Wagging Tails Break Bones

Imagine that you are a tyrannosaur rumbling around 76 million years ago in what is now Montana. As fearsome as you are, you are in mortal danger from a low-slung herbivore half your size and weight, even though you may have one for dinner now and then. The rub is that Zuul crurivastator had a tail to kill for, or rather, to kill with. Zuul’s tail was nine feet long with a club at its terminus the size of a 3-inch-thick cafeteria tray. The knob enclosed two large, heavy osteoderms, which are bony plates in the skin seen today in armadillos, crocodiles, and Gila monsters, but with much smaller dimensions. Many dinosaurs possessed osteoderm armor, but tail clubs were unusual. If Zuul flailed its tail and hit your shin bone (remember, you are a Gorgosaurus or other tyrannosaur of the time*), it could render you much less tyrannical, perhaps fatally cripple you. And the fossil record does include various tyrannosaur skeletons with such injuries. Not coincidentally, “crurivastator” means “destroyer of shins.”

Well, the described scenario has been circulating for years and might be of interest for a Jurassic Park sequel, but evidence now suggests that it is wrong. A recent report opines that Zuul wagged its tail violently not to ward off predators but rather to fight over mates, similar to the way modern-day bison and mountain goats butt heads–not to the death, but to establish preeminence. So, you may ask, what is the evidence for a Zuul mating ritual? Intriguing to say the least.

In 2014, paleontologists were using a Bobcat frontend loader to rapidly remove a 39-foot “overburden” of stone sediment to expose the geologic layer that they were interested in exploring. The machine unexpectedly scraped across the surface of a Zuul’s tail club. Because the animal’s fossilized skeleton had not been exposed to erosive forces since it was originally covered with silt 76 million years ago, it was in pristine condition—99% complete including tail and trunk osteoderms in their original positions along with some skin and non-bony keratin scales and sheaths of the creature’s many spikes. (Keratin is the protein that constitutes nails and hair and covers bird beaks and cow horns.) Since keratin and skin are not normally preserved in the fossil record, this Zuul was deemed a “dinosaur mummy.” The Royal Ontario Museum purchased the two 15-ton blocks of stone that encased Zuul and then spent years with magnifying lenses, micro jackhammers, and paint brushes tediously extricating Zuul from its stone tomb, as highlighted in this three-minute descriptive video.

Osteoderms on the beast’s flanks were of particular interest because they showed signs of fracture, whereas signs of similar injuries to osteoderms on the rest of the body were uncommon. The injuries were not inflicted by piercing teeth or slashing claws rendered by a tyrannosaur, rather they resulted from blunt, heavy blows. Furthermore, the damaged osteoderms showed differing degrees of healing, implying that the insults were sublethal and recurrent, perhaps even ritual. Paleontologists have yet to determine the sex of any dinosaur, so you are free to speculate whether these osteoderm-damaging encounters involved competing Zuul females or males.

OK, it’s time to stop envisioning yourself as a tyrannosaur. Rather imagine the myriad yet-to-be-discovered fossils, which will reveal prehistoric animals’ anatomy and also maybe their behavior. Thank you, bone.

*The best-known species of tyrannosaurus, Tyrannosaurus rex, did not live at the same time as Zuul, but rather 8-10 million years later.


Launching June 13, 2023

pre-order now from the publisher, WW Norton, or from

An entertaining illustrated deep dive into muscle, from the discovery of human anatomy to the latest science of strength training.

Muscle tissue powers every heartbeat, blink, jog, jump, and goosebump. It is the force behind the most critical bodily functions, including digestion and childbirth, as well as extreme feats of athleticism. We can mold our muscles with exercise and observe the results.

In this lively, lucid book, orthopedic surgeon Roy A. Meals takes us on a wide-ranging journey through anatomy, biology, history, and health to unlock the mysteries of our muscles. He breaks down the three different types of muscle―smooth, skeletal, and cardiac―and explores major advancements in medicine and fitness, including cutting-edge gene-editing research and the science behind popular muscle conditioning strategies. Along the way, he offers insight into the changing aesthetic and cultural conception of muscle, from Michelangelo’s David to present-day bodybuilders, and shares fascinating examples of strange muscular maladies and their treatment. Brimming with fun facts and infectious enthusiasm, Muscle sheds light on the astonishing, essential tissue that moves us through life.

