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Narwhals and Unicorns

Discussion in 'All Things Boats & Boating' started by kach22i, Dec 16, 2005.

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kach22i Architect

December 13, 2005
It's Sensitive. Really.
By WILLIAM J. BROAD
For centuries, the tusk of the narwhal has fascinated and baffled.

Narwhal tusks, up to nine feet long, were sold as unicorn horns in ages past, often for many times their weight in gold since they were said to possess magic powers. In the 16th century, Queen Elizabeth received a tusk valued at £10,000 - the cost of a castle. Austrian lore holds that Kaiser Karl the Fifth paid off a large national debt with two tusks. In Vienna, the Hapsburgs had one made into a scepter heavy with diamonds, rubies, sapphires and emeralds.

Scientists have long tried to explain why a stocky whale that lives in arctic waters, feeding on cod and other creatures that flourish amid the pack ice, should wield such a long tusk. The theories about how the narwhal uses the tusk have included breaking ice, spearing fish, piercing ships, transmitting sound, shedding excess body heat, poking the seabed for food, wooing females, defending baby narwhals and establishing dominance in social hierarchies.

But a team of scientists from Harvard and the National Institute of Standards and Technology has now made a startling discovery: the tusk, it turns out, forms a sensory organ of exceptional size and sensitivity, making the living appendage one of the planet's most remarkable, and one that in some ways outdoes its own mythology.

The find came when the team turned an electron microscope on the tusk's material and found new subtleties of dental anatomy. The close-ups showed that 10 million nerve endings tunnel from the tusk's core toward its outer surface, communicating with the outside world. The scientists say the nerves can detect subtle changes of temperature, pressure, particle gradients and probably much else, giving the animal unique insights.

"This whale is intent on understanding its environment," said Martin T. Nweeia, the team's leader and a clinical instructor at the Harvard School of Dental Medicine. Contrary to common views, he said, "The tusk is not about guys duking it out with sticks and swords."

Today in San Diego, Dr. Nweeia is presenting the team's findings at the 16th Biennial Conference on the Biology of Marine Mammals, sponsored by the Society for Marine Mammalogy.

James G. Mead, curator of marine mammals at the Smithsonian Institution in Washington, where Dr. Nweeia is a research associate, said the exposed nerve endings appear to be unparalleled in nature.

"As far as I can see, it's a unique thing," Dr. Mead said in an interview. "It's something new. It just goes to show just how little we know about whales and dolphins."

He noted that no theory about the tusk's function ever envisioned its use as a sensory organ.

In the Canadian wilds, the team recently conducted a field study on a captured narwhal, fitting electrodes on its head. Changes in salinity around the animal's tusk, Dr. Nweeia found, produced signs of altered brain waves, giving preliminary support to the sensor hypothesis. The unharmed whale was then released.

With the basics now in hand, the team is working to understand how the narwhal uses the information. One theory is that the tusk can detect salinity gradients that tell if ice is freezing, a hazard that has killed hundreds of narwhals. Tusk readings may also help the whales track environments that favor their preferred foods.

"It's the kind of discovery," said Dr. Mead of the Smithsonian, "that opens up a lot of other questions."

Little about the narwhal's appearance or behavior offers clues to the tusk's sensory importance. The whale has eyes, though small ones. It also has a thick layer of blubber and no dorsal fin so it can swim easily under the ice. Like any whale, it must surface periodically to breathe air. And as in dolphins, its mouth is set in a permanent smile.

The word narwhal (pronounced NAR-wall or NAR-way-l) is said to derive from old Norse for "corpse whale," apparently because the animal's mottled, splotchy coloring recalled the grayish, blotched color of drowned sailors.

Though shy of humans, the animals are quite social. They often travel in groups of 20 or 30 and form herds of up to 1,000 during migrations.

