7 Facts About Nutria, the Invasive Rodents Taking Over Louisiana

Rodents of Unusual Size/Tilapia Film
Rodents of Unusual Size/Tilapia Film

Rodents are known for being pests, but the nutria may be the worst of them. The orange-toothed, semi-aquatic rodents from South America, which can grow to be up to 20 pounds, have become invasive species whose territory extends to almost every continent on earth. Along the way, they’ve created environmental catastrophes, destroyed infrastructure and crops, and created millions of dollars in damages. The pesky creatures are the subject of a new documentary, Rodents of Unusual Size. The 71-minute film traces the nutria’s rise in Louisiana and the profound consequences it has had on the ecosystem there. Here are seven facts about the animals we learned from the documentary.

1. THEY’RE NOT FROM AROUND HERE.

Nutria are native to South America, but over the past century or so, they have traveled around the globe. In some places, they’re better known as coypu, from the Spanish word coipú. (In Spanish, the word nutria means otter.)

While Rodents of Unusual Size focuses on a small community in southern Louisiana, nutria pose a significant problem elsewhere, too. In the late 19th and early 20th centuries, fur farmers and trappers brought them to Europe, Asia, and Africa as well as a number of places in North America to raise them for their pelts. (Some U.S. states also imported them as a method of weed control.) Unfortunately, that led to the rise of feral populations that have since ballooned. The Invasive Species Specialist Group has named nutria one of the world’s top 100 worst invasive species.

2. THEY MAKE A LOT OF BABIES.

One of the reasons nutria pose such a big problem as an invasive species is that they multiply rapidly. They reach sexual maturity at only a few months old, can reproduce up to three times a year, and in extreme cases, can have litters of up to 13. Though they typically only live between three and six years in the wild, they’re such prolific breeders that, as one invasive species project notes, even in that short time frame, “the amount of offspring produced is tremendous.”

3. AS AN INVASIVE SPECIES, THEY’RE REALLY BAD FOR THE ECOSYSTEM.

The snout of a nutria on a black background with the words 'Rodents of Unusual Size'

Growing up in Delacroix, an island community just south of New Orleans, “it was a jungle,” lifelong resident Thomas Gonzales explains in the opening minutes of Rodents of Unusual Size. “There was nothing but big oak trees. When I look out now, it looks like a disaster.”

Nutria, which can consume up to 20 percent of their body weight in plant matter and roots each day, eat up the vegetation that holds together wetland soil, causing major erosion. What was once wetland becomes open water, permanently. “All the grass that the muskrats used to eat, they cleaned it like a baseball field,” Gonzales says. “Now it’s all water.”

He’s not exaggerating. While storms, dredging, and other factors have also played a role in the environmental decline of places like Delacroix, between 2001 and 2016, overgrazing nutria contributed to the conversion of almost 26,800 acres of Louisiana marsh to open water, the state estimates. And since marshes serve as important protection against storm surges, that also leads to greater flooding inland.

Nutria also pose problems in other arenas: The animals dig extensive burrow systems that sometimes end up under roads, around bridges, and in canals and levees. They also destroy thousands of dollars worth of crops like sugarcane and rice each year, and do millions of dollars of damage to golf courses.

4. THEY WERE ONCE BIG BUSINESS.

The nutria’s rise to global domination is largely thanks to the fur industry. In Louisiana, for instance, fur farmers brought them up from Argentina to raise for their pelts in the 1930s. Some of those animals either escaped or were released, taking up residence along the Gulf Coast, where they flourished in the swamps and other wetlands. By the 1960s, nutria were the Louisiana fur industry’s biggest commodity, with trappers bringing in more nutria and selling the pelts for more money than any other animal. In the 1970s, nutria trapping brought in 1.9 million pelts per year [PDF]. Unfortunately, the overabundance of nutria meant that supply eventually outstripped demand—which was falling across the fur industry anyway—and prices fell steeply over the next few decades. Trapping nutria was no longer as profitable, so trappers found work elsewhere. And without the fur industry keeping the nutria in check, the animal's populations exploded.

5. PEOPLE STILL DEPEND ON THEM FOR THEIR LIVELIHOODS.

A man with a gun over his shoulder standing in a boat filled with nutria carcases
Thomas Gonzales of Delacroix Island, Louisiana

Now, as the environmental impact of nutria has become more apparent, the state of Louisiana is trying to bring back nutria trapping. In order to incentivize trappers to hunt down nutria, the state has a $5 bounty on nutria tails. During the nutria hunting season, from November to March, the state sets up collection stations where trappers can bring in the tails of nutria they have killed [PDF]. They get a check in the mail based on the number of tails they bring in, and can use the carcasses however they want—whether that’s selling them for their fur or meat or discarding them. (Sometimes fur dealers are even on hand at collection stations.) Since the program first began in 2002, it has resulted in the removal of 5 million nutria.