Deceptively Named Restaurants

Should travelers find themselves in unfamiliar surroundings when it is time to eat, a restaurant’s signage often signals its featured cuisine. For instance, Waffle House, International House of Pancakes, California Pizza Kitchen, Steak n’ Shake, Taco Bell, and Red Lobster aren’t keeping any secrets.

Yet it is hard if not impossible to ascertain the featured fare of other eateries, especially high-end ones. A listing of the world’s 50 best restaurants includes only one, Casa do Porco in Sao Paulo, House of the Pig in Portuguese (ranked #5), that hints at its menu. Some of the top restaurants have names that seem meaningless. These include Diverxo (#4, Madrid), The Jane (#21, Antwerp), and Sorn (#39, Bangkok). When translated, others have names that have meaning, but their relationship with food is murky. Take, for instance, Pujol (Small Hill, #5, Mexico City), Septime (a position in fencing, #22, Paris), and Belcanto (A Beautiful Song, #46, Lisbon). Then there are ones that worry me. I can only hope that their names have nothing to do with what they serve. Otherwise, what might you expect to find on your plate at Geranium (#1, Copenhagen), Nobelhart and Schmutzig (#17, Berlin), or The Chairman (#24, Hong Kong)?

You are probably asking yourself, “What’s the point of this discourse in a blog supposedly focused on muscle and bone?” Well, every non-vegetarian restaurant serves muscle, but I challenge you to find one that has muscle in its name. (Bertha’s Mussels in Baltimore gets close. Even so, it recently closed.) Bones are another matter. A quick google search turned up more than 50 U.S. eateries with bones in their names, but they rarely if ever serve bones. (Maybe that’s why none are listed in the international top 50.)

Smokey Bones is a chain of about 60 establishments in 16 Eastern states, otherwise, bone-related restaurants seem to be one-offs. They are scattered widely and have names such as Shell and Bones (New Haven), Bourbon and Bones (Scottsdale), Fish Bones Grill (Lewiston), Chicken Bones (Baltimore), Dirty Bones (Dallas), and Rice and Bones (Berkeley). But really, are these establishments luring you in for a savory platter of marrow bones and a steaming cup of bone broth*? Aren’t they really saying that you should come have some meat, perhaps still on the bone? Yet nobody is straightforward and calls their eatery Meat or Flesh or Muscle. It seems that bones in the name is just thinly veiled code for we-specialize-in-serving-animal-derived-protein. Perhaps the subtlety is designed to mollify vegetarians.

After stewing over this possibility, I decided it would be safer and more palatable to sample a bones-named restaurant rather than one dishing out pujols, chairmen, or schmutzig. I chose Bones in Atlanta. It has been an institution since opening in 1979. Its website unabashedly states, “Bones has received the Best of Atlanta Steakhouse Award each year for the past sixteen years. Recently, Zagat recognized Bones as having the highest rating for food and service of any steakhouse in America.”

Their lunch menu includes Bones Lobster Bisque, Bones Burger, and BLT with Bones Bacon. I am guessing that these dishes do not have bones in them but are just some of their signature plates. The same goes for dinner. Their Bones Seafood Platter is offered along with an array of steaks, chops, and seafood. It appears, however, that the only time diners can actually have a bone brought to their table is when they order a “bone-in” filet or rib-eye.

So as a bone lover, I was disappointed about the disconnect between Bones’ name and its fare, but I was fully pleased with the ambient setting, good service, and great food. I agreed with this Zagat reviewer. “Bring a big appetite…to this ridiculously decadent power steakhouse that beats those national chains hands down.” I had scallops because they fit my cholesterol and monetary budgets better than their land-derived meat options, bone in or out. On leaving, I received a box of faux bones to gnaw on at bedtime.

To my reckoning, the only restaurant that has a legitimate claim to its osseous name is Hueso (bone in Spanish) in Guadalajara. There, 10,000 bleached bones adorn the walls. Regardless of what Hueso serves, I can’t wait to visit.

Hueso, Guadalajara

* See the previous post relating to eating bone: Bone Broth, My Quest for the Best.


