CLOSE
iStock
iStock

15 Shucking Amazing Facts About Oysters

iStock
iStock

Oysters are slimy, yet delicious. Casanova purportedly ate 50 of them for breakfast daily—and he isn’t the only one who believed they had certain powers. Oysters are definitely key to healthy marine ecosystems and clean water. Here are 15 facts about these ugly yet amazing shellfish.

1. THEY'RE BETTER WATER FILTERS THAN BRITA BY FAR.

Every day, one oyster filters 50 gallons of water and a healthy one-acre reef around 24 million gallons—enough to fill 36 Olympic swimming pools. Here’s how that works. An oyster draws water in over its gills using cilia, or tiny hairs. Plankton and particles in the water are trapped in mucus in the gill, then transported to the oyster’s mouth. So, yeah, oysters basically eat their own snot but, at the same time, remove excess sediment, nutrients, and algae from the water. That keeps the water in good shape for other marine life.

2. THEY DEVELOP NEIGHBORHOOD COMMUNITIES.

A close-up image of a Gulf Coast oyster bed taken in 2007 for a federal ecosystem restoration initiative. Image credit: EPA via Wikipedia Commons // Public Domain 

Oysters form beds or reefs that provide important habitat for fish and other creatures, including sea anemones and barnacles, which in turn provide food for bigger fish such as striped bass, black drum, and croaker. That works out to 1.5 extra tons of seafood a year.

3. SPRING IS WHEN A YOUNG OYSTER LOOKS FOR LOVE.

Oysters spawn when water temperatures rise in spring. Females release millions of eggs and males even more sperm and some of these lucky gametes meet in the open water. Fertilized eggs develop into microscopic larvae, little more than tiny black specks, which feed on algae, drifting on currents and tides for three weeks. Then, if something else hasn’t eaten them, the larvae attach to a hard surface, most likely other oysters, and transform into a tiny oyster called a spat. In areas where reefs have declined, oyster larvae may never find a place to settle.

4. THEY HOLD BACK FIERCE WAVES. 

Oyster reefs provide an effective natural barrier to storm waves and sea level rise. They absorb as much as 76 to 93 percent of wave energy, which reduces erosion, flooding, and property damage from coastal storms. Oyster reefs are preferable to manmade rip-rap or bulkheads, which don’t provide other benefits, such as habitat, and cost a lot to maintain. According to a Mississippi-Alabama Sea Grant Consortium report, 100 miles of oyster reefs could save up to $95 million on rip-rap or $150 million on bulkheads.

5. FORGET THE 'R' POLICY—OYSTERS ARE GOOD FOR YOU YEAR-ROUND.

Oysters are high in zinc, which is good for your immune system, and also provide calcium, vitamin C, omega 3 fatty acids, iron, and protein. Jason Hedlund, seafood coordinator for Whole Foods Markets, told mental_floss that oysters are low in cholesterol as well. “And that old rule about only eating oysters in months with an ‘R’ in them no longer applies, thanks to developments in food safety,” he added. 

6. IRRITATION LEADS TO BEAUTY AND VALUE.

Not an accurate representation of how pearls are found in oysters. Image credit: iStock

Closely related to the food oysters (family Ostreidae) are the pearl oysters (family Aviculidae). When any small irritant such as a grain of sand gets inside an oyster shell, the animal covers it with nacre, or mother-of-pearl, the substance that forms the inside lining of the shell. Over several years, as more layers are added, a pearl forms. The type, color and shape of a pearl depend on pigment in the nacre and the shape of the original irritant. Today, most pearls are cultured, or created in farmed oysters. Cultured pearls look just like natural ones but are considered less valuable.

7. BAD NEWS: OYSTER REEFS ARE GREATLY IMPERILED WORLDWIDE.

Oyster reefs are the single most imperiled marine habitat on Earth, with 85 to 90 percent of wild reefs lost. The main culprit is destructive fishing practices, including overharvesting, according to a report from The Nature Conservancy, along with habitat loss and declining water quality.

8. GOOD NEWS: REEF RESTORATION WORKS.

Fortunately, oyster reef restoration efforts are very successful. Some 80 restoration projects are currently underway around the U.S., including Nature Conservancy projects in Texas, Louisiana, Mississippi, Alabama, Florida, Georgia, South Carolina, and North Carolina.  Monitoring of these projects has shown as much as 212 percent increases in oyster growth and 850 percent increases in other marine life on the reefs. NOAA is involved in oyster reef restoration in Chesapeake Bay, where native populations had plunged to 1 percent of historic levels.

