About Muscle and Bone

Last October I blogged about Halloween costumes and the importance of being anatomically correct when stepping out as a skeleton.  I am sure that bone lovers everywhere are equally tetchy about other anatomically incorrect Halloween accoutrements, because if the manufacturer has taken liberties with anatomical accuracy, we would have to question both their world view and commitment to all-around quality.

Let’s start with a biology refresher. Worms, obviously, do not have bones, but neither do some critters that crunch when stepped on. For instance, insects, spiders, and crustaceans (lobsters, shrimp, etc.) have exoskeletons made from thin, waterproof, semirigid shells of chitin. This certainly is a successful means of protection and support, but it presents a problem when the owners want to expand, They have to crawl out of their skeletons and grow a new ones. In the interim, they are vulnerable to predation and may turn into soft-shelled crab sandwiches. Clams, snails, scallops, and oysters avoid this perilous transition by merely making regular additions to the edges of their calcium-based exoskeletons and gradually enlarge them without having to leave home.  

Animals with spines (vertebrates) have endoskeletons. For sharks, that means rubbery cartilage (the same material that constitute our noses and external ears). Bony fish, and amphibians (frogs, salamanders, etc.), reptiles including birds, and mammals (including us) have skeletons made of rigid, calcium-laden bone. Its durability allows bone to preserve evidence of formerly living animals, which is integral to the concept of Halloween.

After this brief biology overview, you can probably spot what is wrong in these pictures.

Look at the ears on the dog and horse. They are as out of place on a skeleton as a stocking cap or moustache would be. Worse, however, are the lobster and spider. My spine shudders to see them represented with bony endoskeletons rather than with their naturally occurring chitin armor.

On viewing the original version of this post earlier today, sharp-eyed bone lovers also identified several disturbing errors in skeletal anatomy on the human in the foreground. The lower legs are on the wrong side. (The thicker bone, the tibia, should be on the inside of the thinner bone, the fibula, on the outside.) The right hip is dislocated, which may account for the pained expression on the skeleton’s face. It looks like there are eight sets of ribs rather than twelve. At least the human skeleton is not sporting bone ears as do the horse and dog.

As you come across Halloween decor this week, please document other bone infractions and send photos to info@aboutbone.com.  I will notify the Bone Police immediately. I know, it’s frightful, but then, that’s what Halloween is about.

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And if you find Halloween’s disrespect of bones irksome, it gets worse. Watch for A Bone Lover’s Thanksgiving Nightmare, coming soon.

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For Halloween and all other special occasions, no gift is in finer taste or will be more appreciated than a copy of Bones, Inside and Out, now also available in Russian.

WW Norton   Amazon    Apple Books   Barnes and Noble   Books-a-Million   Bookshop   Hudson   IndieBound   Target   Walmart

Have you exhausted your “to-read” pandemic book list? Do you take an interest in the study of ancient humans and their predecessors? Would you like to read about scientists’ interpersonal spats mixed in with the dangers and frustrations of Ethiopian tribal warfare and government instability? Does a non-fiction book that at times reads as if it had to be made up ring your bell? If so, Fossil Men, The Quest for the Oldest Skeleton and the Origins of Humankind by Kermit Pattison (Willliam Morrow, 2020) might be a good pick.     

Early on, Pattison describes paleoanthropology: “Fossils, territory, and money were the raw materials of the discipline.” Following the 1974 discovery of “Lucy”, a 3.2-million-year-old pre-human skeleton in Ethiopia, teams of paleoanthropologists intensified their search for even older skeletons that could fill in and confirm or deny prevailing theories about the timing and pattern of human evolution. Lucy clarified that our ancestors first came out of the trees and walked upright, and then later they developed larger brains. But this information pushed farther back in time the questions of when and how. Older fossils would be enlightening.

Regarding territory, the Great Rift Valley slashes through Tanzania, Kenya, and Ethiopia. The Rift is prime fossil-hunting territory. Africa is generally considered to be the home of pre-human forms, and this long valley provides ample opportunity for bones to get washed into the basin, buried, fossilized, and then possibly exposed millions of years later. Lucy was discovered in Ethiopia; and further south in Tanzania Mary Leakey and her team discovered fossilized footprints of a humanlike creature who walked upright, 500,000 years before Lucy. How long before that had ape-like creatures abandoned knuckle walking?

