The narwhal: a serious case of nerves

"Narwhal or unicorn"

Timeline, 2006: The narwhal has a history as striking as the animal itself. Vikings kept the narwhal a secret for centuries even as they peddled its “horn” as that of a unicorn. Narwhal tusks were so prized that monarchs paid the equivalent of the cost of a castle just to have one. They were thought to have magic powers, render poison ineffective, cure all manner of diseases, and foil assassins.

A tooth and nothing but a tooth

As it turns out, the horn is really just a tooth, an extremely long, odd, tooth. The narwhal tusk, which usually grows only on males from their left upper jaw, can reach lengths of six feet or more. Sometimes, males will grow two tusks, one on each side. The tooth turns like a corkscrew as it grows, stick straight, from the narwhal’s head. They are such an odd sight that scientists have been trying to figure out for centuries exactly what that tusk might be doing there.

Some have posited that the narwhal uses the tusks in epic battles with other male narwhals. Others have fancifully suggested that the animal might use the long tooth to break through the ice, ram the sides of ships (nevermind the disconnect between when the tusk arose and when ships entered the scene), or to skewer prey—although no one seems to have addressed how the narwhal would then get the prey to its mouth.

Gentle tusk rubbing

The facts are that the narwhal rarely, if ever, appears to duel with other narwhals. Its primary use of the tusk appears to be for tusking other males, in which the animals gently rub tusks with one another. They also may be used in mating or other activities, although that has not yet been demonstrated. But what has been discovered is that the narwhal ought to be suffering from a severe case of permanent toothache.

Arctic cold strikes a narwhal nerve

Anyone who has ever had exposed nerves around their teeth knows that when cold hits those nerves, the pain usually sends us running for the dentist. Now imagine that your tooth is six feet long, has millions of completely exposed nerve endings, and is constantly plunged in the icy waters of the Arctic. You’ve just imagined being a narwhal.

Dentist on ice

A clinical instructor at the Harvard School of Dental Medicine who thinks of nothing but teeth made this discovery about the narwhal. The instructor, Martin Nweeia, can wax rhapsodic about teeth and how central they are to our health and the stories they can tell even about how we lived and died. He has carried his tooth obsession beyond his own species, however; his passion led him to spend days on Arctic ice floes, watching for the elusive narwhal, or at least one of the tusks, to emerge from the deadly cold water. He also befriended the local Inuit, who rely on the narwhal as a source of food and fuel oil.

His fascination and rapport with the Inuit people ended with his viewing several specimens of narwhal tusks. What he and his colleagues discovered astonished them. The tusks appeared to consist of open tubules that led straight to what appear to be millions of exposed nerve endings. In humans, nerve tubules are never open in healthy teeth. But in the narwhal tusk, which is an incredible example of sexual dimorphism and the only spiral tooth known in nature today, these open tubules were the norm.

Sensory tooth

The researchers speculated that the animals may use this enormous number of naked nerves as a finely sensitive sensory organ. In addition, it is possible that the teeth transmit voltage through a process called the piezo effect, in which crystals generate voltage when a mechanical force rattles them. In the case of the narwhal, who swim quickly through the water, water pressure might provide the force. Because narwhals are among the most vocal of whales, the tusks could also be sound sensors.

Why would dentists be so interested in the tusks of a whale? Examinations of the narwhal tusks have revealed that they are incredibly flexible, unlike our teeth, which are strong but also rigid and comparatively brittle. It is possible that understanding the narwhal tusk might have clinical applications for developing flexible dental materials for restoring pearly whites in people.

Beethoven died of lead poisoning–or did he?

Did lead kill Beethoven?

Timeline, 2005 and 2010: Literary folk have often noted the passion and emotion of Ludwig van Beethoven’s works. Lucy Honeychurch, the heroine of E.M. Forster’s A Room with a View, became “peevish” after playing Beethoven, and of course there’s the famous hooligan Alex from A Clockwork Orange, who was roused to stunning displays of violence after hearing “Ludwig van.” Given Beethoven’s own behavior, which was punctuated by violent rages, frequent sudden outbursts, and wandering the streets humming loudly, it’s not surprising that his music would communicate his passion.

A heavy metal influence?