Launching June 13, 2023

pre-order now from the publisher or from

An entertaining illustrated deep dive into muscle, from the discovery of human anatomy to the latest science of strength training.

Muscle tissue powers every heartbeat, blink, jog, jump, and goosebump. It is the force behind the most critical bodily functions, including digestion and childbirth, as well as extreme feats of athleticism. We can mold our muscles with exercise and observe the results.

In this lively, lucid book, orthopedic surgeon Roy A. Meals takes us on a wide-ranging journey through anatomy, biology, history, and health to unlock the mysteries of our muscles. He breaks down the three different types of muscle―smooth, skeletal, and cardiac―and explores major advancements in medicine and fitness, including cutting-edge gene-editing research and the science behind popular muscle conditioning strategies. Along the way, he offers insight into the changing aesthetic and cultural conception of muscle, from Michelangelo’s David to present-day bodybuilders, and shares fascinating examples of strange muscular maladies and their treatment. Brimming with fun facts and infectious enthusiasm, Muscle sheds light on the astonishing, essential tissue that moves us through life. 90 illustrations

Eugen Sandow, The Father of Modern Body Building

Concurrent with the modern Olympic movement, the emphasis on the perfect human physique came to captivate Prussian Eugen Sandow (1867-1925). He described his early teenage self as weedy, fragile, and pale-skinned. When he was fifteen, his father took him on a trip to Rome where the young man became infatuated with the brawny brutes represented in Greek and Roman statuary. He dreamed of emulating them, and on return home Sandow committed himself to achieve a state of physical perfection. To determine exactly what the “Grecian ideal” should be, he visited museums and measured statues’ various dimensions.

Then taking tips from circus strongmen, Sandow began pumping iron to achieve the Grecian ideal of broad shoulders, tapered back, small waist, and detailed but overwhelmingly huge muscles. He performed lots of reps. It worked (and it still does).

Sandow stressed the aesthetics of muscle size and definition over strength, but he became strong in the process. At eighteen, he left home and toured Europe first as a circus athlete and professional wrestler and later as a weightlifter. Eventually, Florenz Ziegfield contracted him to show off in Chicago at the 1893 World’s Columbian Exposition. Once they discovered that the audiences were more interested in Sandow’s robust physique than in how much weight he was lifting, Ziegfield asked him to pose and flex in what he called “muscle display performances” to highlight various muscle groups.

Subsequently, Sandow traveled the world, published Sandow’s Magazine of Physical Culture, and name-branded a line of cigars, possibly the first celebrity endorsement of a commercial product. In his performances, Sandow dazzled audiences with feats of strength such as lifting pianos, bending iron bars, bench-pressing cows, and tearing decks of cards in half, a stunt for which Sandow was once bested. A young man in the audience, who later became the “World’s Strongest Youth,” jumped on the stage, took half of the torn deck from Sandow, and tore it in half again.

In 1901, Sandow hosted the first major bodybuilding show, “The Great Competition,” for an overflowing crowd at the Royal Albert Hall in London. Clad in leopard-skin leotards, the sixty contestants flexed their muscles for the enthusiastic crowd and the discerning eyes of the three judges, who were Charles Lawes, a sculptor and athlete; Arthur Conan Doyle, author and friend of Sandow’s; and Sandow himself. The winner received a gold-plated statuette of the competition’s nearly naked host.

For all these accomplishments, Sandow is known as the father of modern bodybuilding. (Take note, bodybuilding contests stress form, not strength. By contrast, powerlifters and Olympic weightlifters are not judged at all on their appearance, just on their strength and explosive speed, respectively.) Sandow inspired the golden age of body builders, which included Steve Reeves, Frank Zane, and Arnold Schwarzenegger. Today, the award for the Mr. Olympia contest is “The Sandow.”


Launching June 13, 2023, Pre-order now

pre-order now from the publisher

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The Tooth Is Mightier Than the Bone

Despite my unwavering respect for bone because of its durability and hardness, I must admit that teeth are equally durable and even harder. The tooth’s enamel is the hardest substance in the body and consists almost entirely of the same calcium crystal that constitutes bone. Enamel, however, has none of the collagen meshwork that give bones a bit of resiliency when suddenly stressed, so teeth are far more brittle.