6. WEARING THEIR FUR IS CONSIDERED ETHICAL.

Nutria were originally valued for their pelts, and nutria fur may be making a comeback. In most of the world, killing nutria does a service to the environment, making the rodents one of the most ethical sources of fur around.

“Traditionally, the stigma of fur is that people don’t feel comfortable killing animals to adorn themselves,” fashion designer Cree McCree explains in the film. “But the thing with the nutria is that they’re being killed anyway, and they’re throwing these beautiful furs away. It seemed like a colossal waste.” So McCree founded Righteous Fur, a collective of fashion designers who incorporate nutria fur into their designs, making everything from coats and hats to bow ties. Since most faux fur is made of polyester or other plastics, wearing nutria might actually be more sustainable than sporting fake fur.

7. YOU CAN—AND SHOULD—EAT THEM.

A woman sits at a table covered in nutria pelts.
Cree McCree, founder of Righteous Furs

While people may be turned off by the idea of eating a giant rodent with big orange teeth, nutria actually make a pretty good addition to the dinner table, according to chefs and hunters. “If you approach it with an open mind, you’ll find it doesn’t have a really bad, swampy taste,” award-winning New Orleans chef Susan Spicer says in Rodents of Unusual Size. “The nutria flavor is sort of like the zucchini of the animal world. You can kind of make it work with a lot of different kinds of flavors.”

The meat is lean, and, unlike with other meats, you don’t have to worry about feeling bad that a cute critter died for your dinner. In fact, you’re doing the environment a service. And in the right hands, nutria is reportedly delicious. Some hunters in the film even say it’s preferable to steak.

Rodents of an Unusual Size makes its Los Angeles debut on September 14. To find a screening near you, check out the film’s website.

All images courtesy Rodents of Unusual Size/Tilapia Film

10 of the Most Popular Portable Bluetooth Speakers on Amazon

Altech/Bose/JBL/Amazon
Altech/Bose/JBL/Amazon

As convenient as smartphones and tablets are, they don’t necessarily offer the best sound quality. But a well-built portable speaker can fill that need. And whether you’re looking for a speaker to use in the shower or a device to take on a long camping trip, these bestselling models from Amazon have you covered.

1. OontZ Angle 3 Bluetooth Portable Speaker; $26-$30 (4.4 stars)

Oontz portable bluetooth speaker
Cambridge Soundworks/Amazon

Of the 57,000-plus reviews that users have left for this speaker on Amazon, 72 percent of them are five stars. So it should come as no surprise that this is currently the best-selling portable Bluetooth speaker on the site. It comes in eight different colors and can play for up to 14 hours straight after a full charge. Plus, it’s splash proof, making it a perfect speaker for the shower, beach, or pool.

Buy it: Amazon

2. JBL Charge 3 Waterproof Portable Bluetooth Speaker; $110 (4.6 stars)

JBL portable bluetooth speaker
JBL/Amazon

This nifty speaker can connect with up to three devices at one time, so you and your friends can take turns sharing your favorite music. Its built-in battery can play music for up to 20 hours, and it can even charge smartphones and tablets via USB.

Buy it: Amazon

3. Anker Soundcore Bluetooth Speaker; $25-$28 (4.6 stars)

Anker portable bluetooth speaker
Anker/Amazon

This speaker boasts 24-hour battery life and a strong Bluetooth connection within a 66-foot radius. It also comes with a built-in microphone so you can easily take calls over speakerphone.

Buy it: Amazon

4. Bose SoundLink Color Bluetooth Speaker; $129 (4.4 stars)

Bose portable bluetooth speaker
Bose/Amazon

Bose is well-known for building user-friendly products that offer excellent sound quality. This portable speaker lets you connect to the Bose app, which makes it easier to switch between devices and personalize your settings. It’s also water-resistant, making it durable enough to handle a day at the pool or beach.

Buy it: Amazon

5. DOSS Soundbox Touch Portable Wireless Bluetooth Speaker; $28-$33 (4.4 stars)

DOSS portable bluetooth speaker
DOSS/Amazon

This portable speaker features an elegant system of touch controls that lets you easily switch between three methods of playing audio—Bluetooth, Micro SD, or auxiliary input. It can play for up to 20 hours after a full charge.

Buy it: Amazon

6. Altec Lansing Mini Wireless Bluetooth Speaker; $15-$20 (4.3 stars)

Altec Lansing portable bluetooth speaker
Altec Lansing/Amazon

This lightweight speaker is built for the outdoors. With its certified IP67 rating—meaning that it’s fully waterproof, shockproof, and dust proof—it’s durable enough to withstand harsh environments. Plus, it comes with a carabiner that can attach to a backpack or belt loop.