A study in 2005 (news release here) yielded results that suggested that much of his anger, however, was attributable to the effects of heavy metal…specifically, lead. Beethoven became sick in his 20s (he also went deaf in his 20s), and suffered until his death at the age of 56 from a variety of illnesses, including chronic diarrhea and other stomach ailments. His death was lingering and painful, and some people thought that he had suffered from syphilis. Yet now many of his symptoms fit the classic description of slow lead poisoning. Among the effects of lead poisoning are irritability, aggressive behavior, headaches, and abdominal pain and cramping, all of which Beethoven experienced.

Doctor to businessmen to Sotheby’s to science

Some samples of the great composer’s hair and skull are available today for sophisticated testing for metals. A Viennese doctor apparently snagged a few fragments of his skull 142 years ago and the pieces eventually made their way through the family to a California businessman. The hairs were cut by a student soon after Beethoven died and ended up at a Sotheby’s auction. A few years ago, tests on the hairs suggested that Beethoven’s body harbored high levels of lead—hair accumulates and retains such toxins better than any other tissue—but because the testing method destroyed the hair, further tests were not completed.

Wobbling electrons solve the mystery?

Since that time, a powerful new X-ray technique has become available. The Department of Energy’s Argonne National Laboratory owns the X-ray. In the facility, subatomic particles fly through a tubular tunnel almost at the speed of light, emitting as they travel X-rays 100 times brighter than the sun’s surface. These X-rays can bounce off of the surface of even a tiny sample. As they bounce off of the sample, electrons wobble out of place, releasing energy in a pattern that is specific to the atom being bombarded.

Researchers were interested in Beethoven’s hair and skull pieces. The team that evaluated the samples actually works on developing bacteria that can take up heavy metals and render them relatively harmless; such organisms would be useful in environmental detoxification. They placed Beethoven’s hair in their high-powered X-ray. The electrons wobbled and the pattern indicated that Beethoven was simply full of lead. In fact, they reported that the poor man had about 60 parts per million of lead in his body, which is 100 times normal levels. It certainly was enough to make a person manifest the various symptoms that characterized most of Beethoven’s life.

The team also looked for a pattern that arsenic would emit, and they found none. This result seemed to exonerate Beethoven from having had syphilis, since arsenic would have been the treatment of choice for such an ailment.

Not so fast

At the time the study results were revealed, ideas about how did Beethoven built up so much lead abounded. Some suggested that  his body was less able than normal to rid itself of the heavy metal, through which he’d have been exposed by many channels. His stomach problems and temperament led him to consume much wine, and the vessels for drinking wine contained lead. In addition, his medicines probably were stored in lead-lined bottles or vials, and he may well have visited spas—for his health, ironically—at which he consumed or swam in mineral water containing lead. In one report, Beethoven’s poor doctor was identified as the likely culprit in his demise.

Fast-forward five years to 2010. A deeper analysis (news release here) of the bone fragments from Beethoven’s school indicated that his lead levels were not that spectacular. The bone is the reservoir for most of the lead the body takes up, and Beethoven’s bones simply didn’t have enough to have caused his various physical ailments. While the experts seemed to be in agreement that the results point away from lead, a new heavy metal mystery arose from the results. One skull fragment they tested had about 13 mcg of lead per gram of bone, nothing to write home about, while another sample turned up with 48 micrograms per gram, a much higher level. Nevertheless, we must look elsewhere for what killed one of the world’s greatest western composers. Ideas being tossed around include lupus and heart disease. What we do know is that he lived in terrible pain, both from his maladies and from the treatments designed to help, including pouring hot oil in his ears, according to one Beethoven scholar quoted in the New York Times.

Another wrongly accused suspect

Heavy metals have featured in other historical whodunits. For example, Napoleon reportedly died of stomach cancer during his exile on Elba, but one analysis showed that he actually died of slow arsenic poisoning, suggested to have been at the hand of his closest assistant. Then, much like Beethoven’s story, a later study showed that arsenic likely played no role in the great general’s death.

Columbus Day post: Failed Columbus settlement found no silver

Christopher Columbus

Columbus may have made his name for the history books by “finding” the Americas, but his real claim to fame may have been his world-class snake oil salesman ability. After returning from his famed voyage of 1492, Columbus bowed before his patrons, Spain’s King Ferdinand and Queen Isabella, and spun a tale of precious metals in the new world. His fairy stories about a land of silver and gold lit a fire under the Spanish royals, leading them to finance a much larger second expedition to the New World Columbus had stumbled on.