Bones come in vastly more shapes and sizes than teeth and have the same collagen/calcium composition through and through. By contrast, teeth have multiple layers of differing compositions and attributes.  Supporting the crown and extending to the tips of the roots, the dentin is softer and more porous than the enamel. Dentin surrounds the pulp, where a tooth’s blood vessels and nerves reside and where endodontists make their living performing root canals. Covering the dentin below the gum line is a thin layer of cementum, which is softer than both enamel and dentin. Its principal function is to support what dentists blithely call the PDL—periodontal ligament. I object to this name, because bone lovers know that ligaments span from bone to bone across joints, stabilize them, allow motion in some directions, and prevent motion in others. When I posed this flagrant misuse of the term ligament to my dentist, he lamely responded that the PDL spans from bone to tooth and stabilizes the roots in their sockets. For the most part, however, motion between tooth and bone is undesirable, so I think the PDL, which is about as thick as several sheets of paper, should be called the periodontal membrane or covering. Yet my opinion is apparently not shared with those who love teeth more than bones. (In the US alone, dentists outnumber me nearly 200,000 to one.)

Regardless of what it is called, the PDL is responsible for this essay’s title, because if teeth and bones become engaged in a shoving match, teeth win. This is because pressure on a tooth causes specialized bone-dissolving cells in the areas where the PDL is being compressed to remove bone and let the tooth move along. In its wake, specialized bone-forming cells fill the void. Voila, orthodontics is born.  

Humans have been relying on the PDL to perform this bone-defying feat as far back as ancient Egypt, where mummies have been discovered with metal bands wrapped around their teeth. Archaeologists surmise that long-gone fibrous strands tied the bands together to create tooth movement and beautiful toothy grins. Primitive orthodontic appliances also appear among ancient Greek and Roman artefacts.

A major advance came in the 18th century, when Pierre Fauchard, known as the Father of Modern Orthodontia, began wiring arched metal strips to the teeth to get them moving. To achieve an even greater mechanical advantage, an 1822 invention enhanced the shoving match with external headgear, although it probably did not enhance the user’s social standing while movement was underway. An 1840 book, The Dental Art, described soldering knobs on the metal arches to which rubber bands could be attached and that greatly reduced the need for external headgear. Now, many orthodontic appliances are nearly invisible.

In addition, tooth movement can be accelerated by drilling small holes into the bone surrounding the target teeth. This weakens the bone and stimulates activity in the bone-dissolving cells. Enterprising orthodontists have also capitalized on bone’s accommodating nature to improve the bite efficiency and smile (or snarl?) of man’s best friends.

I suppose some dentists dream of taking on greater challenges in the animal realm, but I just hope they appreciate that any change stems from bone’s calm, controlled response to stress. It just moves away from those tooth-root bullies.


Should you need another conversation starter, try this. Growing evidence supports the theory that teeth developed from scales on the outside our finny ancestors’ bodies and gradually migrated inside while morphing into enamel, dentin, cementum, and the PD … layer.


Are you looking for the perfect holiday gift? Nothing expresses your sincerity, big heart, and generosity more than a subscription to this blog MuscleAndBone.Info (free) and a copy of Bones, Inside and Out, modestly priced at your favorite bookseller.

“White meat or dark meat?”

The title question just shouts Thanksgiving, but what’s the basis of it? Equipped with the following answer, you will be the center of festive table talk again this year. Here is the gist of it–in a roundabout way.

Skeletal muscles differ from one another according to whether they are suited better for short-term, powerful demands or sustained moderate contractions. Those muscles capable of producing sudden, explosive contractions are categorized as fast twitch because they can contract up to seventy times per second; but they can only do so in short bursts before they fatigue. By contrast, slow-twitch fibers can repeatedly contract at a much lower rate for hours without tiring.

Some people naturally have more fast-twitch or slow-twitch muscle fibers than others; and to capitalize on what nature provided, athletes gravitate to physical activities that best highlight their attributes. People with a preponderance of fast-twitch muscle fibers are good at sprinting, jumping, and power lifting; all are endeavors that require sudden short bursts of power, which are over before any oxygen debt is realized. Conversely, athletes endowed with a preponderance of slow-twitch muscle fibers will find their efforts better rewarded in endurance activities such as rowing, cross-country skiing, and long-distance running. These endeavors require a steady supply of oxygen over many minutes or even hours.