A study in the Journal of Applied Ecology reviewed literature on the increase in juvenile fish and mobile crustaceans in Crassostrea virginica reefs in the US and found increased production for 19 and 12 species, respectively, in the Gulf of Mexico and in the South and Mid-Atlantic.

9. WE CAN GET CREATIVE WITH REPAIRING THEIR HOMES.  

Marsh grass and oyster beds. Image credit: Steve Hillebrand, U.S. Fish and Wildlife Service, via Wikimedia Commons // Public Domain

A variety of techniques work for oyster reef restoration, from shooting oyster shell from high-pressure hoses to placing bags of shells in the water. Some projects have built lines of shell and rock to stabilize the shoreline along with planting sea grass behind the reef to provide additional habitat. In areas without existing structure for "spat set" (a good location for young oysters, a.k.a. spat), seed oysters from hatcheries are used to establish new reefs.

10. OYSTERS DON'T HAVE FUN ON ACID.

As the oceans absorb more carbon dioxide, it changes the chemistry of the water. The world’s oceans have become 30 percent more acidic since the start of the Industrial Revolution, and that can kill oyster larvae and make it harder for oysters to form shells. 

11. HARVESTING OYSTERS THE RIGHT WAY DOESN'T HARM OTHER SPECIES.

The Monterey Bay Aquarium Seafood Watch rates Eastern oysters from Alabama, Louisiana, Mississippi, Texas, and Florida caught by dredge or tong as "Best Choices." The oyster harvest has no bycatch—other species of marine life caught along with the intended target. Seafood Watch recommendations “help you choose seafood that’s fished or farmed in ways that have less impact on the environment,” according to the organization.

12. THERE ARE FIVE SPECIES IN U.S. WATERS.

A 1910 map of public oyster beds in Virginia's James River. Image credit: Wikimedia Commons // Public Domain

Oysters are found on the East, West, and Gulf Coasts of the US. Crassostrea virginica, the Eastern oyster, ranges from Canada to Key Biscayne, Florida, and throughout the Gulf of Mexico. Ostreola conchaphila is native to the West Coast, where farmed reefs also contain the widely cultivated Pacific or Japanese oyster, Crassostrea gigas. Two more oysters are grown for specialty markets: the European Flat oysters (Ostrea edulis) and Kumamatos (Crassostrea sikamea).

13. ALL YOU NEED IS THE RIGHT KNIFE. OR BACON.

Raw, grilled, fried, wrapped in bacon, mixed into dressing, in soup, casserole or stew—oysters can be eaten just about any way you can think of. Whole Foods seafood coordinator Jason Hedlund calls them a hyper-local seafood, telling mental_floss, “Oysters reflect the bay they come from, almost like a terroir.” Anyone with the right knife and gloves can shuck their own oysters. Watch this video with George Hastings, a national oyster shucking champion (yes, there is such a thing). 

14. OIL IS LETHAL TO OYSTERS AT ALL STAGES OF LIFE.

Oyster production in the Gulf of Mexico declined each of the four years following the BP oil spill disaster. A report from the National Wildlife Federation, Five Years and Counting, states “…oyster eggs, sperm and larvae were exposed to oil and dispersants during the 2010 oil spill. [Polycyclic aromatic hydrocarbons] can be lethal to oyster gametes, embryos, larvae, juveniles and adults. They can also have sub-lethal effects, such as reduced reproductive success.” Unable to move away from such contamination, sedentary oysters are particularly susceptible.

15. SORRY, YOU'RE GOING TO HAVE TO RELY ON YOUR CHARM.

There is little, if any, truth to the idea that oysters are an aphrodisiac. They contain phosphorus and iodine, which may increase human stamina, and zinc aids in production of testosterone. American and Italian researchers found that a type of mussel related to oysters contains two rare amino acids: D-aspartic acid and N-methyl-D-aspartate, which have been shown to increase sperm motility and stimulate testosterone in mice. But no studies have looked at whether that translates to increased libido. As one of the researchers, George Fisher, professor of chemistry at Barry University, told mental_floss, “To my knowledge, the old-wives tale of eating oysters to improve libido has no sustainable, scientific proof.”

nextArticle.image_alt|e
Penn Vet Working Dog Center
arrow
Stones, Bones, and Wrecks
New Program Trains Dogs to Sniff Out Art Smugglers
Penn Vet Working Dog Center
Penn Vet Working Dog Center

Soon, the dogs you see sniffing out contraband at airports may not be searching for drugs or smuggled Spanish ham. They might be looking for stolen treasures.

K-9 Artifact Finders, a new collaboration between New Hampshire-based cultural heritage law firm Red Arch and the University of Pennsylvania, is training dogs to root out stolen antiquities looted from archaeological sites and museums. The dogs would be stopping them at borders before the items can be sold elsewhere on the black market.