Tall tales of silver and gold

His tall tales also attracted a huge crowd of settlers with gold in their eyes and riches on the brain. This hapless group, 1500 strong, landed on the north shore of today’s Dominican Republic in 1494, only to find a land of sand and hardship, not the streets of gold they’d expected. Catastrophe piled on top of catastrophe in the form of hunger, disease, hurricanes, and conflicts with the indigenous people. Mutiny not unnaturally followed, and four years after the settlement was established, the few hundred remaining settlers abandoned the effort and returned home.

This failed first European town in the New World left behind a treasure trove for archaeologists, however. Among the finds was about 100 pounds of galena, a lead ore containing silver. Medieval people used galena to determine how much silver a substance contained. They could create galena with a known amount of silver, or galena could be found and its silver content compared with galena containing the known amount of ore.

Why is all this galena lying around?

For many years, scholars had thought that the galena found at the settlement, which its founders had called La Isabela after the financier queen, was the result of the settlers’ discovery of silver in the area. The odd thing was, no settler ever left a written record of such a discovery. Given the 100 pounds of it and the detailed records people on such expeditions tended to leave, such a find usually would have earned a mention.

In addition to the pounds of galena, researchers also found several hundred pounds of slag, which turned out to be lead silicate with flecks of silver in it. This slag also could have been the result of settlers’ attempts to extract silver from a local discovery. But again, there was no mention in the record of what would have been a significant operation, given the 400-plus pounds of slag. The galena and slag were discovered near a building that was used to store royal property.

Starving and desperate for silver

To address the discrepancy between the written record and archeological inference, a group of researchers applied chemical analysis to the galena and slag and compared it to known samples of Caribbean ores. They found that the galena and slag did not come from a Caribbean location and instead probably traveled with the settlers from Spain. The researchers speculate that the settlers, starving and desperate, were frantically trying to extract silver from items in the royal coffers.

Supporting this idea is the fact that the lead in the galena would normally have been more useful to them, for things like musket balls or supports for a ship. The waste, in the form of the lead silicate slag, was of no use to them at all.

An expert in medieval chemistry told the researchers that people of that era commonly mixed galena with ores they thought might contained a precious metal, using galena with a known quantity as a marker for how much gold or silver their discovered ore contained. This explanation may provide the reason the settler had galena with them in the first place.

Batty bigamy and worse

Normally, inbreeding isn’t such a good thing

The idea that three generations of related females might share the same mate is, frankly, abhorrent and strange to us humans, but among bats, this tactic may be a fairly common phenomenon.

Generally, animals avoid inbreeding with one another because doing so results in the development of “inbreeding depression” in a population. This depression refers to falling rates of reproduction and survival that result when relatives interbreed. An example of what happens with inbreeding can be found among the royal houses of Europe in previous centuries. The members of these families would often receive papal dispensations to ignore the rules about consanguinity—close relatedness—to be allowed to marry another royal personage. There just weren’t that many eligible royal folk wandering around Europe and inbreeding was the ultimate result.

Hidden disorders emerge

Because of this inbreeding, often with third or second cousins marrying through several generations, the royal families would manifest disorders that normally would remain hidden. Some of these disorders required the inheritance of two alleles, both carrying mutations, for them to manifest. If the royal families had not constantly been intermarrying, the two recessive alleles would have been much less likely to come together in a single person. As it was, many royal households had children who were sickly, who could not reproduce successfully, or who manifested mental illness or retardation. One particularly notable trait that arose through several families was the “Hapsburg jaw,” a severe underbite and jutting jawbone that traced its way through the European royal chessboard. One potentate had a jaw deformity so severe that he could not chew his food.

Horseshoe bats don’t care

But the greater horseshoe bat appears to be untroubled by such issues of consanguinity, at least in the sense that related females from several generations will mate with the same male. In the world of the horseshoe bat, it pays to be a male bat who attracts a female. If the male attracts the daughter, he has a good chance of also mating with the mother and the grandmother, too. And he may be set for his relatively long bat-life; greater horseshoe bats can live up to 30 years, and females will consistently select the same male for the annual bat mating ritual, which results in a single offspring per female each year.