Guess which type of muscle fibers these fabled racers had?

Getting back to Thanksgiving table talk, turkeys have both types of muscle. They use their breast and wing muscles to flap their way onto tree branches. This requires sudden forceful contractions, the kind of activity provided by fast-twitch muscles. By contrast, while leisurely scratching and strutting throughout the day, the birds rely on the slow-twitch muscles that populate their legs and thighs. These muscles’ constant and prolonged demand for oxygen is supplied by the abundance of a reddish molecule known as myoglobin, muscle’s version of hemoglobin. When heated, myoglobin turns brown—hence the term “dark meat” for cooked turkey thighs and legs. The breasts and wings are “white meat,” because these fast-twitch muscles have far less myoglobin.

Astounded as your dinner table companions will be with your grasp of turkey muscle physiology and biochemistry, they may wonder why you have wandered from your annual fascinating discourses on the glories of bone, some of which aboutbone.com has previously highlighted:

Explain that muscle is bone’s closest friend, and an in-depth understanding of one demands an equal grasp of the other. With that in mind, the blog, now renamed to reflect this companionship, will begin extolling the virtues of both, separately and in combination.

Happy Thanksgiving feasting–and yakking.

A Snake’s Breathtaking Embrace

Rather than envenomating their prey, many snakes get a toothy hold on their next meal, coil their serpentine body around it, and squeeze. They soon asphyxiate their prey. Anacondas, pythons, boa constrictors, as well as less-fearsomely sized king, gopher, and bull snakes all prepare dinner this way.

These facts have caused inquiring minds to wonder, “Why don’t snakes asphyxiate themselves with the pressure exerted on their own lungs during this embrace?” Scientists now have the answer. To understand it, here’s a bit of snake anatomy.

Snakes ribs, as many as 200 pairs, float. In other words, the ribs attach at only one end, to the spine. Therefore their skeletons readily adapt to changing body girth, for instance when an anaconda swallows a pig. For comparison, the top ten pairs of human ribs attach to the breastbone as well as the spine, and only the lower two sets are floating.

Additionally, constrictors have a special muscle attached to each rib and to the spine. Known as the levator costa, this muscle’s contraction lifts the rib upward and outward to expand the body cavity. That is important, because snakes do not have diaphragms, so the only way they can pump air in and out of their lungs, which extend back about a third of their body length, is to contract and relax their levator costa muscles. That works fine when the snake is resting or on the move.

When it embraces its prey, however, the snake also equally embraces itself and therefore cannot breathe, at least in the portions of its body performing the deadly hug. Can constrictors activate their levator costa muscles selectively, breathing with ones not involved in the squeeze? That would be efficient but would require sophisticated neural control—somewhat analogous to humans breathing in and out of just one lung. Enterprising investigators found the answer by applying standard, human blood pressure cuffs around the bodies of boa constrictors and placing masks over their faces (the snakes’, not the investigators’). Then the researchers studied rib motions in both constricted and unconstructed portions by recording electrical activity and video X-ray images. By placing the blood pressure cuff in different locations along the snake’s trunk and repeating the pressurizations, the investigators determined that constrictors exclusively use levator costa muscles only in free areas and do not even attempt to breathe using the muscles in the pressurized areas. They (the investigators, not the snakes) call the phenomenon modular lung ventilation, which allows constrictors to squeeze and breathe simultaneously. Bones, muscles, and nerves working together. This amazing efficiency of nature will definitely provide me some solace if I ever encounter a python’s embrace.    

This time last year, I posted A Plea for Anatomical Correctness at Halloween. Apparently the plea went unheeded, because I have recently seen these frightful creatures. Rest assured, the Bone Police are on their way. Let me know if you spot other cases of osseous infractions, and I will report them to the authorities.

About Bone Turns Five

September 17 probably came and went without you recognizing that it was About Bone’s fifth birthday. I started blogging then in 2017 because I wanted to write a book about bone. Before accepting such a proposal, a publisher wants to know that the author has a “platform.” This might be, for instance, 10 million twitter followers or international visibility in the daily news. So to entice a publisher, I started blogging to increase my platform.

