiger Mosquito (Aedes albopictus)

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You’ll recognize this nasty bug, number four on the list of 100 worst invasive species, by the black and white markings on its body and legs. Native to Asia, it has spread to Europe, Africa, the Middle East and the United States—first in Hawaii in the 1800s, and then the continental U.S. in 1985, when it hitched a ride from Japan in a shipment of tires. Unlike most other mosquito species, the highly-adaptable Asian Tiger is active during the day, and lays its eggs either near stagnant water or in fresh running water. To nourish her eggs, the female feeds off of humans, birds and other animals with a rapid bite that allows her to eat and fly before she can be swatted.

The mosquito is a carrier of West Nile virus and dengue fever, among other diseases dangerous to people. Scientists in South America are experimenting with genetically modified versions of the males—which, when released into the wild, live just long enough to mate and pass on a lab-tweaked gene that kills the larvae shortly after they hatch—though the plan to introduce those modified bugs in Key West has been met with some protest.

3. Burmese Python (Python molurus bivittatus)

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Burmese pythons, native to Southeast Asia, came to the United States in the 1990s as part of the international pet trade. When those pets escaped their enclosures or were released into the wild, they bred, and the first established populations were reported in 2000. These massive snakes, which grow to an average of 12 feet (although larger ones have been found, and the snakes can grow to 20 feet in captivity), are eating their way through native species throughout Florida. Scientists believe they could eat Florida panthers, and at least one has tried to eat an alligator (albeit unsuccessfully: the snake exploded). It’s now illegal to import the snakes into the U.S. without a permit.

4. Brown Marmorated Stink Bug (Halyomorpha halys)

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If you live in certain portions of the United States, you might notice ugly, shield-like insects crawling and buzzing around your house. Squish or swat at them, and you’ll to get a noseful of foul stench. These obnoxious little pests are brown marmorated stink bugs. Native to Eastern Asia, they were first discovered in Allentown, Pennsylvania, in 1998, but likely arrived in shipping crates a few years before that. Since then, the bugs have spread to 34 states in the Northeastern U.S., the mid-Atlantic region and the Pacific Northwest. Halyomorpha halys eats almost anything it can get its proboscis on including apples, pears, soybeans, green beans, raspberries and cherries. And they’re destructive: In 2010, 18 percent of the mid-Atlantic apple crop was destroyed by the bugs. Brown marmorated stink bugs have few natural predators here, but scientists are exploring releasing non-stinging parasitoid wasps to help keep the stinkers in check. Researchers have also figured out where bugs that don’t come into your house spend the winter, which they hope will help control the population.

How do you get them out of your house? Bide your time. When it warms up, these stink bugs leave on their own. And, thankfully, they don’t lay eggs or nest in your walls—all of that behavior happens outside.

5. Asian Carp

The National Invasive Species Information Center lists four different species of Asian carp that have made their way into U.S. waters from Eurasia, where they compete with native species for food. One species, the silver carp, can also be dangerous to humans: The fish, which can grow to 100 pounds, are easily frightened by boats and frequently jump out of the water—sometimes onto people. According to a 2007 EPA report, “injuries include cuts from fins, black eyes, broken bones, back injuries, and concussions.” Some species have spread across the U.S.; it’s now illegal to import them without a permit.

6. Japanese Beetle (Popillia japonica)

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These clumsy fliers, native to Japan, probably came to the U.S. in a shipment of iris bulbs before 1912, when commodities inspections began. They were discovered in a Riverton, New Jersey, nursery in 1916 and have since spread as far as Idaho. The Japanese Beetle munches on 200 types of plants, including birch trees, rose bushes, grapes, and hops, consuming the leafy material between the veins.

7. Zebra Mussel (Dreissena polymorpha)

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The Zebra Mussel, native to Eurasia, came to North America in ship ballast water. They were first detected in the Great Lakes in 1988, and have spread like crazy since then. These tiny pests—which range from about the size of a fingernail to 2 inches in length—compete with native species for food, but they’re a headache for humans, too: They clog pipes and attach themselves to locks and dams. Dealing with the creatures costs millions of dollars a year.

8. Red Imported Fire Ant (Solenopsis invicta)

Public Domain, via Wikimedia Commons

If there’s one thing you don’t want to do, it’s accidentally stumble on a fire ant mound: These insects, native to South America, will swarm up your leg and sting in concert. Their venom, which contains a necrotizing alkaloid, isn’t typically strong enough to kill a person, but those stings hurt—a lot. The fire ant was introduced to the United States in the 1930s when it hitched a ride in ships’ ballast and has become a pest across the south. (There are also invasive populations in Taiwan and Australia.) Because they’re aggressive and extremely resilient—fire ants can survive both floods (by balling up into an ant raft) and droughts—they’re wiping out many native ants and lizard species; their mounds also destroy plant roots.