After these discoveries, the Great Rift Valley, and especially its portion in northern Ethiopia, was an obvious place to intensify the search for older fossils, but this was complicated by territorial conflicts of two sorts. Warring tribes ranged over the area and were wary, and at times overtly hostile, to one another and even more so to khaki-clad foreigners driving Jeeps.

The other conflict simmered in the government offices in Addis Ababa after the military overthrow of long-time Ethiopian emperor Haile Selassie in 1974. The Ethiopians were justifiably proud of their country’s recognition as the location of Lucy’s discovery and her role in the story of human evolution. They were miffed, however, that the limelight focused on the foreign scientists and their inclinations to remove these world-heritage artefacts from their native land. These territorial issues were compounded further by changes in administrative leadership and some backscratching regarding allocation of territories for fossil-hunting rights to one team over another. Sometimes a team would sit in Addis Ababa for weeks waiting for authorizations to be signed. At times, the fossil fields were closed to exploration for years, perhaps on no more than a whim of a local official.

Regarding money, the expeditions, which were mostly from America, lasted four to five months and involved scores of scientists, grad students, camp workers, and guards. The fossil fields were a two-day drive from Addis Ababa and entirely remote; so electricity generation, water purification, and sanitation systems all required attention. Detailed casts were made of the recovered fossils that were not permitted to leave Ethiopia. Other fossils were smuggled out. At home, the investigators could study the material but needed salary support to do so. The National Science Foundation was instrumental in providing competitive grants, but some of the teams had sufficiently alienated one other regarding disputed claims that impartial reviewers of grant proposals were sparse to non-existent. Leaders in the field sometimes went unfunded and had to pare down their ambitions and also seek private support.

In addition to issues of fossils, territory, and funding, the involved paleoanthropologists seemed to have big egos, at least the ones who tended to make themselves known. Perhaps this is not surprising since they sweat for months with their noses pressed to the sand. They get excited when they discover even a solitary tooth, from which they claim, with some authority apparently, that they can identify the species of its owner.

Infighting was further compounded by the fact that the team who identified a 4.2-million-year-old possible human predecessor, Ardipithecus ramidus, nicknamed Ardi. The discoverers announced their find but did not let other scientists examine the fossils, nor did they report their analysis in the peer-reviewed scientific literature for 15 years. In the meantime, however, the finders infuriated other paleoanthropologists at meetings and in publications by discounting competing teams’ findings based on their own, but unpublished, discoveries.

The book was meticulously researched over a decade and is based on interviews with many of the principle … um … characters. Photographs of the digs, the diggers, and their finds are enlightening. Sometimes the perseverations over the meaning of an individual groove or shape of a facet on a single hand or foot bone become tediously long, especially in a book for lay readers and when the details of interest were not illustrated. You can scan those machinations without missing the book’s gist. After you’ve read Fossil Men, let me know what you think.

Related posts

Lucy, where are the rest of your bones?

Genuine hate produced the Bone Wars.

Now that we are getting out and socializing face-to-face, it is important to have conversation topics beyond what books we read during lockdown and which vaccine we received. Should the topic of moose arise, here are some facts about their antlers suitable for enriching the discussion.

Moose are a species of deer. All species in the deer family have antlers, which they shed annually. Except for caribou, only the males of each species sport such racks.  (Antelope, bison, sheep, and cattle are not deer, and they have horns, which they keep through life.)

Both antlers and horns are bone. When antlers mature each fall, the velvety covering of skin falls off, and the bone is exposed. For horns, the bone is always covered with a thin layer of keratin—the same material comprising fingernails.

Moose are the largest living species in the deer family, with bulls weighing up to 1500 pounds. The antlers account for 80 of those pounds on the big guys.

The word moose is derived from moosh (stripper and eater of bark), first used by the Innu people of Quebec. Moose eat 35 pounds of twigs and bark every day in the winter and twice that in the summer. A fourth of the energy they consume is used to support antler growth.

Moose antlers are by far the fastest growing mammalian tissue, going from zero in March to full grown in less than five months, sometimes gaining a pound a day.

They can grow that quickly because the initial thick velvety covering is laden with nutrient-supplying blood vessels. By fall, when it is time to impress the ladies, the velvety layer comes loose and falls off, but it may dangle temporarily in entirely unappealing festoons before a bull can look and feel his best.