Males weigh up to 1.5 tons, grow about 15 feet long and are conspicuous by their tusks, which can grow from six to nine feet in length. A few females have tusks and, in rare cases, narwhals can wield two of the long teeth. Though often ramrod straight, the tusks always grow in tight spirals that, from the animal's point of view, turn counterclockwise.

The long ivory tusk "looks like a cross between a corkscrew and a jousting lance," Fred Bruemmer, an Arctic explorer, wrote in "The Narwhal" (Swan Hill Press, 1993).

Narwhals live mainly in the icy channels of northern Canada and northwestern Greenland, but they are found eastward as far as Siberia.

The whale's close cousin, the snowy white beluga, thrives in captivity. The shy narwhal tends to die.

Arctic explorers have often observed them at a distance because narwhals frequently raise their heads above the water, their tusks held high. Jens Rosing, in his book "The Unicorn of the Arctic Sea" (Penumbra Press, 1999), tells of seeing them during expeditions off Greenland. There the whales would frolic and apparently mate.

"Over a hundred can be seen at once," he wrote. "They often rise vertically out of the water, lifting themselves with strong movements of their tail fin so that half their body is above water."

Mr. Rosing added: "There is great confusion of movement - both females and males take part. Often one can see a male and female shoot up from the water, trembling, belly to belly."

When luxuriating on their backs in the water, narwhals often turn their heads so their tusks point straight up. Dr. Nweeia of Harvard said the Inuit, the indigenous peoples of the Arctic, who know the narwhal intimately, have a name for the whale that translates as "the one that is good at curving itself to the sky."

Around A.D. 1000, the narwhal tusk debuted in history as a profitable lie. Historians say people in the far north learned of narwhals from Norsemen or perhaps from finding animal bodies occasionally washed up on northern shores. It is known that the Vikings hunted the narwhal and acquired tusks from Arctic natives.

Unscrupulous traders passed them off as one of the most prized objects of all time: unicorn horns.

The ancient Chinese, Greeks, Romans and other peoples had accepted the unicorn as real, and the arrival of the beautifully spiraled objects seemed to prove the animal's existence. The supposed horns sparked huge interest because they were said to have the power to cure ills and neutralize poisons.

Kings and emperors, eager to foil assassins, had cups and eating utensils made of the precious horns. A London doctor advertised a drink made from powdered tusks that could cure scurvy, ulcers, dropsy, gout, consumption, coughs, heart palpitations, fainting, rickets and melancholy.

The horns became an icon of power, both earthly and divine, in part because of their religious associations. In medieval times, the unicorn was seen as a symbol of great purity and of Christ, the motif common in religious art. The fantastic beast appeared in many thousands of images, Mr. Bruemmer wrote, and "All carry a horn that is unmistakably a narwhal tusk, the only long, spiraled horn in all creation."

Churches put small pieces of "unicorn horn" in holy water, giving ailing commoners hope of miracle cures. Meanwhile, the bishops of Vienna carried staffs made of the precious ivory, while St. Mark's Basilica in Venice displayed a horn wreathed in purple velvet.

By the 17th century, the deception began to falter amid the expansion of New World exploration and multiplying reports of bizarre whales that bore long tusks. Ole Wurm, a Danish zoologist, investigated the matter and in 1638 exposed the horn's true origins in a public lecture.

As the unicorn myth died a slow death, the reputation of the narwhal grew larger than life. Explorers claimed its tusk could punch holes in thick ice, and that males battled with their long tusks for supremacy. In 1870, Jules Verne told how a narwhal could pierce ships "clean through as easily as a drill pierces a barrel."

Dr. Nweeia, a general dentist in Sharon, Conn., with an interest in dental anthropology, developed a taste for exotic investigations while doing research on Indian tribes in the Amazon and children in Micronesia. He lectured on how animal and human teeth differ, and eight years ago he began to wonder about narwhals and their odd tusks.

"They defied most of the principles and properties of teeth," he recalled. Many narwhal reports proved contradictory, he found, and "my interest spiraled like the tooth."