Buy it: Amazon

7. Tribit XSound Go Bluetooth Speaker; $33-$38 (4.6 stars)

Tribit portable bluetooth speaker
Tribit/Amazon

Tribit’s portable Bluetooth speaker weighs less than a pound and is fully waterproof and resistant to scratches and drops. It also comes with a tear-resistant strap for easy transportation, and the rechargeable battery can handle up to 24 hours of continuous use after a full charge. In 2020, it was Wirecutter's pick as the best budget portable Bluetooth speaker on the market.

Buy it: Amazon

8. VicTsing SoundHot C6 Portable Bluetooth Speaker; $18 (4.3 stars)

VicTsing portable bluetooth speaker
VicTsing/Amazon

The SoundHot portable Bluetooth speaker is designed for convenience wherever you go. It comes with a detachable suction cup and a carabiner so you can keep it secure while you’re showering, kayaking, or hiking, to name just a few.

Buy it: Amazon

9. AOMAIS Sport II Portable Wireless Bluetooth Speaker; $30 (4.4 stars)

AOMAIS portable bluetooth speaker
AOMAIS/Amazon

This portable speaker is certified to handle deep waters and harsh weather, making it perfect for your next big adventure. It can play for up to 15 hours on a full charge and offers a stable Bluetooth connection within a 100-foot radius.

Buy it: Amazon

10. XLEADER SoundAngel Touch Bluetooth Speaker; $19-$23 (4.4 stars)

XLeader portable bluetooth speaker
XLEADER/Amazon

This stylish device is available in black, silver, gold, and rose gold. Plus, it’s equipped with Bluetooth 5.0, a more powerful technology that can pair with devices up to 800 feet away. The SoundAngel speaker itself isn’t water-resistant, but it comes with a waterproof case for protection in less-than-ideal conditions.

Buy it: Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

10 Facts About Argentine Ants

A pile of genetically-related Argentine ants
A pile of genetically-related Argentine ants
Marc Matteo, Flickr // CC BY-NC 2.0

A supercolony of invasive Argentine ants (Linepithema humile) stretches for 560 miles beneath California, from San Diego to San Francisco. The billions of Argentine ants are unlike other ants in many ways—and they are virtually indestructible. Along with their supercolonies in Europe, Japan, and Australia, L. humile’s global domination is rivaled only by that of human beings. Here’s what you should know about these prolific pests.

1. Argentine ant colonies are ruled by hundreds of queens.

Most ant colonies revolve around a single queen. Growing much larger than the worker drones, she is programmed to mate as quickly as possible, then to leave her nest of origin and establish a new one. In some species, a single queen can lay millions of eggs in a lifetime, producing an army of worker drones and future queens who will go off to build their own nests. But unlike most ants, Argentines are polygynous: Each nest contains multiple queens. In some, they can form up to 30 percent of the population.

2. Argentine ants move their nests frequently.

Nest types vary from ant species to ant species, but those who live in soil commonly dig tunnels and chambers deep into the earth that will protect the colony throughout the life of the queen. L. humile, though, is transient and ever shifting. Argentine ants frequently pack up their eggs and move the entire colony, queen and all, to a new nest, even when there is no apparent threat. Biologist Deborah Gordon told Ars Technica that the ants typically have 20 to 30 shallow nests at any one time, which can be built up in a matter of just weeks.

3. Argentine ants traveled the U.S. before settling down in California.

Argentine ants arrived in the United States from Northern Argentina in the late 19th century, when the first recorded Argentine ant was found in Louisiana in 1891. Researchers believe that the ants hitched a ride to North America in Argentinian shipments of coffee or sugar off-loaded at the Port of New Orleans. From there, they traveled—most likely by train—across the South and into California. Enticed by the Mediterranean climate, one similar to that of its original home in South America, the ants set up shop. By 1907, they’d displaced local native ants and begun their first steps towards total soil domination along 560 miles of California coastline.

4. California’s Argentine ants are more laid-back than their South American cousins.

In side-by-side comparisons of Argentine ants from their South American homeland and California, researchers have found that those from the West Coast are far more mellow than those from Argentina. In studies, it was typical for two ants from different nests to fight when placed in the same vial in Argentina, but in California, ants from different nests rarely fought, even when they were collected from locations several hundred miles apart.

A DNA study of ants from both locations in 2000 revealed a stark difference. In the ants from Argentina, microsatellites—short, uniquely patterned DNA sequences passed down from generation to generation—had more than twice as much variation as the microsatellites of the Californian ants. When two individuals from different nests in California were placed together, they recognized one another as family. The ants from Argentina didn’t, making them more likely to display territorial aggression.