A large rack apparently impresses the cows and intimidates the bullies, with whom the bull may occasionally spar to demonstrate dominance. Occasionally the competitors lock antlers and can’t disengage, causing them to stare directly at each other while they both starve to death.

Moose in their prime, 5-8 years old, sport the largest racks, which will include portions which extend over their brow and protect the eyes from gouging. Younger and older males get by with less.

The flat plate of antler bone is called the palm, and the extending tines are called points. The beam is the stalk that connects the antler to the skull. This terminology is important to trophy hunters. You can impress one by asking how the rack displayed in their man cave (ahem, person cave) scores on the B & C scale.

In 1887 Theodore Roosevelt founded the Boone and Crockett Club (yes, named for Daniel and Davy). It is North America’s oldest wildlife and habitat conservation organization. For rating moose-antler grandeur, the B & C score combines the spread (the record is 6 feet, 4 inches), palm length, palm width, beam circumference, and the number of points into a single brag-rights number.

Diminishing hours of daylight in late fall cause moose testosterone levels to drop, which causes their antlers to do the same in December or January. The abandoned antlers are called shed, and a late wintertime activity for outdoorspeople it to tromp moose territory hunting shed. This is illegal in some states for at least portions of the year in order to leave the habitat undisturbed for a while.

The ethics of shed hunting include not harassing a bull that is missing one antler while hoping that he will drop the other one in your presence. Sounds sensible, considering that a moose can run toward you at 35 miles per hour as easily as it can run away.

A shed sells for $4 to $12 per pound depending on the degree of weathering and damage. The antlers are valued by furniture, chandelier, and cutlery makers as well as by artists and dog chew manufacturers. Rodents and other small creatures also like shed. For them, it is a great source of calcium and other vital nutrients.

I just returned from a fabulous adventure trip in Alaska, where moose fences protect the major highways. Moose crossing signs abound, even in Anchorage. Alas, I did not see a moose, and I posed only momentarily with a shed. I did, however, collect some great dinner party facts. Now you have them too. 

Photo credits: April  https://naturallycuriouswithmaryholland.wordpress.com/2015/07/07/moose-antlers-growing/ July https://www.all-about-moose.com/moose-antlers.html August and September https://www.youtube.com/watch?v=sP7WxBFBfu4

When I was a teenager, a dentist extracted my unemerged wisdom teeth. He said they were impacted and were crowding my other teeth. Recently I found out why. It was a childhood of not chewing forcefully enough, which caused my jawbone to slightly undergrow, enough that there was no room left to accommodate my third molars, which are the last ones to erupt during growth (a dental version of musical chairs). Studies show that at least three-fourths of modern humans are similarly affected.

Our fossil ancestors did not have impacted wisdom teeth, and their occlusion was dead on—their upper and lower front teeth contacted each other precisely, which allowed for efficiency in cropping twigs and gnawing gristle off bones. These hunter-gatherers then had to chew long and hard to make these raw, tough foods digestible. Their progeny eventually quit the nomadic life and changed to a diet of roasted meat and boiled grain. Since as children these “civilized” folk did not have to gnaw and grind forcefully to nourish themselves, they developed overbites, because their jawbones failed to achieve their full growth potential. Apparently a modern diet of mashed potatoes, ground beef, boiled peas, and ice cream is not conducive to the development of a jawbone capable of comfortably housing all of our 32 teeth.

Multiple observations support this use-it-or-lose-it concept. As far back as 1871, Charles Darwin in his book, The Descent of Man, made the association between oral stress and jaw size. In recent times, anthropologist Robert Corruccini noted that elders in rural Kentucky, who grew up eating hard-to-chew foods, had better bites, despite the near absence of professional dental care, than did younger residents who grew up eating more processed foods. He observed similar bite differences in the Pima Indians before and after they had access to grocery stores and in rural and urban dwellers in India who ate diets of hard millet and tough vegetables vs. soft bread and lentils, respectively. Studies on mice (see comparative images) and monkeys have also indicated that soft diets result in smaller jaws.

