Is It True That T. Rex Could Only See Things That Were Moving?

Freer Law/iStock via Getty Images
Freer Law/iStock via Getty Images

I rewatched Jurassic Park a few weeks ago and, from the story to the special effects, it still holds up. But I’ve been nagged by one thing that’s stuck with me from the first time I saw the movie—a thing that has been ingrained in our collective knowledge and perception of dinosaurs: protagonist Alan Grant's assertion about what the Tyrannosaurus rex can and can’t see.

In the scene where the T. rex gets loose and attacks a group of human characters, Grant says to Lex, “Don’t move. It can’t see us if we don’t move.” Sure enough, the dinosaur gets up in their faces without noticing them right after he says that. For what it's worth, Michael Crichton does explain in the Jurassic Park novel that the amphibian DNA used to help bring the dinosaurs to life hobbled their visual cortices. Director Steven Spielberg and the movie's screenwriters dropped the ball big time here, importing the dinosaurs’ vision problems but not the explanation for them. Instead, in the movie, Grant comes off like he’s stating an accepted dino fact.

Sci-Fi versus Reality

He’s not. In the last few years, real-world paleontologists have proven Dr. Grant very wrong. In 2006, Kent Stevens from the University of Oregon did an experiment inspired by that very scene to figure out what sort of binocular range (the field of view both eyes can see simultaneously) T. rex might have had. The wider that range, the better an animal’s depth perception and capacity to distinguish objects that are motionless or camouflaged.

Stevens built a scale model of the T. rex’s head and popped in some taxidermic eyes based on the eyes of three animals pretty closely related to T. rex—alligators, ostriches, and eagles—and adapted for situations that a dinosaur would have likely encountered. As he explains on his website, he used a technique called “inverse perimetry” to estimate “whether a given probe would be visible, based on whether there is a clear, unobstructed view of the pupil along a line of sight,” and mapped the model’s field of view.

Stevens' model study suggests that T. rex had a binocular range of around 55°, better than that of modern-day hawks and eagles. And it would have only gotten better. Paleontologists know from the fossil record that, over millennia, T. rex’s eyes got larger and its snout got lower and narrower, giving it even clearer sight lines than Stevens’ model.

For more on dino-vision, see Stevens' web page and the study. For more on other JP mistakes that make dino geeks fume, see this Wikipedia list.

Why Do Fruitcakes Last So Long?

iStock
iStock

Fruitcake is a shelf-stable food unlike any other. One Ohio family has kept the same fruitcake uneaten (except for periodic taste tests) since it was baked in 1878. In Antarctica, a century-old fruitcake discovered in artifacts left by explorer Robert Falcon Scott’s 1910 expedition remains “almost edible,” according to the researchers who found it. So what is it that makes fruitcake so freakishly hardy?

It comes down to the ingredients. Fruitcake is notoriously dense. Unlike almost any other cake, it’s packed chock-full of already-preserved foods, like dried and candied nuts and fruit. All those dry ingredients don’t give microorganisms enough moisture to reproduce, as Ben Chapman, a food safety specialist at North Carolina State University, explained in 2014. That keeps bacteria from developing on the cake.

Oh, and the booze helps. A good fruitcake involves plenty of alcohol to help it stay shelf-stable for years on end. Immediately after a fruitcake cools, most bakers will wrap it in a cheesecloth soaked in liquor and store it in an airtight container. This keeps mold and yeast from developing on the surface. It also keeps the cake deliciously moist.

In fact, fruitcakes aren’t just capable of surviving unspoiled for months on end; some people contend they’re better that way. Fruitcake fans swear by the aging process, letting their cakes sit for months or even years at a stretch. Like what happens to a wine with age, this allows the tannins in the fruit to mellow, according to the Wisconsin bakery Swiss Colony, which has been selling fruitcakes since the 1960s. As it ages, it becomes even more flavorful, bringing out complex notes that a young fruitcake (or wine) lacks.

If you want your fruitcake to age gracefully, you’ll have to give it a little more hooch every once in a while. If you’re keeping it on the counter in advance of a holiday feast a few weeks away, the King Arthur Flour Company recommends unwrapping it and brushing it with whatever alcohol you’ve chosen (brandy and rum are popular choices) every few days. This is called “feeding” the cake, and should happen every week or so.

The aging process is built into our traditions around fruitcakes. In Great Britain, one wedding tradition calls for the bride and groom to save the top tier of a three-tier fruitcake to eat until the christening of the couple’s first child—presumably at least a year later, if not more.

Though true fruitcake aficionados argue over exactly how long you should be marinating your fruitcake in the fridge, The Spruce says that “it's generally recommended that soaked fruitcake should be consumed within two years.” Which isn't to say that the cake couldn’t last longer, as our century-old Antarctic fruitcake proves. Honestly, it would probably taste OK if you let it sit in brandy for a few days.

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What’s the Difference Between Crocheting and Knitting?

djedzura/iStock via Getty Images
djedzura/iStock via Getty Images

With blustery days officially upon us, the most pressing question about your sweaters, scarves, hats, and mittens is probably: “Are these keeping me warm?” If you’re a DIY enthusiast, or just a detail-oriented person in general, your next question might be: “Were these knitted or crocheted?”

Knitting and crocheting are both calming crafts that involve yarn, produce cozy garments and other items, and can even boost your mental well-being. Having said that, they do have a few specific differences.

To knit, you need needles. The size, material, and number of those needles depends on the project; though most traditional garments are made using two needles, it’s also possible to knit with just one needle, or as many as five. But regardless of the other variables, one or both ends of your knitting needles will always be pointed.

While crocheting calls for a similar long, thin tool that varies in size and material, it has a hooked end—and you only ever need one. According to The Spruce Crafts, even if you hear people refer to the tool as a crochet needle, they’re really talking about a crochet hook.

crotchet hook and garment
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Part of the reason you only use one hook brings us to the next difference between crocheting and knitting: When crocheting, there’s only one “active loop” on your hook at any given time, whereas knitting entails lining up loops down the length of your needles and passing them between needles. The blog Darn Good Yarn explains that since each loop is attached to a long row of stitches, accidentally “dropping” one off the end of your needle might unravel the entire row.

Of course, you have a better chance of avoiding that type of manual error if you’re using a knitting machine or loom, which both exist. Crocheting, on the other hand, has to be done by hand. Since machines can create garments with extremely small stitches, some knit clothes can be much more lightweight or close-fitting than anything you’d be able to crochet—and knitted clothes can also be mass-produced.

When it comes to what the items actually look like, crochet stitches characteristically look more like knots, while knit stitches seem flatter and less bulky. However, materials and techniques have come a long way over the years, and now there’s more crossover between what you’re able to knit and crochet. According to The Spruce Crafts, socks and T-shirts—traditionally both garments that would be knitted—can now technically be crocheted.

knitting needles and garment
Sedan504/iStock via Getty Images

And, believe it or not, knitting and crocheting can even be used to depict complicated mathematical concepts: see what a crocheted hyperbolic plane, Lorenz manifold, and more look like here.

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