In spite of this inbreeding and polygyny, in which several females mate with the same male, the females apparently are quite adept at avoiding mating with their own fathers. A female will only mate with her mother’s partner if her mother has switched partners and is no longer mating with the daughter’s father.

Beat that, Belgium

This complex mating web results in a bat family tree that is more confusing than that of all the royal houses of Europe combined. It is possible for a female bat and her maternal half-aunt to be half-sisters on their father’s side.

How did researchers unravel this remarkable complexity? They identified a colony of female bats—who spend most of the year living in single-sex groups—in an old mansion in Great Britain. DNA analysis showed that the several hundred females lived in about 20 groups of related females who shared mates. The females met up with the males, who lived in a permanent stag party condition in a nearby cave, only once a year. Researchers speculate that females use smell to avoid mating with their fathers.

What benefit this interbreeding?

Why risk interbreeding in the first place? Actually, many species exhibit tactics that lead to closer kinship among individuals. Researchers speculate that closer kinships result in better teamwork to protect the genetic investment. In the world of team-playing ants, for example, female siblings can be 75% related, rather than the 50% most sexually producing species share genetically with their siblings. Experts believe that this extra genetic relatedness enhances the teamwork atmosphere of an ant colony. In much the same way, the related groups of female bats work together to raise the young. Researchers believe that this horseshoe bat tactic may extend beyond the greater horseshoe to other bat species.

Africa ahead of Europe in civilization?

Seashells with holes and a smudge

A handful of small seashells with holes and a smudge of red have muddied the waters of human history yet again. Previously, researchers found some seashell beads very much like these in South Africa, beads obviously used for adornment and made about 75,000 years ago. The latest find, shells of the mollusk Nassarius gibbosulus, date back even further, to about 82,000 years ago, making them among the oldest examples of human civilization.

Much to the chagrin of experts who have argued that such artistic endeavors arose in Europe and the Middle East around 40,000 years ago, these beads—clear evidence of what the news media are calling the earliest “bling”—were found in Morocco, in northern Africa. Their strong similarity to the shell beads from South Africa suggest a free exchange of culture and symbolism. In fact, there are only two kinds of shell from this period that have been found in Africa and the Near East, although the people living in these areas had many more choices. This selection of such similar shells also signals a universally understood symbolism involving these beads.

A record competition

The truly oldest beads found so far were from Israel. They were two little beads dating back as far as 100,000 years, although the dating on these is iffy because they were found in the 1930s. Today’s dating methods are much more precise; in fact, the researchers who discovered the 13 Moroccan beads applied four different approaches to dating them, all of which agreed on their age.

The beads were found in the strangely named Cave of Pigeons (Grotte des Pigeons) in Taforalt, Morocco. Around the beads, the researchers also found stone tools and the remains of animals. They concluded that the tools, which were sharp, pointed rocks, were probably spearheads used for hunting. The animal bones, primarily from wild horses and rabbits, had simply been the remains of dinner.

Humans, artistic humans

Each of the small shells, no bigger than a thumbnail, had been perforated deliberately. Some showed signs of wear, as though they had been strung or beaded onto clothing or as a bracelet or necklace for regular use. And the shells bore the traces of red ocher, a pigment that also features in the beads identified in South Africa.

The researchers who found the beads weren’t actually looking for an earth-shattering archaeological find. Their true goal in investigating the limestone cave was to glean information about how climate change might have affected ancient humans. Instead, they found these shells, obviously transported to this inland cave, which at the time the beads were made was about 25 miles from the sea. The people who made them had the self-awareness necessary to desire adornment, and they also had an understanding of objects as symbols, rather than simply as the objects they actually are. In this case, the shells could have symbolized beauty or fashion, or even some form of currency.

Africa moves ahead of Europe

These finds are a blow to those who maintain that humans didn’t achieve any form of cultural modernity until they were in Europe around 35,000 years ago. No one has found items of such ancient origin in European sites. Thus, it seems that humans in Europe, rather than being ahead of their African peers, were actually lagging behind. The north and south Africans were apparently exchanging bead fashion tips tens of thousands of years before the shells were anything but, well, shells to humans in Europe.

The researchers couldn’t just find the beads and date them and then call it done. They had to prove that the snail shells had gotten to the site by human interference. To demonstrate this, the scientists had to rule out the presence of these animals in the walls of the cave, or that the shells were transported by a predator.

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