Does this make you want to begin eating bark and jerky? If you are out of high school, sorry, it is too late. Like me, you can see your dentist or accept having crooked teeth, an overbite, or both. But the overbite does offer an advantage—the ability to efficiently make words starting with “f” or “v”. The linguists call these sounds labiodentals, and computer modeling says that they are 29% easier to say with an overbite than with edge-to-edge occlusion. About 4000 years ago, development of an overbite among our gruel-sipping ancestors helped spur the diversification of languages in Europe and Asia. A linguist has suggested that in ancient Rome and India using labiodentals was a status symbol, indicating wealth associated with a soft diet. Even for the poor about 1500 years ago, the Proto-Indo-European patēr, which carried over into Latin, changed to the Old English faeder. Today, labiodental consonants are present in 76% of Indo-European languages.

Perhaps I am belaboring the obvious, but as a bone lover I must extol bone. Isn’t it amazing that bone cells can respond to the presence or absence of mechanical stresses encountered during chewing and that leads to job security for dentists and to the sounds we make when speaking? Happy Fathers’ Day.

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I recently zoomed with two fellow bone lovers, both of whom have markedly elevated my respect for bones displayed in museums, to which I am gravitationally attracted.  

Mariana Di Giacomo is a natural history conservator at the Yale Peabody Museum of Natural History, and Melissa King is a preventive conservator currently on fellowship at the Smithsonian Institution. As they explained to me, a lot more than meets the eye goes into display and protection of museum fossils and bones, which are used both for education and research.

For instance, should a bone that was broken when discovered be glued back together? Doing so keeps the two parts from getting misplaced and demonstrates more closely its real-life self, but reassembly precludes access to the bone’s interior for any analysis–perhaps today for DNA or protein, tomorrow for some presently unknown test. As a compromise between reattaching the fragments and leaving them dissociated, they may make a mount that supports the pieces in their original orientation but without physically joining them.

Superglue or Gorilla Glue? No and no, emphatically. Conservators use B-72 on bone, as they do on ceramic and glass. It is a thermoplastic, non-yellowing, durable resin. They also use B-72 as a means to permanently and non-destructively label bones and fossils. They paint on a stripe of resin, hand write the identification with non-penetrating ink, and then protect the ID with another layer of B-72.

Mariana rolled her eyes when I asked what mistakes had been made in the past. With good intentions, fossils and bones have been sealed with wax, varnish, and other coatings that degrade in unsuspected ways and greatly damage the specimen’s appearance and study value. Without any surface treatment, bones and fossils on display weather away far more slowly than they would at their original discovery site; but museums contain their own destructive perils, which include sunlight, fluctuating temperature and humidity, and dust. Conservation of biological specimens parallels that of oil paintings and is approached with similar delicacy. Then before a specimen goes into a display case, the materials and coatings comprising the case are tested for any off-gassing that could damage the item. Should the display case be air-tight to prevent exposure to environmental pollutants such as acetic acid, which will dissolve bone? Or would sealing the case cause its own set of problems?

Bone that has been repurposed to make or decorate weapons and musical instruments also creates problems, particularly when it has been inset into other materials, for instance wood, which has its own conservation demands. Then for leather, feathers, cloth and other biologically derived materials embellishing crafted bone artefacts, protection from insects and vermin is key. Conservators by necessity become verminologists, learn the life cycles of these spoilers, and apply integrated pest management, which consists of various biologic, physical, and chemical means for protecting the collection while minimizing overall health and environmental issues. A non-living menace is dust, much of which is partially decomposed animal matter and which is great fodder for vermin.

Gigantic skeletal specimens, too large to encase, need to be delicately dusted from time to time; but particularly when they are extraordinarily tall or suspended from the ceiling, regular housecleaning becomes problematic. It might be easier to routinely display skeletal replicas and take them down for a bath periodically, but museum visitors like to see the real specimens. This poses its own set of problems because assembling fossil bones into a lifelike stance requires heavy metal supports, and the current trend is to mount specimens such that any single bone can be removed for analysis without disassembling the entire display. This, of course, makes the support system far more complex and visible.

Conversely, displaying replicas and leaving the real specimens in the storeroom is not without risk either. The original pieces, if not carefully labelled and catalogued, can get separated, misplaced, damaged, or lost, even if carefully protected in padded boxes inside of cabinet drawers. Of course, that degree of protection is not possible for fossils that are measured in feet and in hundreds of pounds.