Stopping the invasion might seem impossible, but another non-native species might be able to help. In 1999, scientists released Phorid flies, imported from Brazil and Argentina, that lay eggs inside the fire ants. Their larvae eat the ant from the inside, and eventually pop out at the joint of the thorax and the head, decapitating the ant—and the new fly goes on to repeat the process.

9. Northern Snakehead Fish (Channa argus)

Photo Courtesy Virginia Tech

National Geographic didn’t call the Northern Snakehead “Fishzilla” for nothing: This species, native to China, can grow up to 40 inches long, has rows of slender, villiform teeth, and can breathe air—and, therefore, migrate over land. They have no predators outside their native habitat. The Northern Snakehead was first discovered in the U.S. in a pond in Maryland in 2002, where a man had released a pair of fish he had bought from a market in New York.

10. Asian Longhorn Beetle (Anoplophora glabripennis)

The so-called starry sky beetle might look pretty, but it’s also pretty destructive: It bores into both healthy and stressed maples and other hardwoods, weakening and killing the trees. Found in Brooklyn, New York in 1996, where it came in a shipment from Asia, this pest is currently in five states and threatens many others. The beetle also threatens trees in Austria, France, Germany, Italy, and the UK.

11. European Starling (Sturnus vulgaris)

You’ve seen them: the huge flocks of extremely noisy birds that alight from a tree, all at once, in a huge black cloud. These are European starlings, which were intentionally introduced in 1890 as part of a plan to bring to the United States all birds mentioned in the works of Shakespeare (starlings are mentioned in Henry IV, Part 1). According to Scientific American, the American Acclimatization Society released 100 starlings into Central Park in 1890 and 1891; by the 1950s, they had spread coast to coast. The birds compete with native species and destroy crops at every turn. So thanks for that, American Acclimatization Society!

This post originally appeared in 2012.

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This Self-Cloning Tick is Terrorizing More States
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Few arachnids are as demonized in the summer months as ticks, the parasitic little nuisances that can spread disease in humans and pets. That's not likely to change now that there's a exotic new species that can not only self-replicate, but is also poised to attack animals like a colony of swarming fire ants.

This super-tick is Haemaphysalis longicornis, or the longhorned tick, native to East Asia and imported to the U.S. by unknown means. The first North American sighting took place in August 2017 in New Jersey when a farmer walked into a county health office covered in nearly 1000 ticks after shearing a pet sheep that had been infested. The insect was then spotted in Virginia, West Virginia, and Arkansas, with caution advised in Maryland. As of this week, it’s now a confirmed resident of North Carolina, The Charlotte Observer reports.

H. longicornis invites more dread than a conventional tick for several reasons. It can “clone” itself, with females laying up to 2000 genetically identical eggs without any assistance from a male, a process called parthenogenesis. Reproduction is faster, with offspring appearing in just six months compared to two years for common deer ticks. It’s also an aggressive biter, nibbling on any animal flesh it can latch on to, and is able to transfer a host of diseases in the process—some of them fatal. In addition to Lyme, longhorned ticks can transmit the flu-like ehrlichiosis bacteria and the rare Powassan virus, which can cause brain inflammation.

The news isn’t much better for livestock. Given enough opportunity, the ticks can siphon enough blood from an animal to kill it, a process known as exsanguination. The attack can become so concentrated that pets have been spotted with ticks hanging from them like bunches of grapes.

New Jersey officials have confirmed the tick has survived the winter by burrowing underground, a somewhat ominous sign that the invasive species might be durable enough to become a widespread problem. Experts recommend taking all the regular precautions, including wearing long pants when outdoors, using repellent, and examining yourself and your pets for ticks. While the longhorned tick hadn’t yet displayed a taste for human flesh, it’s better to be safe than sorry. As for the sheep: following a chemical treatment, she made a full recovery.

[h/t Charlotte Observer]

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10 "Udderly" Fascinating Facts About Cows
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Cows dot fields and pastures across many countries, and cow products are valued and consumed worldwide because their production of milk and meat isn't seasonal, as crops usually are. Cow products can also be preserved for extended use, such as butter, cheese, and smoked or cured meats. And, scientists are still finding new uses for the roughly 80 pounds of manure that a dairy cow produces daily. Chew the cud over these 10 facts about bovines. 

1. COWS ARE KILLERS.

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An ABC News report cited a 2012 study, published in Wilderness and Environmental Medicine, which found that cattle cause an average of 22 deaths per year. Sharks, on the other hand, kill about six people per year. It sounds like SyFy should have made Cownado instead.