A year later when I submitted the proposal for Bone, Inside and Out, to publishers, WW Norton bit, even though my platform was somewhat less impressive than John Grisham’s or Jennifer Aniston’s.

After WWN accepted the final manuscript for Bone in December 2019, I discovered that I had more stories to tell about bone. Some topics hadn’t fit in the book. I also found new topics, and readers suggested others.

Feeling ambitious, I started blogging every week, but I soon discovered that each post was very time consuming because I wanted to put bone’s best foot forward. Now, I post every three to four weeks. That is a pace I can sustain and which I hope will not overburden loyal readers.

Today’s post is #105. The most popular posts in 2021 were

Bone or Ivory? A Cautionary Note for Collectors and Gifters (2017)

Serpent slither from the sea, meaning is ambiguous. (2020)

The Versatile Cannon Bone. What Is It? (2018)

Skulls in Fine Art (2018)

The dates in parentheses indicate the year that the article was posted. So you can see that interest in bone is durable. If you find yourself in solitary confinement or trapped on a desert island that happens to have internet connection, you might enjoy scrolling through the archives and reading/rereading some of the other 100 posts.

I could probably continue blogging about nothing other than bone forever, but I have decided to extend my reach and begin including posts on bone’s closest friend: muscle. Many of the upcoming posts, beginning with #106, A Snake’s Breathtaking Embrace, will feature interesting information on both bone and muscle.

WW Norton found my relatively paltry but slowly enlarging platform acceptable because they have agreed to publish Muscle, The Gripping Story of Strength and Movement in June 2023. They now have the final manuscript, and Muscle is in production. (Remarkable to me but characteristic of the industry, a publisher typically requires nine months to turn a manuscript into a finished product.) I will keep you informed as I sign off on jacket design, ask notables to write endorsements for the back cover, and other milestones.

In the meantime, join with me in celebrating About Bone’s fifth birthday. An author’s platform can never be too big, so let your social media contacts know how much fun reading about bone and muscle can be.

Rick Steves signs off with “Keep on traveling.” I say, “Keep on learning.”

Puzzling Skeletal Anatomy

Four facts: I am attracted to activities that many people would consider tedious. I love bones. August was too hot to enjoy being outside. Some friend or foe, I don’t remember who, sent me this.

I accepted the challenge.

As puzzle pros do, I started with the border pieces, each having a black margin and a straight edge. I thought this part would be easy.

But some of the pieces were so fiendishly similar to one another that the left border was longer than the right for several unhappy hours.

The yardstick and the closest possible scrutiny aided getting the vertical borders equal–25 pieces across, 40 pieces up and down, 1000 in total, 21″ x 28″. I used the muffin tray to sort pieces when I thought I could identify pieces’ anatomical region or read the small print on the labels.

The central figure was the easiest because it was outlined in black and had the fewest pieces.

Reading glasses, a magnifying lens, and Jazzy helped reduce frustration.

Once the images and labels were in place, 88 entirely blank pieces remained.

A baking sheet allowed me to scrutinize these final pieces in concert, first from one angle and then another.


What did I (re)learn by assembling the puzzle?

Wrisberg’s ligament is in the knee. The nuchal ligament is continuous with the supraspinus ligament. (I had to google those facts in order to place those pieces properly.)

When a piece includes part or all of the term epicondyle, it could be pointing to any of the 7 knee images or 4 elbow images.

My satisfaction was not greatly diminished when I discovered that one piece was missing, even after searching the vacuum cleaner bag. (For the sake of the above image, I improvised the missing piece.)

What have I learned subsequently?

The puzzle is derived from a wall chart drawn by a Peter Bachin in 1947. The wall charts are available at Amazon in sizes as big as 42″ x 62″, which would be large enough to read the labels without magnification.

Bachin also drew a poster of the muscular system, which for the sake of our dining room décor and my sleep schedule, is not available in puzzle form.