Overall, my conversation with Mariana and Melissa heightened my appreciation for the care that goes into bones displayed and preserved in museums. Fine art conservation and restoration make the news from time to time. Bone deserves (and is receiving) the same level of care and should be equally celebrated. 

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Follow up on the recent post: Marking Time in Prague. A reader commented that the Prague Old Town Square in front of the ancient clock was the local pickpockets’ favorite location. I can imagine: everybody relaxed, looking up, likely getting jostled a bit, robbed–another peril avoided by traveling virtually!

Out of the roughly 206 bones in our body, the hyoid bone is the only one that is entirely separated from the rest of the skeleton. Vesalius in the 16^th century recognized its isolation and depicted the hyoid resting on the plinth like a set of false teeth. Being U-shaped, it is appropriately named after the Greek letter upsilon. The hyoid bone resides immediately under the jawbone, just above the thyroid cartilage (Adam’s apple in men). Here 12 muscles attach that are critical for swallowing and vocalizing. In this well-protected position, it doesn’t get much notice and is rarely broken. Strangulation is the exception, so the coroner in your detective novel might want a look at it.

In humans, and uniquely so, the hyoid bone is moveable, which has been one of the evolutionary changes important for speech development. Its mobility, however, also contributes to obstructive sleep apnea. As the attached base-of-tongue muscles fall backwards in relaxation, they narrow the airway in the throat. Otolaryngologists counter this by drawing the hyoid approximately an inch forward and tethering it with strong sutures either to the inside of the jawbone or to the top edge of the thyroid cartilage. I would think that this might affect speech or swallowing, but the research papers say otherwise.  

Don’t confuse the hyoid bone with the wishbone, which is present in some birds and their dinosaur relatives. The wishbone is farther down the neck, is a fusion of those animals’ collar bones, and contributes to efficient flying in some species. (See previous post: Twelve No-Fail Conversation Starters About Wishbones.) By contrast, all vertebrate animals have a hyoid bone, although it varies widely in shape and function. Here are two examples.

The hyoid bone helps a woodpecker pound its beak 22 times a second, 12,000 times a day, without apparently giving itself headaches. The beak is a bit flexible, which absorbs some of the shock, as does a thick pad of spongy bone that separates the beak from the skull. The hyoid bone handles the rest. It starts in the neck, like in the rest of us, but then curls around behind and over the skull to attach next to a nostril, thus bypassing the brain. It is thin and fragile looking.

Not so for the endangered howler monkey. Its hyoid bone is about the size and general shape of a 4-ounce, round-bottomed measuring cup. That is almost half the size of the monkey’s skull. The hyoid is instrumental in the howler’s ability to project its voice two miles.

Given the relative numbers of howlers and humans, it’s good that we are not so well-voiced.    

Published in abbreviated form in NYT Book Review Letters, March 21, 2021

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With the exception of those living in caves, I suspect that everyone has heard the current and widely disseminated advice regarding the health benefits of walking or jogging 10,000 steps a day. In addition to improving cardiorespiratory health and acquiring some sunshine-derived vitamin D, the repeated impact of feet on pavement is critical for maintenance of bone health. Although swimming and cycling are great for the heart and lungs, they do not jolt the bones sufficiently for them to maintain their density and strength.

The heart is entirely dependent on a steady supply of calcium for its health, and if there is not enough calcium coming in through intestinal absorption, hormones release calcium from bone to the heart’s benefit but to the skeleton’s detriment. Bones attempt to counter this wanton thievery by constantly remodeling themselves and strategically adding new calcium crystals in areas where the bone cells sense mechanical stress. This is particularly critical in the hips and spine, since fractures here can be permanently life-changing if not life-ending. For women, menopause brings added peril, because the absence of critical hormones diminishes bone density, i.e., the shortage causes bones to become porous, i.e., osteoporotic.

Regular impact exercise counters this tendency and underlies the recommendation for achieving 10,000 steps a day. It is hard enough to do this on Earth but is nearly impossible in the near-zero gravity of space. Weight lifting is futile, because barbells float. Magnetic shoes might work but would risk interfering with the complex electronics on board. Futurists have also considered creating artificial gravity by spinning part or all of the spacecraft, making it a large centrifuge. Theoretically this would work, but the cabin would either have to be 100 feet in diameter or spin at a rapid, energy-​consuming speed, neither of which seems practical.