In 2000, Dr. Nweeia decided to investigate the animal closely and first trekked to its icy habitat in 2002, going to Pond Inlet, a tiny settlement at the northern tip of Baffin Island. There he met David Angnatsiak, an Inuit guide who agreed to help. Under international agreement, the Inuits are allowed to hunt narwhals, which they eat and harvest for their tusks.

During expeditions in 2003 and 2004, aided by the Canadian Department of Fisheries and Oceans, Dr. Nweeia was able to gather head and tusk specimens, which he brought back for analysis. He and his colleagues tracked a clear nerve connection between the animal's brain and tusk, finding the long tooth heavily innervated. But why it should be so remained a mystery.

The investigators zeroed in on the riddle with sophisticated instruments at the Paffenbarger Research Center of the National Institute of Standards and Technology, a federal organization in Gaithersburg, Md. The American Dental Association finances the research center.

Rough deposits of calcified algae and plankton coated the outside of the tusks Dr. Nweeia brought back. The scientists decided to remove them in an acid bath to get down to the surface of the tooth before viewing it under an electron microscope. First, however, they decided to give the uncleaned tusk a cursory microscopic examination.

It was a shock. There, contrary to all known precepts of tooth anatomy, they found open tubules leading down through the mazelike coating to the tooth's inner nerves and pulp.

"That surprised us," recalled Frederick C. Eichmiller, director of the Paffenbarger Research Center. "Tubules in healthy teeth never go to the surface."

Extrapolating from a count of open tubules over one part of the tooth's surface, the team estimated that the average narwhal tusk had millions of openings that led down to inner nerves.

"No one knew that they were connecting to the outside environment," Dr. Nweeia said. "To find that was extraordinary."

His collaborators include Naomi Eidelman and Anthony A. Giuseppetti of the Paffenbarger Research Center, Yeon-Gil Jung of Changwon National University in South Korea and Yu Zhang of New York University.

Increasingly, the investigation centers on how the whales use their newly observed powers. One central unanswered question is how sensory abilities in males might relate to herd behavior and survival.

The scientists, noting that the males often hold their tusks high in the air, wonder if the long teeth might sometimes serve as sophisticated weather stations, letting the animals sense changes in temperature and barometric pressure that would tell of the arrival of cold fronts and the likelihood that open ice channels might soon freeze up.

Dr. Nweeia noted that the discovery does not eliminate some early theories of the whale's behavior. Tusks acting as sophisticated sensors, he said, may still play a role in mating rituals or determining male hierarchies.

He added that the nerve endings, in addition to other readings, undoubtedly produce tactile sensations when the tusk is rubbed or touched, and that these might be interpreted as pleasurable.

This tactile sense might explain why narwhals engage in what is known as "tusking," where two males gently rub tusks together, Dr. Nweeia said. He added that the Inuit seldom report aggressive contact, undermining ideas of ritualized battle.

Dr. Nweeia said that gentle tusking might also be a way that males remove encrustations on their tusks so tubules stay open, allowing them to better function as sensors. "It may simply be their way of cleaning or brushing teeth," he said.

He called the basic discovery mind boggling, especially given the freezing temperatures of the Arctic.

"This is one of the last places you'd expect to find such a thing," Dr. Nweeia said of the large sensory organs. "Cold is one of the things that tubules are most sensitive to," as people sometimes discover when diseased gums of human teeth expose the tubules.

"Of all the places you'd think you'd want to do the most to insulate yourself from that outside environment," he said, "this guy has gone out of his way to open himself up to it."

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George: Architect (land lover type)
Hovercraft & Vintage Porsche Owner
http://www.boatdesign.net/forums/boat-design/hovercraft-experimental-skirt-project-11973.html

kach22i, Dec 16, 2005

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safewalrus Ancient Marriner

I'm immpressed! What a fantastic article!:!: :!: :!:

safewalrus, Dec 16, 2005

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Bergalia Senior Member

Many thanks Kach22i - this is what makes the forum (apart from SafeWalrus' gibbering) such invaluable reading....

