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ThinkStock/Erin McCarthy
ThinkStock/Erin McCarthy

Can We Determine the Sex of a Dinosaur?

ThinkStock/Erin McCarthy
ThinkStock/Erin McCarthy

On August 12, 1990, the most complete Tyrannosaurus rex skeleton ever discovered was unearthed in the badlands of South Dakota by paleontologists Peter Larson and Susan Hendrickson. The animal was nicknamed “Sue” in honor of the latter scientist and, after a lengthy legal battle, her remains were purchased for the hefty sum of $8.4 million by the Chicago Field Museum. Today, she's easily become the world's most famous dinosaur. But what if “Sue” wasn't actually a female?

“We'd given the T. rex that name and always referred to it as 'she' or 'her',” said Larson, “But even at the site, people were asking me 'What if she's a male?' I'd say that we could always point to that Johnny Cash song 'A Boy Named Sue.'”

Country classics notwithstanding, can paleontologists accurately determine the sex of a long-dead dinosaur?

The short answer is yes ... and no.

While Sue's gender remains very much in question, comparatively recent research has shown that at least some dinosaur specimens may be sexed with reasonable certainty by modern scientists. The riddle's solution may very well lie in the bones of present-day dinos—also known as “birds."

Producing eggs is a very taxing process for expectant avian mothers, as the calcium in their shells is biologically expensive to build. When eggs start forming in the womb of a gravid bird, her body releases a heightened level of estrogen. This triggers the growth of what's known as “medullary bone” inside of her hollow leg and arm bones. The specialized medullary bone tissue provides much-needed calcium for the growing eggshells and lingers until their completion, at which point it disappears.

In 2005, paleontologists at North Carolina State University and Montana State University announced that they'd discovered medullary tissue within the limb bones of a T. rex specimen, suggesting that the animal was A) female and B) gravid at the time of its death.

The approach is hardly fool-proof: Only the bones of pregnant female dinosaurs would show any sign of medullary tissue, rendering the technique useless for deducing the sex of the vast majority of dinosaur skeletons. Nevertheless, the findings have excited a number of paleontologists, including one international team which sought to deduce the link between gender and this tell-tale tissue in a group of well-preserved fossilized birds this past February.

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Big Questions
Are There Number 1 Pencils?
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Almost every syllabus, teacher, and standardized test points to the ubiquitous No. 2 pencil, but are there other choices out there?

Of course! Pencil makers manufacture No. 1, 2, 2.5, 3, and 4 pencils—and sometimes other intermediate numbers. The higher the number, the harder the core and lighter the markings. (No. 1 pencils produce darker markings, which are sometimes preferred by people working in publishing.)

The current style of production is profiled after pencils developed in 1794 by Nicolas-Jacques Conté. Before Conté, pencil hardness varied from location to location and maker to maker. The earliest pencils were made by filling a wood shaft with raw graphite, leading to the need for a trade-wide recognized method of production.

Conté’s method involved mixing powdered graphite with finely ground clay; that mixture was shaped into a long cylinder and then baked in an oven. The proportion of clay versus graphite added to a mixture determines the hardness of the lead. Although the method may be agreed upon, the way various companies categorize and label pencils isn't.

Today, many U.S.  companies use a numbering system for general-purpose, writing pencils that specifies how hard the lead is. For graphic and artist pencils and for companies outside the U.S., systems get a little complicated, using a combination of numbers and letters known as the HB Graphite Scale.

"H" indicates hardness and "B" indicates blackness. Lowest on the scale is 9H, indicating a pencil with extremely hard lead that produces a light mark. On the opposite end of the scale, 9B represents a pencil with extremely soft lead that produces a dark mark. ("F" also indicates a pencil that sharpens to a fine point.) The middle of the scale shows the letters and numbers that correspond to everyday writing utensils: B = No. 1 pencils, HB = No. 2, F = No. 2½, H = No. 3, and 2H = No. 4 (although exact conversions depend on the brand).

So why are testing centers such sticklers about using only No. 2 pencils? They cooperate better with technology because early machines used the electrical conductivity of the lead to read the pencil marks. Early scanning-and-scoring machines couldn't detect marks made by harder pencils, so No. 3 and No. 4 pencils usually resulted in erroneous results. Softer pencils like No. 1s smudge, so they're just impractical to use. So No. 2 pencils became the industry standard.

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Big Questions
What Are Curlers Yelling About?
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WANG ZHAO/AFP/Getty Images

Curling is a sport that prides itself on civility—in fact, one of its key tenets is known as the “Spirit of Curling,” a term that illustrates the respect that the athletes have for both their own teammates and their opponents. But if you’re one of the millions of people who get absorbed by the sport once every four years, you probably noticed one quirk that is decidedly uncivilized: the yelling.

Watch any curling match and you’ll hear skips—or captains—on both sides barking and shouting as the 42-pound stone rumbles down the ice. This isn’t trash talk; it’s strategy. And, of course, curlers have their own jargon, so while their screams won’t make a whole lot of sense to the uninitiated, they could decide whether or not a team will have a spot on the podium once these Olympics are over.

For instance, when you hear a skip shouting “Whoa!” it means he or she needs their teammates to stop sweeping. Shouting “Hard!” means the others need to start sweeping faster. If that’s still not getting the job done, yelling “Hurry hard!” will likely drive the point home: pick up the intensity and sweep with downward pressure. A "Clean!" yell means put a brush on the ice but apply no pressure. This will clear the ice so the stone can glide more easily.

There's no regulation for the shouts, though—curler Erika Brown says she shouts “Right off!” and “Whoa!” to get her teammates to stop sweeping. And when it's time for the team to start sweeping, you might hear "Yes!" or "Sweep!" or "Get on it!" The actual terminology isn't as important as how the phrase is shouted. Curling is a sport predicated on feel, and it’s often the volume and urgency in the skip’s voice (and what shade of red they’re turning) that’s the most important aspect of the shouting.

If you need any more reason to make curling your favorite winter sport, once all that yelling is over and a winner is declared, it's not uncommon for both teams to go out for a round of drinks afterwards (with the winners picking up the tab, obviously). Find out how you can pick up a brush and learn the ins and outs of curling with our beginner's guide.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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