2. COW TIPPING IS JUST A MYTH.

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It might be funny to imagine a sleeping cow falling over with just a gentle shove, but cow tipping isn't that easy. Actually, it's nearly impossible. Cows sleep lying down and are generally wary of approaching humans, so they're never really blissed-out enough to allow a stranger to get close enough to touch them. But the bigger obstacle is their sheer size. Cows are massive—on average 1500 pounds—and balance their weight on all four legs.

3. COWS HAVE COMPLICATED DIGESTIVE SYSTEMS.

Cows eating hay in a row.
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Cows' stomachs are made up of four pouches—the reticulum, the rumen, the omasum, and the abomasum—each serving a specific purpose. Cows barely chew their food before it enters the first and largest part of the stomach called the rumen. Once the rumen is full, the cow lies down and the reticulum—which is made of muscle and is connected to the rumen so food and water can easily pass back and forth—pushes the unchewed food back up the esophagus and into the mouth. After re-chewing, or rumination, the food eventually passes through the omasum. The omasum filters out the water and gives the bacteria in the rumen more time to break down the food and take in more nutrients. Finally, the food enters the abomasum, which functions similar to a human stomach.

4. THERE ARE SURROGATE COWS.

Pregnant cow in a field.
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Transferring embryos from a genetically superior cow to a merely adequate cow is becoming more common. The procedure—known as embryo transfer (ET)—involves injecting a superior cow with hormones so she produces multiple eggs. Her eggs then need to be fertilized, either naturally or through artificial insemination. When the eggs are fertilized, a vet performs an "embryo flush" to remove them. That generally results in six to seven usable embryos, but can produce as many as 80 or 90. Without hormone treatment, a cow can only produce one embryo.

There are a number of reasons to perform ET—genetically superior cows produce genetically superior eggs. When they're transferred to surrogates, herds gain more powerful and efficient cows, instead of the offspring the surrogates might produce on their own. Embryos are also easily sent overseas to improve the bovine gene pool elsewhere, supplying more (and more efficient) milk-producing cows to countries that lack enough resources to meet demand. (For more on the cow surrogacy process, check out this story from NPR's Abby Wendle.)

5. THE ORIGIN OF THE WORD CATTLE STEMS FROM THE WORD FOR PERSONAL PROPERTY.

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According to the Merriam-Webster dictionary, the origin of cattle is chatel, the Anglo-French word for personal property. Chatel comes from the Medieval Latin term capitale.

6. A COW IS TECHNICALLY A FEMALE WHO HAS GIVEN BIRTH TO AT LEAST ONE CALF.

Mother cow licking a baby calf.
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There are specific terms for bovines depending on their age, sex, and purpose. For example, a "bull" is a mature, male bovine used for breeding, while a "steer" is a male that's been castrated and is used for its beef. A "heifer" is a female bovine that has yet to have calves, and a "bred heifer" is a pregnant heifer. There are a number of additional terms that farmers use to describe members of their herd.

7. BULLS CAN'T SEE RED.

A matador in the arena with a bull.
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A bullfighter could just as easily wave a pink or purple flag to get a bull to charge. The bull isn't angered by the color—all bovines are red/green colorblind. Instead, it's the movement of the cloth that gets it all riled up. The real reason matadors wear red: to hide the bull's blood.

8. COWS WITH NAMES PRODUCE MORE MILK.

A cow being milked.
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If farmers have a good relationship with their cows—meaning they give them names and show enough affection—they can produce more milk than their lonely counterparts. A 2009 study from Newcastle University found that cows who are more comfortable around humans are less stressed when milked. When cows are stressed, they produce cortisol, a hormone that inhibits milk production.  Another plus side of a happy cow-human relationship: farmers are less likely to get injured on the job (see fact #1).

9. INTO THE WOODS USED A REAL COW.

James Corden on stage in a white jacket
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For the 2014 film, director Rob Marshall wanted to use a real, live cow instead of depending on CGI. James Corden, who played the Baker and spent plenty of time with his bovine costar, admitted that things didn't always go smoothly: "You just don't know what it's like when you're doing a scene, and Meryl Streep is giving a phenomenal performance in only the way she can and it's scuppered by just 'Moooooooo,'" he recalled, adding, "That cow was the biggest diva on this set."

10. COWS PRODUCE METHANE, BUT DON'T BLAME THEM FOR GLOBAL WARMING.

Cows in a rounded milking station.
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Even though cattle produce plenty of methane during digestion, the United States Environmental Protection Agency (EPA) still considers the animals' contribution to global warming our fault, "because humans raise these animals for food and other products." In other words, this is a classic case of "He who smelt it, dealt it."

This story originally ran in 2015.

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