Bergalia, Dec 16, 2005

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safewalrus Ancient Marriner

I thought that's what I said only with a little more enthusiasm, getting so I don't know what I'm sayin' yeah I know.......

safewalrus, Dec 16, 2005

#4

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kach22i Architect

I'm glad you guys liked the article. I picked it up from a guy on a car forum that I've chatted with for a few years, "otto" a wise old man.

If not for the animals of the sea, the sea would just be a bunch of water.

I just came up with that saying, is it catchy?

George: Architect (land lover type)
Hovercraft & Vintage Porsche Owner
http://www.boatdesign.net/forums/boat-design/hovercraft-experimental-skirt-project-11973.html

kach22i, Dec 19, 2005

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kach22i Architect

I'm not sure if this conflicts with the other article at all, or if it is additive.

It turns out that an 8-foot (2.4-meter) tusk, seemingly rigid, can bend 1 foot (30 centimeters) in any direction.

http://news.nationalgeographic.com/news/2005/12/1213_051213_narwhal_tooth.html
A Flexible, 9-Ft. Whale Tooth With Super-Sensing Power?

Pamela Ferdinand
for National Geographic News
December 13, 2005

See photos of narwhals and narwhal tusks >>

For centuries observers have been fascinated and mystified by the majestic spiral tusk grown by the small Arctic whale known as the narwhal.

The extraordinary tooth—extending up to 9 feet (2.7 meters) and textured like a seashell—long evoked the horn of the mythical unicorn and was once sought by royalty as a magical antidote to poison.

Science shed little light on the narwhal tusk, however, and its purpose remained elusive. That is until now.

Martin Nweeia, a Connecticut-based dentist, is expected today to announce two key discoveries that reveal the tusk's unique structure and provide significant clues to its function. The findings may further explain whale species behavior and recast thinking on other mammalian teeth.

Using cutting-edge technology, Nweeia and his colleagues learned that the narwhal's oversize tooth possesses a rare combination of extraordinary strength and extreme flexibility. It turns out that an 8-foot (2.4-meter) tusk, seemingly rigid, can bend 1 foot (30 centimeters) in any direction.

The team also found compelling evidence that the tusk may be a hydrodynamic sensory organ that contains an extensive nerve system and gathers valuable information for survival in Arctic waters.

Researchers say the tusk's nerve system could detect temperature, pressure, motion, and chemical-solution gradients, such as differences in salinity and water particles that would indicate the presence of certain fish prey.

Tactile Tooth

The tusk also may possess tactile abilities, perhaps allowing narwhals to identify and communicate with one another through tapping.

"There isn't any other tooth like this, not even remotely close," said Nweeia, the research team's principal investigator and a Harvard School of Dental Medicine clinical instructor.

The Connecticut-based dentist is scheduled to announce the findings today at the 16th Biennial Conference on the Biology of Marine Mammals in San Diego.

Nweeia, whose latest research was sponsored in part by the National Geographic Society's Expeditions Council, has studied narwhals on four trips to the Canadian high Arctic.

He founded the Narwhal Tooth Expeditions and Research Investigation in 2000, bringing together both scientific experts from a variety of disciplines and members of the region's indigenous Inuit population.

The new findings, which have not been published, are based on analyses of at least six Canadian male narwhal tusks, Nweeia said.

One of a Kind

The narwhal, whose Latin name Monodon Monoceros translates as "one tooth, one horn," typically grows 13 to 15 feet (4 to 4.5 meters) long, not counting its tusk, and weighs about 2,200 to 3,500 pounds (1,000 to 1,600 kilograms).

A protected Arctic species, narwhals are social animals that mostly live in the Atlantic portion of the Arctic Ocean and are found in fewer numbers in the Greenland Sea.