Presently, International Space Station inhabitants fasten a harness around their shoulders and waist and hook it with bungee cords to a treadmill to keep from floating away while they jog. Nonetheless, astronauts loose bone mass at ten times the rate seen in postmenopausal women, and a six-month stay on the ISS causes a 10 percent loss of bone. This rate would be unsustainable on a three-to-four-year roundtrip journey to Mars.

Maybe once they get to Mars, could travelers bulk up their bones in preparation for their zero-gravity trip back to Earth? Gravity on Mars is one-third that of Earth’s. Nobody knows whether that is enough to maintain or restore bone health. Then if travelers wanted to take their families along or have families en route, they would have to deal with the unknown effects of low gravity on growing bones. Nonetheless, kids would undoubtedly have a blast doing cartwheels and flips during the entire adventure.

Solutions might come from a surprising source—hibernating bears. It’s Spring, and bears are beginning to rouse themselves from four to five months of complete indolence, yet they come through without a trace of diminished bone density. Brave investigators have darted grizzlies and similar species and sampled their bone and blood immediately before, during, and after hibernation. (Who said that studying bone hormones had to be dull.) The researchers have found that a bear’s bone metabolism essentially shuts down along with its other bodily functions during hibernation, which proves to be a highly complex, multisystem process affecting the brain, heart, kidneys, muscles, and bone. Investigators understand the process incompletely, so time will tell if bears can offer humans some help with bone health. In the meantime, it’s Spring. Anyone for a walk?

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*Excerpted in part from

Despite the pandemic, my wife and I have “traveled” internationally every Wednesday since July. Our imaginary private jet flies at the speed of light, so we happily skip security checks and avoid jet lag. We start the day in our on-board bed by listening to our destination’s national anthem and googling what the locals have for breakfast. Later we join Rick Steves and Barby at Geography Now, both of whom are fountains of knowledge about our chosen country. Continuing on YouTube, we delve into the nation’s language quirks, sports, dog breeds, best and worst parts of visiting, cuisine, politics, national parks, and so on. Living in multi-cultured Los Angeles, we have only once missed being able to order a pick-up dinner of that country’s cuisine. (There don’t seem to be any Croatian restaurants near by!) We round out our trip by watching a locally made movie. We have seen some great ones. Just google “best films from __________.”

Why am I telling you about our virtual travels? First to recommend such trips—highly educational and diversionary. Secondly, everywhere I go I find some unique bones, and last week’s visit to the Czech Republic was no exception.

A huge clock has graced the wall of Prague’s Old Town Hall since 1410, which makes it the world’s oldest working astronomical clock. If you want to know the local time and current date, the sidereal time (ask an astronomer to explain), the Old Bohemian time (ask an old Bohemian), Babylonian time, or the current position of the sun, moon, Zodiac constellations, and other planets, the clock will show you. It also indicates the time of today’s sunrise and sunset and which saint is having his feast day.

So far, jaded Rolex owners may not be impressed, but there’s more. Enough that crowds gather on the hour to watch the show. Two small doors above the dials open, and carved figures of the Apostles parade past. Above the Saints, a golden rooster flaps its wings. Carved figures also flank both discs. The lower set, to symbolize goodness, represents an archangel, philosopher, astronomer, and historian. The other set represents disdainful activities. A vain man shakes his head as he sees his reflection in a mirror, a miser rattles his purse, a skeleton rings a bell and turns an hourglass over (hint, hint), and a hedonist stands frozen in extravagance and pleasure.

Naturally, I have to critique the skeleton’s anatomical correctness. Both hips are dislocated, but otherwise it looks pretty good. The pigeon netting helps.

By itself, a clock, even one with some bones, is probably not worth a trip to Central Europe. Presently, however, when time seems to be standing still, appreciating a mechanical marvel over 600 years old, one that has witnessed numerous bouts of political and disease-induced turmoil, is a good reason to acknowledge the capacity to keep on ticking.  

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Valentine’s Day conjures up sweet images of romance that humans typically associate with roses and chocolate. Casanova, however, had his own ideas about heightening sexual desire and shared large platters of raw oysters with his lovers, even though no solid evidence supported or supports this indulgence. “We sucked them in, one by one, after placing them on the other’s tongue. Voluptuous reader, try it, and tell me whether it is not the nectar of the gods!”  Imagine, however, how much easier it would be to consume oysters unshucked and just crush the shells in your throat before swallowing the treat.