The illegal antiquities trade nets more than $3 billion per year around the world, and trafficking hits countries dealing with ongoing conflict, like Syria and Iraq today, particularly hard. By one estimate, around half a million artifacts were stolen from museums and archaeological sites throughout Iraq between 2003 and 2005 alone. (Famously, the craft-supply chain Hobby Lobby was fined $3 million in 2017 for buying thousands of ancient artifacts looted from Iraq.) In Syria, the Islamic State has been known to loot and sell ancient artifacts including statues, jewelry, and art to fund its operations.

But the problem spans across the world. Between 2007 and 2016, U.S. Customs and Border Control discovered more than 7800 cultural artifacts in the U.S. looted from 30 different countries.

A yellow Lab sniffs a metal cage designed to train dogs on scent detection.
Penn Vet Working Dog Center

K-9 Artifact Finders is the brainchild of Rick St. Hilaire, the executive director of Red Arch. His non-profit firm researches cultural heritage property law and preservation policy, including studying archaeological site looting and antiquities trafficking. Back in 2015, St. Hilaire was reading an article about a working dog trained to sniff out electronics that was able to find USB drives, SD cards, and other data storage devices. He wondered, if dogs could be trained to identify the scents of inorganic materials that make up electronics, could they be trained to sniff out ancient pottery?

To find out, St. Hilaire tells Mental Floss, he contacted the Penn Vet Working Dog Center, a research and training center for detection dogs. In December 2017, Red Arch, the Working Dog Center, and the Penn Museum (which is providing the artifacts to train the dogs) launched K-9 Artifact Finders, and in late January 2018, the five dogs selected for the project began their training, starting with learning the distinct smell of ancient pottery.

“Our theory is, it is a porous material that’s going to have a lot more odor than, say, a metal,” says Cindy Otto, the executive director of the Penn Vet Working Dog Center and the project’s principal investigator.

As you might imagine, museum curators may not be keen on exposing fragile ancient materials to four Labrador retrievers and a German shepherd, and the Working Dog Center didn’t want to take any risks with the Penn Museum’s priceless artifacts. So instead of letting the dogs have free rein to sniff the materials themselves, the project is using cotton balls. The researchers seal the artifacts (broken shards of Syrian pottery) in airtight bags with a cotton ball for 72 hours, then ask the dogs to find the cotton balls in the lab. They’re being trained to disregard the smell of the cotton ball itself, the smell of the bag it was stored in, and ideally, the smell of modern-day pottery, eventually being able to zero in on the smell that distinguishes ancient pottery specifically.

A dog looks out over the metal "pinhweel" training mechanism.
Penn Vet Working Dog Center

“The dogs are responding well,” Otto tells Mental Floss, explaining that the training program is at the stage of "exposing them to the odor and having them recognize it.”

The dogs involved in the project were chosen for their calm-but-curious demeanors and sensitive noses (one also works as a drug-detection dog when she’s not training on pottery). They had to be motivated enough to want to hunt down the cotton balls, but not aggressive or easily distracted.

Right now, the dogs train three days a week, and will continue to work on their pottery-detection skills for the first stage of the project, which the researchers expect will last for the next nine months. Depending on how the first phase of the training goes, the researchers hope to be able to then take the dogs out into the field to see if they can find the odor of ancient pottery in real-life situations, like in suitcases, rather than in a laboratory setting. Eventually, they also hope to train the dogs on other types of objects, and perhaps even pinpoint the chemical signatures that make artifacts smell distinct.

Pottery-sniffing dogs won’t be showing up at airport customs or on shipping docks soon, but one day, they could be as common as drug-sniffing canines. If dogs can detect low blood sugar or find a tiny USB drive hidden in a house, surely they can figure out if you’re smuggling a sculpture made thousands of years ago in your suitcase.

nextArticle.image_alt|e
iStock
arrow
Animals
15 Confusing Plant and Animal Misnomers
iStock
iStock

People have always given names to the plants and animals around us. But as our study of the natural world has developed, we've realized that many of these names are wildly inaccurate. In fact, they often have less to say about nature than about the people who did the naming. Here’s a batch of these befuddling names.

1. COMMON NIGHTHAWK

There are two problems with this bird’s name. First, the common nighthawk doesn’t fly at night—it’s active at dawn and dusk. Second, it’s not a hawk. Native to North and South America, it belongs to a group of birds with an even stranger name: Goatsuckers. People used to think that these birds flew into barns at night and drank from the teats of goats. (In fact, they eat insects.)