They are hunted by the Inuit for their tusks, meat, and skin. The whales have been known to dive nearly vertically as deep as 3,000 feet (about 900 meters) multiple times per day. (They dive when scared and presumably to feed.)

The mammal's tusk has baffled scientists because it defies known principles and properties of teeth. It is slightly longer than half the animal's length and typically protrudes through the left side of a male's upper jaw plate and lip.

(For comparison, consider a six-foot-tall [two-meter-tall] person with a three-foot-tall [meter-long] incisor jutting straight up into the air.)

Furthermore, unlike the curved teeth of elephants and warthogs, the narwhal tooth is nature's only straight tusk. It consistently spirals on a left-handed, single axis. Scientists speculate the spiral may minimize tusk fractures, and prior research suggests it may aid the tusk's relatively straight growth during development.

Adding to the tusk's uniqueness is its odd gender distribution. The teeth are common in males but not females. Female tusks, when they do appear, tend to be shorter and cleaner with more tightly wound spiral patterns.

Inside Out

The latest findings, researchers say, only add to the narwhal's singularity.

Generally, mammalian teeth are softer on the inside and tougher on the outside to resist wear and abrasion.

But when Naomi Eidelman, an infrared microscopy expert at the Paffenbarger Research Center at the National Institute of Standards and Technology in Gaithersburg, Maryland, used a special technique to map cross-sections of a tusk cell by cell, she reported something dramatically different.

While the tusk contains some materials similar to other mammalian teeth—dentin, pulp, and cementum—it is constructed "inside out," said Frederick Eichmiller, who directs the research center.

A highly mineralized layer surrounds the pulp on the inside, like a steel rod. The outside of the tooth, which resembles enamel at the tip, is actually less mineral and more protein.

Cementum is usually the layer that bonds the tooth to the bone in other mammalian teeth. But in this case, the cementum is "just sticking out into the ocean," Eichmiller said. "This tooth was different from what we've seen before," he said. "Ever."

Scientists theorize the reverse architecture endows the tusk with flexibility, possibly helping it to absorb shock and resist extreme water pressures during deep dives.

The tusk does not appear able to lay down another form of dentin to heal cracks, and perhaps it does not need to, Nweeia says. The researcher adds that the tusk's unusual qualities could have profound implications for modern dentistry and biomaterials science.

"Everything about this tusk is built not to break," he said. "To find a material that is flexible and strong—that is kind of the grail for restorative materials. This guy's got it."

Sensing the Environment

The new findings also provide significant clues to tusk function, a puzzle that has generated conflicting theories, from displaying aggression to breaking ice.

Using scanning electron microscopy, researchers uncovered evidence of dentinal tubules, basic structures that exist in almost all teeth, including humans. The tubules are remnants of a cell process in which millions of tiny nerve connections tunnel their way from the central nerve of a tooth to its outer surface.

Tubules in human mouths are sensitive to cold and are normally covered by enamel. We experience discomfort and pain only when they are inadvertently exposed, through cavities, for example.

Narwhal tubules, however, penetrate the outermost layer of the tooth, directly exposing sensory connections to the Arctic environment. The result is that the tusk—despite its inanimate appearance—actually serves as a kind of membrane with an extremely sensitive surface, researchers say.

Tubules are known to allow for specific sensory functions in mammals, such as gauging air temperature and barometric pressure. But it remains to be seen what they are used for by the narwhal, whose tubules contain a solution similar to blood plasma, Nweeia says.

Sensing salinity is one possible answer; Nweeia and his colleagues have developed customized equipment to test this theory that measures narwhal brain activity when saline solution is introduced to the tusk.

Narwhal migration is tied to ice formation, which affects saline concentrations, and narwhals may be able to detect subtle changes in the environment from miles away, Nweeia said.

Human teeth have evolved so that "we go out of our way not to have cold things against a tubule," he said. "Why does an Arctic whale, who is in frigid waters and incredible pressures all of his life, go out of his way to have open tubules?"