The difference is rooted in the genetic bottleneck the ants encountered on their arrival to the Golden State over a century ago. According to biologist Neil D. Tsutsui, who conducted the DNA study, the ants in California today are all descendants of that founding colony. “It would be as if all of the people in the United States were descended from the Pilgrims who came here in 1620,” he told the Stanford Report in 2004. Instead of competing with one another, generation after generation has worked together to take out native ants and build an immense California colony.

5. Argentine ants protect other insects in exchange for sweet, sweet honeydew.

Argentine ants
Two Argentine ants share a tiny blob of honeydew.
Davefoc, Wikimedia Commons // CC BY-SA 4.0

Argentine ants love to feed on sweet nectar, but flowers and suburban kitchens aren’t the only source of such desirable foodstuffs. Insects that feed on plant sap, like mealybugs, scales, and aphids, naturally excrete sugar-rich liquid “honeydew” from their butts. To secure a steady flow of the sticky-sweet substance, Argentine ants will fight off the predators of their insect chefs, including soldier beetles and midges. They’ll even relocate their honeydew producers to better food sources or microclimates to get the most they can out of their anal secretions.

6. The California Argetine ant supercolony is one-sixth the size of Southern Europe’s.

The California supercolony, which scientists have named the “Californian large,” is only the second-biggest conglomeration of Argentine ants in the world. The biggest colony is found along Southern Europe’s Mediterranean coast, where it stretches 3700 miles from northern Italy to the Atlantic coast of Spain. The ants, introduced around 80 years ago, now number in the billions. Smaller supercolonies also exist in Japan and Australia.

7. Argentine ants are second only to humans in their scale of world domination.

In 2009, researchers discovered that Argentine ants from three of the world’s largest supercolonies (Southern Europe, California, and Japan) are so closely related that they actually form a single mega-colony. The study, led by Eriki Sunamura from the University of Tokyo, found that when placed together, ants from the three supercolonies refused to fight. Instead, they rubbed antennae in greeting the way L. humile does when interacting with genetically-related individuals.

The researchers believe that the Argentine ant mega-colony isn’t just the largest insect colony ever identified; it rivals that of human colonization around the globe. Presenting their findings in the journal Insect Sociaux, they wrote, “the enormous extent of this population is paralleled only by human society.”

8. A mass execution of Argentine ant queens takes place every spring.

Each spring, just before mating season begins, worker ants go on a killing rampage and assassinate 90 percent of their queens. Entomologists aren’t sure exactly why the large-scale execution occurs, but one hypothesis, published in the Journal of Evolutionary Biology in 2001, suggests that it is a “spiteful behavior” to kill the queens that are less related, on average, to the workers.

In their study, researchers from the University of Lausanne hypothesized that Argentine ants are regularly separated from direct family members through free exchange among the nests. Before mating season begins each year, those that are genetically related band together to kill more distantly related queens. Doing so decreases the nest’s genetic diversity and allows it to be rebuilt with a queen who is directly related to the greatest majority of workers.

The study’s results were inconclusive and the question remained unanswered, yet researchers learned something unexpected in the process. Instead of finding genetic diversity among worker ants, those belonging to each nest were actually a homogenous population. Only the queens were genetic outliers with relatively few familial relationships in each nest.

9. Climate change is making Argentine ants more of a nuisance to humans.

Argentine ants thrive in a Mediterranean climate where winters are cool and wet and summers are warm and dry. When conditions are ideal, they largely keep to themselves, but when conditions are drought-like or extremely wet, the ants move indoors in search of more hospitable climes. Experts at survival, Argentine ants can find food or water that’s been left unguarded in just minutes.

With the climate crisis, conditions in California are becoming more extreme. Hot days, no longer relegated just to the summer months, are becoming more numerous and prolonged. Droughts are becoming more frequent. While these changes are unlikely to harm much of the California supercolony, they are likely to drive the residents of urban nests more frequently into people's homes, making the ants a major nuisance for residents from San Diego to San Francisco.

10. Argentine ants are almost impossible to eradicate.

Individual Argentine ants are easy enough to kill, but an Argentine ant colony is a different story. The California colony has no natural predators and, thanks to their high levels of cooperation and massive numbers, L. humile has effectively destroyed possible competitors and disrupted the ecological balance of native species in the process. Insecticides, which are unable to penetrate into the underground nests, aren’t particularly effective. And because the ants can pick up and move their entire nest so quickly, neither are household control measures such as ant bait. After just over a century in California, Argentine ants are now virtually invincible.