2. IRISH MOSS

It’s not a moss—it’s a red alga that lives along the rocky shores of the northern Atlantic Ocean. Irish moss and other red algae give us carrageenan, a cheap food thickener that you may have eaten in gummy candies, soy milk, ice cream, veggie hot dogs, and more.

3. FISHER-CAT

Native to North America, the fisher-cat isn’t a cat at all: It’s a cousin of the weasel. It also doesn’t fish. Nobody’s sure where the fisher cat’s name came from. One possibility is that early naturalists confused it with the sea mink, a similar-looking creature that was an expert fisher. But the fisher-cat prefers to eat land animals. In fact, it’s one of the few creatures that can tackle a porcupine.

4. AMERICAN BLUE-EYED GRASS

American blue-eyed grass doesn’t have eyes (which is good, because that would be super creepy). Its blue “eyes” are flowers that peek up at you from a meadow. It’s also not a grass—it’s a member of the iris family.

5. MUDPUPPY

The mudpuppy isn’t a cute, fluffy puppy that scampered into some mud. It’s a big, mucus-covered salamander that spends all of its life underwater. (It’s still adorable, though.) The mudpuppy isn’t the only aquatic salamander with a weird name—there are many more, including the greater siren, the Alabama waterdog, and the world’s most metal amphibian, the hellbender.

6. WINGED DRAGONFISH

This weird creature has other fantastic and inaccurate names: brick seamoth, long-tailed dragonfish, and more. It’s really just a cool-looking fish. Found in the waters off of Asia, it has wing-like fins, and spends its time on the muddy seafloor.

7. NAVAL SHIPWORM

The naval shipworm is not a worm. It’s something much, much weirder: a kind of clam with a long, wormlike body that doesn’t fit in its tiny shell. It uses this modified shell to dig into wood, which it eats. The naval shipworm, and other shipworms, burrow through all sorts of submerged wood—including wooden ships.

8. WHIP SPIDERS

These leggy creatures are not spiders; they’re in a separate scientific family. They also don’t whip anything. Whip spiders have two long legs that look whip-like, but that are used as sense organs—sort of like an insect’s antennae. Despite their intimidating appearance, whip spiders are harmless to humans.

9. VELVET ANTS

A photograph of a velvet ant
Craig Pemberton, Wikimedia Commons // CC BY-SA 3.0

There are thousands of species of velvet ants … and all are wasps, not ants. These insects have a fuzzy, velvety look. Don’t pat them, though—velvet ants aren’t aggressive, but the females pack a powerful sting.

10. SLOW WORM

The slow worm is not a worm. It’s a legless reptile that lives in parts of Europe and Asia. Though it looks like a snake, it became legless through a totally separate evolutionary path from the one snakes took. It has many traits in common with lizards, such as eyelids and external ear holes.

11. TRAVELER'S PALM

This beautiful tree from Madagascar has been planted in tropical gardens all around the world. It’s not actually a palm, but belongs to a family that includes the bird of paradise flower. In its native home, the traveler’s palm reproduces with the help of lemurs that guzzle its nectar and spread pollen from tree to tree.

12. VAMPIRE SQUID

Drawing of a vampire squid
Carl Chun, Wikimedia Commons // Public Domain

This deep-sea critter isn’t a squid. It’s the only surviving member of a scientific order that has characteristics of both octopuses and squids. And don’t let the word “vampire” scare you; it only eats bits of falling marine debris (dead stuff, poop, and so on), and it’s only about 11 inches long.

13. MALE FERN & LADY FERN

Early botanists thought that these two ferns belonged to the same species. They figured that the male fern was the male of the species because of its coarse appearance. The lady fern, on the other hand, has lacy fronds and seemed more ladylike. Gender stereotypes aside, male and lady Ferns belong to entirely separate species, and almost all ferns can make both male and female reproductive cells. If ferns start looking manly or womanly to you, maybe you should take a break from botany.

14. TENNESSEE WARBLER

You will never find a single Tennessee warbler nest in Tennessee. This bird breeds mostly in Canada, and spends the winter in Mexico and more southern places. But early ornithologist Alexander Wilson shot one in 1811 in Tennessee during its migration, and the name stuck.

15. CANADA THISTLE

Though it’s found across much of Canada, this spiky plant comes from Europe and Asia. Early European settlers brought Canada thistle seeds to the New World, possibly as accidental hitchhikers in grain shipments. A tough weed, the plant soon spread across the continent, taking root in fields and pushing aside crops. So why does it have this inaccurate name? Americans may have been looking for someone to blame for this plant—so they blamed Canada.

A version of this story originally ran in 2015.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios