Untangling the Secrets of Sea Silk, the Ancient Mediterranean’s Elusive Luxury Textile

In the famous Greek myth, the hero Jason and his band of Argonauts seek a precious fleece, allegedly woven from the wool of a golden ram, to exchange for the throne of Thessaly. Around the same era, stories told of the biblical King Solomon describe him wearing a lightweight tunic that shimmered when he stepped into the sunlight. The New Testament repeatedly describes angels as being clothed in "pure and shining linen,” and the apostle Luke as wearing “shining garments.” But was this all just metaphorical holy light—or something real and reproducible? 

As far as anyone knows, there's never been a sheep whose wool gleamed golden. However, many theories have been concocted to explain the existence of a sparkling gold fabric long before the invention of lamé. It’s just a symbol, most say—of wealth, kingship, authority, and so on. 

But these stories also share a possible interpretation that’s based in reality: They may be referring to byssus.

Also known as sea silk, byssus is an ancient textile woven from the beard of various clams, and which appears dark brown until placed under direct light, when it glitters like gold. Although it can be made from a few different mollusks, the beard of the noble pen shell, Pinna nobilis, has historically been the preferred source. Pen shells are quite large as clams go, growing up to 4 feet in length, and produce thin but very strong filaments—solidified saliva, really—that anchor the mollusks to the floor of the sea. With strands about half the circumference of a human hair, the silken beard of P. nobilis is ideal for weaving, as it's far less coarse than that of its cousins in the pinnidae family. 

The threads of the fabric’s history are difficult to trace, beginning with the fact that the word byssus itself once referred to any precious textile. The Old Testament reportedly includes 45 mentions, but some of them, judging from the context, almost certainly refer to linen, cotton, or regular silk. The same is true for the cloth that Egyptians used to wrap mummies, which scholars have translated as “byssus." But it’s hard to be sure which byssus they’re talking about: sea silk, or another precious textile? The silken filaments that compose the pen shell’s beard are also called byssus, adding to the confusion.

And fictions have thrived around byssus: In 945, the Book of Tang (Tángshū), a historical work about the imperial Tang dynasty of China, described a golden textile called byssus as being woven “from the hair of the sea-sheep,” whatever that might have been. Estakhri, a 9th-century Persian geographer, writes similarly of an animal that runs into the sea and rubs itself against certain stones, whereupon it produces "a kind of wool of silken hue and golden color."

Much later, Jules Verne spoke of it in Twenty Thousand Leagues Under the Sea. In the original French version, he describes the crew of the Nautilus being dressed in byssus and detailed its aquatic origins. However, “byssus” was called “seashell tissue" or "fan mussel fabric" in English translations, which caused some readers to believe the material was dreamt up expressly for science fiction. 

The real, clam-made byssus was highly prized by the ancient Greeks and Mesopotamians, among other cultures, for not only its glittery, color-shifting properties but also for its combination of daintiness and warmth. Stockings and gloves were popular uses for sea silk; a pair of byssus gloves were reported to be so extraordinarily light they would fit folded inside of a walnut's shell, and a pair of stockings inside a snuff box. 

Women spinning bysso, from a display in Sardinia. Image credit: Sicco2007, Flickr // CC BY-NC-ND 2.0

Byssus fell out of fashion for a few centuries, although it enjoyed a short renaissance in the 1800s among the wealthy. But aside from museum and gallery collections exhibiting vintage pieces, it’s nearly nonexistent today, and for good reason. P. nobilis is currently endangered—a victim of not just overfishing and trawling in the Mediterranean but also of pollution, to which it's highly susceptible. These factors make the harvesting of the byssus all the more difficult—and the cloth itself perhaps even more expensive than it was in ancient times.

However, Italian weaver Chiara Vigo, who says she has developed a method of harvesting the silken fibers from the pen shell without killing the creature, has been granted special clearance to dive for them in her hometown of Sant'Antioco, Sardinia, while accompanied by members of the Italian Coast Guard. Vigo’s family has been weaving byssus for centuries. She learned the trade from her grandmother—although it should perhaps be called a “trade” only loosely, since she's sworn to never sell the cloth (further adding to its scarcity). Vigo believes the cloth is sacred, calling it “the soul of the sea,” and claims to have never earned a cent (or lira) from her skill.

As the BBC notes, Vigo also believes that a gift of byssus brings good fortune to families, so she provides her service to those who appear at her studio in person. She gives byssus-embroidered christening dresses to babies, byssus bracelets to pregnant women (or those who aspire to be), and byssus rings to little girls (to bring back to Vigo when they're grown and engaged, whereupon she’ll make them a byssus doily for their marriage bed).

Rumor has it that a few elderly women on the Italian mainland still know how to weave byssus, but Vigo is the only known living master. She’s only person who can make it shine, using a special solution, and who can dye it in the traditional way. She’s also said to be the only person who is legally cleared to harvest it. And Vigo holds a secret, to boot: She’s one of the few living people who know where exactly the field of pen shells is located in the waters surrounding Sant’Antioco.

Whatever the truth behind byssus’s complicated backstory, the good news is that for now, sea silk is still quietly being woven in an ancient village on a tiny island just off of a larger island in the Mediterranean—and that Chiara Vigo is willing to share her knowledge. In addition to spending a few hours in the evenings teaching students how to weave byssus, she has also taught her daughter the craft, vowing that she’ll one day take over the family tradition. Hopefully, in an era where glitter is everywhere but traditional materials are scarce, the fabric will continue to survive, and as more than a myth. 

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Big Questions
Why Don't We Eat Turkey Tails?
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Turkey sandwiches. Turkey soup. Roasted turkey. This year, Americans will consume roughly 245 million birds, with 46 million being prepared and presented on Thanksgiving. What we don’t eat will be repurposed into leftovers.

But there’s one part of the turkey that virtually no family will have on their table: the tail.

Despite our country’s obsession with fattening, dissecting, and searing turkeys, we almost inevitably pass up the fat-infused rear portion. According to Michael Carolan, professor of sociology and associate dean for research at the College for Liberal Arts at Colorado State University, that may have something to do with how Americans have traditionally perceived turkeys. Consumption was rare prior to World War II. When the birds were readily available, there was no demand for the tail because it had never been offered in the first place.

"Tails did and do not fit into what has become our culinary fascination with white meat," Carolan tells Mental Floss. "But also from a marketing [and] processor standpoint, if the consumer was just going to throw the tail away, or will not miss it if it was omitted, [suppliers] saw an opportunity to make additional money."

Indeed, the fact that Americans didn't have a taste for tail didn't prevent the poultry industry from moving on. Tails were being routed to Pacific Island consumers in the 1950s. Rich in protein and fat—a turkey tail is really a gland that produces oil used for grooming—suppliers were able to make use of the unwanted portion. And once consumers were exposed to it, they couldn't get enough.

“By 2007,” according to Carolan, “the average Samoan was consuming more than 44 pounds of turkey tails every year.” Perhaps not coincidentally, Samoans also have alarmingly high obesity rates of 75 percent. In an effort to stave off contributing factors, importing tails to the Islands was banned from 2007 until 2013, when it was argued that doing so violated World Trade Organization rules.

With tradition going hand-in-hand with commerce, poultry suppliers don’t really have a reason to try and change domestic consumer appetites for the tails. In preparing his research into the missing treat, Carolan says he had to search high and low before finally finding a source of tails at a Whole Foods that was about to discard them. "[You] can't expect the food to be accepted if people can't even find the piece!"

Unless the meat industry mounts a major campaign to shift American tastes, Thanksgiving will once again be filled with turkeys missing one of their juicier body parts.

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10 Juicy Facts About Sea Apples

They're both gorgeous and grotesque. Sea apples, a type of marine invertebrate, have dazzling purple, yellow, and blue color schemes streaking across their bodies. But some of their habits are rather R-rated. Here’s what you should know about these weird little creatures.


The world’s oceans are home to more than 1200 species of sea cucumber. Like sand dollars and starfish, sea cucumbers are echinoderms: brainless, spineless marine animals with skin-covered shells and a complex network of internal hydraulics that enables them to get around. Sea cucumbers can thrive in a range of oceanic habitats, from Arctic depths to tropical reefs. They're a fascinating group with colorful popular names, like the “burnt hot dog sea cucumber” (Holothuria edulis) and the sea pig (Scotoplanes globosa), a scavenger that’s been described as a “living vacuum cleaner.”


Sea apples have oval-shaped bodies and belong to the genus Pseudocolochirus and genus Paracacumaria. The animals are indigenous to the western Pacific, where they can be found shuffling across the ocean floor in shallow, coastal waters. Many different types are kept in captivity, but two species, Pseudocolochirus violaceus and Pseudocolochirus axiologus, have proven especially popular with aquarium hobbyists. Both species reside along the coastlines of Australia and Southeast Asia.


Sea cucumbers, the ocean's sanitation crew, eat by swallowing plankton, algae, and sandy detritus at one end of their bodies and then expelling clean, fresh sand out their other end. Sea apples use a different technique. A ring of mucus-covered tentacles around a sea apple's mouth snares floating bits of food, popping each bit into its mouth one at a time. In the process, the tentacles are covered with a fresh coat of sticky mucus, and the whole cycle repeats.


Sea apples' waving appendages can look delicious to predatory fish, so the echinoderms minimize the risk of attracting unwanted attention by doing most of their feeding at night. When those tentacles aren’t in use, they’re retracted into the body.


The rows of yellow protuberances running along the sides of this specimen are its feet. They allow sea apples to latch onto rocks and other hard surfaces while feeding. And if one of these feet gets severed, it can grow back.


Sea apples are poisonous, but a few marine freeloaders capitalize on this very quality. Some small fish have evolved to live inside the invertebrates' digestive tracts, mooching off the sea apples' meals and using their bodies for shelter. In a gross twist of evolution, fish gain entry through the back door, an orifice called the cloaca. In addition expelling waste, the cloaca absorbs fresh oxygen, meaning that sea apples/cucumbers essentially breathe through their anuses.


Most full-grown adult sea apples are around 3 to 8 inches long, but they can make themselves look twice as big if they need to escape a threat. By pulling extra water into their bodies, some can grow to the size of a volleyball, according to Advanced Aquarist. After puffing up, they can float on the current and away from danger. Some aquarists might mistake the robust display as a sign of optimum health, but it's usually a reaction to stress.


Sea apples use their vibrant appearance to broadcast that they’re packing a dangerous toxin. But to really scare off predators, they puke up some of their own innards. When an attacker gets too close, sea apples can expel various organs through their orifices, and some simultaneously unleash a cloud of the poison holothurin. In an aquarium, the holothurin doesn’t disperse as widely as it would in the sea, and it's been known to wipe out entire fish tanks.


These invertebrates reproduce sexually; females release eggs that are later fertilized by clouds of sperm emitted by the males. As many saltwater aquarium keepers know all too well, sea apple eggs are not suitable fish snacks—because they’re poisonous. Scientists have observed that, in Pseudocolochirus violaceus at least, the eggs develop into small, barrel-shaped larvae within two weeks of fertilization.


Syzgium grande is a coastal tree native to Southeast Asia whose informal name is "sea apple." When fully grown, they can stand more than 140 feet tall. Once a year, it produces attractive clusters of fuzzy white flowers and round green fruits, perhaps prompting its comparison to an apple tree.


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