Addendum January 2023: Frank and Susan Grispino, both hand therapists and friends of mine, expressed interest in the puzzle after I blogged about it, so I completely disassembled the puzzle and sent it to them. Along with their computer-science-major son, they recently completed the puzzle and offer these tips to anybody equally masochistic. 1. The puzzle pieces are wider than they are tall, so there are only two, rather than four, possible orientations. 2. Knowledge of skeletal anatomy helps but takes backseat to personalities that are stubborn, task-oriented, and competitive. (Apparently all three Grispinos qualify here.) 3. Assemble the border pieces first. 4. Sort identifiable pieces by anatomical region. 5. Use a lighted magnifying class or cell phone to identify the nearly microscopic text on some of the pieces. 6. Look for similar lines and colors on multiple pieces. 7. Save the entirely unmarked pieces until the end. 8. “If you are on a roll, keep going. If you are experiencing puzzle block, take a break.”

Who’s next to accept the challenge? Contact info@MuscleAndBone.info

The Incredible Shrinking Bones

Courtesy Aquaimages, Wikimedia

Despite Charles Darwin’s reputation for being a respectful observer and recorder of animal life, he apparently had a “least favorite” list topped by marine iguanas. In great numbers, these lizards populate the Galapagos Islands, which straddle the equator 800 miles off the coast of Ecuador. Darwin visited in 1835 and wrote, “The black lava rocks on the beach are frequented by large (2–3 ft), most disgusting, clumsy lizards.” It is “a hideous-looking creature, of a dirty black colour, stupid and sluggish in its movements.”  Soon after he continues, “These hideous reptiles may oftentimes be seen on the black rocks, a few feet above the surf, basking in the sun with outstretched legs.” 

Not only was the marine iguana’s appearance offensive to Darwin, so was its behavior. “One day I carried one to a deep pool left by the retiring tide, and threw it in several times as far as I was able. It invariably returned in a direct line to the spot where I stood.”

Darwin, however, limited his disdain. “The meat of these animals when cooked is white, and by those whose stomachs rise above all prejudices, it is relished as very good food.”

In 1959 the Galapagos Islands became an Ecuadorian National Park, so no more iguana tossing or munching, but the lizards have remained intriguing. A group of modern-day ecologists have studied them and discovered an unexpected survival feature—the marine iguanas’ bodies shorten and lengthen repeatedly over years according to el Niño/la Niña climate oscillations.

When times are good and the algae on which they feed is plentiful, the marine iguanas grow longer. When their principal food source is scarce, their bodies shorten by up to 20% of their length. (That is comparable to average height humans losing a foot in stature and then springing back to their baseline height repeatedly according to dietary intake.)  In 2000, the investigators published their results in Nature, a leading scientific journal. They noted that the marine iguanas’ cartilage and fibrous tissue could account for no more than half the shift, which led them to the only plausible conclusion: the bones shrink.

In 2019, another group of ecologists published an article about shrews (mammalian mice-like critters). The scientists reported that from the shrews’ first summer to the end of their first winter, their brain cases (skulls) size shrank by 13% and then enlarged by 10% the following summer. The researchers speculated that this phenomenon saved energy, which allowed the shrews to successfully mate in their second summer.

Across zoology, regulation of skeletal size varies by animal class. Birds and mammals grow to a certain size and then stop. Fish, frogs, and reptiles, however, never completely stop growing. Humans do get shorter in old age because the cushion-like cartilage discs between our vertebrae flatten, but the bones themselves do not shrink.

Shrews and marine iguanas are therefore apparently unique in their ability to change the length of their bones, and for the latter, repeatedly. I say apparently for two reasons. Other animals could possibly do the same but have not yet fallen between the tips of an ecologist’s measuring callipers. More importantly, however, the reported observations fly in the face of what bone biologists know about how bones grow, mature, and age.  

Whereas ecologists include in their queries the interplay of animals and their surroundings, bone biologists scrutinize the cellular and molecular nature of bone formation and maintenance. For a bone to shrink, specialized bone-dissolving cells on its surface would have to remove material. Simultaneously bone-forming cells in the hollow interior would have to add substance, otherwise the bone would disappear. Then when it came time for the bone to enlarge, the opposite inside-outside activity would have to occur. Nobody has observed anything of this sort.