"If you are going to develop something like this, from an evolutionary standpoint it has to be about survival. There are a lot better ways to get a female than growing one of these," he added.

Solving the Puzzle

Future field expeditions are expected to focus on anatomical studies and sensory research.

Scientists at Johns Hopkins University in Baltimore, Maryland, are conducting CT and MRI scans on two narwhal heads, one male and one female. And a dissection team, led by James Mead of the Smithsonian Institution, will convene in January.

Still unanswered, researchers say, are fundamental questions about how and why the tusk evolved.

"There's a difference, but why is there a difference?" Eichmiller said. "That's the part that is the most intriguing."

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George: Architect (land lover type)
Hovercraft & Vintage Porsche Owner
http://www.boatdesign.net/forums/boat-design/hovercraft-experimental-skirt-project-11973.html

kach22i, Dec 19, 2005

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safewalrus Ancient Marriner

Yeah it's catchy, dunno about the the 'bunch' tho, needs refining - then you got yourself a catchphrase. As for the rest WOW

safewalrus, Dec 19, 2005

#7

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kach22i Architect

The researcher adds that the tusk's unusual qualities could have profound implications for modern dentistry and biomaterials science.

Every time I skim it, I catch another profound item.

There are a lot better ways to get a female than growing one of these," he added.

Is he speaking from experience?

George: Architect (land lover type)
Hovercraft & Vintage Porsche Owner
http://www.boatdesign.net/forums/boat-design/hovercraft-experimental-skirt-project-11973.html

kach22i, Dec 19, 2005

#8

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artemis Steamboater

kach22i said:

There are a lot better ways to get a female than growing one of these," he added.

Is he speaking from experience?
Click to expand...

No, NO, NO! kach22i. You have opened up this posting to comments by Bergalia and other Scots/Welsh/Cornish males about the efficacy of their reproductive organs. Someone will then probably ask for a poll about posting of "sexually explicit/implicit opinions". Arrrrrrrrgh! Please remove your posting ASAP before one of the above mentioned sees it.

artemis, Dec 19, 2005

#9

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safewalrus Ancient Marriner

Artemis

Too late buddy it's been spotted! If it wasn't such a good article we'd be homing in on it already but being nice guys - like wot we is we'll leave it until after Christmas, then!.......

safewalrus, Dec 20, 2005

#10

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boltonprofiles Senior Member

kach22i - Great, very interesting, thanks.
Walrus, Max, don't care what the subjects are as long as its not blooming string!!!!!!!!

--- Paul ---
Northwest Metal Profiling Limited
Web site - http://www.nwmpltd.com
""When quality matters""

boltonprofiles, Dec 23, 2005

#11

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safewalrus Ancient Marriner

Hey Paul what's wrong with string? it's bloody useful stuff!

safewalrus, Dec 23, 2005

#12

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Bergalia Senior Member

safewalrus said:

Hey Paul what's wrong with string? it's bloody useful stuff!
Click to expand...

And I'm getting some more for Christmas....

As a slight aside...My silence (blessed or otherwise) over the past few days is not due to a case of umbrage... merely a lightning strike which cooked my modem (along with half a dozen others on the NSW coast). Luckily I've access to the studio machine (a bloody PC - but at least it serves) so in between wowing radio listeners with my wit and wisdom I can reassure the forum that I'm not yet sunk.
Anway - all of you have a great and safe Christmas, and a properous New Year. Meanwhile, the ship is yours...I'm going ashore (temporarily).
Yours aye, Max (aka Bergalia)

Bergalia, Dec 23, 2005

#13

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safewalrus Ancient Marriner

Aye Cap'n

Leave to the bloody mate again (just knew I shoulda taken the driver's job when offered!) have a good one Bergalia, and the rest of ye to!

safewalrus, Dec 24, 2005

#14

Filmdaddy Previous Member

The erudition on this board is astonishing.

Filmdaddy, Dec 29, 2005

#15

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