Perhaps efficient, but unappetizing and certainly not sexy, you say. Nevertheless, many fish perform these feats, thanks to teeth embedded in a second set of jaws that is located in their throat. These bones and teeth have likely developed independently in various types of fish, including flying fish, tilapia, and sunfish as well as in common aquarium dwellers such as angelfish.

Two adaptations of pharangeal jaws are particularly remarkable. Mobility characterizes the first. After a moray eel captures a meal with its oral teeth, it opens its pharangeal jaws, moves them forward to grasp the prize, and pulls it irreversibly into the eel’s digestive system. Researchers think that morays developed this mechanism as a result of living in tight burrows where they could not expand their bodies sufficiently to create negative pressure, necessary to draw prey deep into their mouths. Fortunately, that is not an issue with humans consuming chocolate, at least not until clothes become too tight.

An even more amazing adaptation is one characterized by strength. Black drums, also known as drums and drummers, are common along the East Coast of the United States and in the Gulf of Mexico. They typically weigh five to thirty pounds but can grow to over one hundred. Their hardened pharangeal jawbones and accompanying strong muscles are adapted to crushing crabs and other shellfish, and drums find oysters particularly delectable. Fishermen look for drums in oyster beds and sometimes see their tails sticking out of the water, which results from the drums’ habit of bottom feeding in shallow areas. And feed they do. In a day a drum can consume roughly one commercially sized oyster per pound of body weight. For me, that would be 170 oysters, far more then I would either want to shuck or to crush and spit out the shells.

Whether black drums are affected romantically by sharing a bed of raw oysters is yet to be determined. But without a pharangeal jaw, I’m sticking with chocolate and a sentimental card, both safely obtained online. Happy Valentine’s Day.

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When he wasn’t hating his paleontology archrival in some tangible way, Edward Drinker Cope* was discovering and naming fossil fauna. In 1892 he found a dog-like creature with skeletal features suggesting its jaws could crush bones with impunity. These features included oversized premolars placed in a short, robust jaw, which provided wide attachment areas for muscles. Drinker named the beast Borophagus (gluttonous eater). Based on the presence and measurements of other skeletal parts found across North America, it roamed widely between 16 and 2 million years ago and weighed about 50 pounds. Its mighty bite force allowed it to occupy a unique ecological niche, presently represented in Africa by the spotted hyena. Because “Boro” could crack open large bones and savor the marrow within, it could stay back and let other large carnivores finish their meal and then enjoy their leftovers. Or maybe they hunted in packs as hyenas do, devouring large prey, bones and all, within a few frenzied minutes. In that case, Boro would have an advantage if it could snap off an entire leg and trot off to enjoy it in peace.

Because Drinker and subsequent paleontologists had just the bones, they were unable to determine anything about Boro’s behavior. Was it a hyena-like pack animal? A scavenger? A predator? Answers have come recently from a surprising source—its fossilized poop.

While boating on Turlock Lake, east of Modesto, California, an amateur fossil collector recognized a blob on the shore as a coprolite, scientific parlance for feces turned to stone. It had fragments of bone visible near the surface, so the collector surmised that the donor was a large carnivore, and Boro was the only known carnivore from that time in that area. He dug around and recovered 14 coprolites, which became the material for a 42-page scientific publication.

The fact that Boro and company dropped feces in clusters, which is how wolves and spotted hyenas mark territory, implied to the investigators that they were social animals and that the fossil collector had come across their outhouse. Computed tomography analysis of the coprolites revealed bone fragments that came from ribs or limbs of animals as large as 220 pounds, the size of today’s mule deer. Although some of the bone fragments were nearly 2 ½ inches long, most were in the quarter-to-half-inch range, which made the source generally unidentifiable, although one clearly came from a  bird wing and another from a beaver jaw. The investigators suggest that Boro’s habit of crushing bone accelerated recycling of the contained nutrients into the food web and remark that no animal took Boro’s place following its extinction. Modern day carnivores living in the area (coyotes, foxes, cougars) do not have Boro’s bone-crushing capabilities, which indicates a fundamental shift in food web dynamics—quite a lesson derived from a latrine.