After both groups of ecologists reported their findings, they moved on to other environmental inquiries. Other scientists have not challenged or extended the original findings. This is understandable because the task would be problematic. For laboratory-housed shrews, a careful multidisciplinary analysis would be possible; but because the shrews naturally die during their second summer, they would not afford investigators the opportunity to follow the changes through more than one cycle.   For marine iguanas, the investigation would be herculean. It would require stumbling across rough volcanic boulders far out in the Pacific Ocean, catching, tagging, and measuring hundreds of specimens, drawing their blood for detailed high-tech analyses, studying radiographic images and biopsies of their vertebrae, and then repeating the process at several year intervals over the animals’ nearly 30-year life spans. Complicating the study further, 90% of marine iguanas may die of starvation due to climate oscillations expected over a decades-long study.

10 second video. Watch one walk.

This chasm between what the ecologists know about how environmental changes affect skeletal size and what bone biologists understand about bone formation and growth is deep. The gap highlights an aspirational principle in the design of scientific research—cross-fertilization among specialties brings multiple viewpoints to bear and likely yields deeper insights. For the present conundrum, the ecologists have one set of facts, the bone biologists have another. They should talk. Discovery and control of the involved molecular and cellular mechanisms could hold great promise for preventing and treating both weak and short bones.

Does such research sound intriguing? I think so. I’d be willing to sign on as a cook for the Galapagos expedition; but sorry, Charles, no more iguana stew.

Coming June 2023: a companion book all about muscle

Museum Hopping in Quito

While on my way to the Galapagos Islands, I spent a day museum hopping in Quito. I wanted to learn more about pre-Columbian cultures and, of course, about how native people in the region incorporated repurposed bones into their lives. I had previously hit jackpots visiting North American and European museums and discovered the myriad ways indigenous people have crafted bone into objects of great utility, beauty, or both. In Quito, however, I came away disappointed yet enlightened.

Two archeology museums were tucked away on university campuses and were hard to find. In broken Spanish, I asked a group of students for directions, and one instantly replied, “Would you prefer English?” Several times locals walked blocks with me to ensure that I found my destination. Those experiences by themselves were enlightening.

I visited four museums that housed anthropological artifacts from various pre-Columbian Ecuadorian cultures. Ceramic vessels and figures abounded. There were some examples of metal and beadwork, but alas, a scarcity of bones—an awl here, a funerary urn containing a revered ancestor’s bones there.

After interspersing visits to the Botanical Gardens and Natural History Museum for variety, I finished my museum marathon at the Casa del Alabado Museum of Pre-Columbian Art. It is entirely unassuming from the street, so much so that I obliviously walked past its entrance the first time. But a block later when I realized that I had gone too far, it dawned on me that the Casa was likely the one with the armed guard positioned in the doorway. Inside, the museum was indeed worth protecting. Several tranquil and adjoining courtyards with overlooking balconies were surrounded by room after room of incredibly beautiful ceramic objects, all artfully displayed and carefully lit. In many rooms I was the only visitor, which added to the chapel-like atmosphere.

I found only two items made from bone, a stick pin and a fist-ended flute, likely carved from a human forearm bone.

When I first entered the museum, both youngish people at the front desk immediately distinguished themselves as far more than ticket takers and took pains to show me the detailed guidebook (in English) and explain the layout of the collection. Later, one walked with me so I could point out a piece that I was uncertain about. Was bone or ceramic and what was its purpose? She knew the answers. Then back at the entrance, I commented to them about the abundance of ceramics and the dearth of bone artifacts that I had seen over the day and that this mix differed marked from anthropological collections I had seen on other continents. They had different answers, each was revealing.

One noted that much of the soil in Ecuador is moist and volcanic, i.e., highly acidic, and therefore conducive to dissolving bone. (I had forgotten, but I received the same answer to a similar question in Japan, which is also mostly volcanic in origin.) The other observed that once people perfected the art of turning clay into ceramic, why would they bother working with any lesser crafting material? They also had plenty of fuel to heat their kilns. By contrast, imagine the Inuits trying to fire clay objects with seal blubber.

Overall, it was a great day. If you have an opportunity to visit Quito, plan to see some of the museums, especially the Museo Casa del Alabado. Then step outside and look up. On a clear day, the ice-capped Cotopaxi (19,347 feet) will remind you not to search too hard for old bones in volcanic soil.