YouTube // Nature Video
YouTube // Nature Video

Did Lucy Die After Falling out of a Tree?

YouTube // Nature Video
YouTube // Nature Video

Not everything is like riding a bicycle; some skills in life are more of the use-it-or-lose-it variety. Researchers say Lucy may have died from a fall from a tree, possibly as a consequence of losing her ape ancestors’ tree-climbing skills. They published their controversial findings in the journal Nature.

The 3.2-million-year-old remains of an Australopithecus afarensis woman nicknamed Lucy have captivated the world since their discovery in Ethiopia in 1974. Her remains revealed to us the first human ancestors to have walked upright. In 2006, to fan the flames of Lucy’s fame, the Ethiopian government scheduled a tour for Lucy (also known as AL 288-1 and Dinknesh) with as many as 10 museum stops along the way. Many archaeologists feared that travel would cause irreparable damage to the one-of-a-kind skeleton. But the tour went on. During Lucy’s stop at the University of Texas, researchers pounced on the opportunity to put her bones in an x-ray computed tomography (CT) scanner.

Lucy’s distal radius undergoes computed tomographic scanning. Image credit: Marsha Miller, UT Austin

Using the scanner, the team produced 35,000 high-resolution “slices” of Lucy’s remains, which then allowed them to create a true-to-life 3D rendering that would stick around even after Lucy left.

Paleoanthropologist and project leader John Kappelman was examining the rendering when he saw something unusual: a strange break in Lucy’s right humerus (upper arm bone). In comparing the prehistoric injury to images of modern bone breakage, he realized it looked an awful lot like a four-part proximal humeral fracture, in which a blow to the shoulder blade smashes down the head of the humerus, compressing it into the shaft of the bone. Today, this kind of injury is common in car accidents when people have used their hands to brace against the dashboard, but it’s also typical in falls from great heights.

Kappelman and his colleagues then used a 3D printer to create a hard copy of the bones. They brought the newly made remains to nine orthopedic specialists, who all agreed with Kappelman’s initial assessment of a four-part proximal fracture. They suggest her injuries are consistent with someone who had fallen from a height of approximately 45 feet—about as high in the trees as chimpanzees typically build their sleeping nests—at a speed of about 37 mph.

“It may well have been the case that adaptations that permitted her to live more efficiently on the ground compromised her ability to move safely in the trees—and may have predisposed her kind to more falls,” Kappelman told Science.

Not everyone is convinced. Other archaeologists argue that other parts of Lucy’s body were far more fractured than they would have been after a fall. Of her shattered ribs, Kent State University biological anthropologist Owen Lovejoy said in Science, “you couldn’t do that with a shotgun blast.”

Then there’s the fact that Lucy’s bones could easily have been damaged after she died. Paleoanthropologist Don Johanson of Arizona State University, who discovered Lucy in 1974, is skeptical. “Terrestrial animals like antelopes and gazelles, elephants and rhinos and giraffes—all these bones show very similar fracture and breakage patterns as Lucy,” he pointed out to Science. “You can be sure they didn’t fall out of trees.”

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'Lime Disease' Could Give You a Nasty Rash This Summer
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iStock

A cold Corona or virgin margarita is best enjoyed by the pool, but watch where you’re squeezing those limes. As Slate illustrates in a new video, there’s a lesser-known “lime disease,” and it can give you a nasty skin rash if you’re not careful.

When lime juice comes into contact with your skin and is then exposed to UV rays, it can cause a chemical reaction that results in phytophotodermatitis. It looks a little like a poison ivy reaction or sun poisoning, and some of the symptoms include redness, blistering, and inflammation. It’s the same reaction caused by a corrosive sap on the giant hogweed, an invasive weed that’s spreading throughout the U.S.

"Lime disease" may sound random, but it’s a lot more common than you might think. Dermatologist Barry D. Goldman tells Slate he sees cases of the skin condition almost daily in the summer. Some people have even reported receiving second-degree burns as a result of the citric acid from lime juice. According to the Mayo Clinic, the chemical that causes phytophotodermatitis can also be found in wild parsnip, wild dill, wild parsley, buttercups, and other citrus fruits.

To play it safe, keep your limes confined to the great indoors or wash your hands with soap after handling the fruit. You can learn more about phytophotodermatitis by checking out Slate’s video below.

[h/t Slate]

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Why Eating From a Smaller Plate Might Not Be an Effective Dieting Trick 
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iStock

It might be time to rewrite the diet books. Israeli psychologists have cast doubt on the widespread belief that eating from smaller plates helps you control food portions and feel fuller, Scientific American reports.

Past studies have shown that this mind trick, called the Delboeuf illusion, influences the amount of food that people eat. In one 2012 study, participants who were given larger bowls ended up eating more soup overall than those given smaller bowls.

However, researchers from Ben-Gurion University in Negev, Israel, concluded in a study published in the journal Appetite that the effectiveness of the illusion depends on how empty your stomach is. The team of scientists studied two groups of participants: one that ate three hours before the experiment, and another that ate one hour prior. When participants were shown images of pizzas on serving trays of varying sizes, the group that hadn’t eaten in several hours was more accurate in assessing the size of pizzas. In other words, the hungrier they were, the less likely they were to be fooled by the different trays.

However, both groups were equally tricked by the illusion when they were asked to estimate the size of non-food objects, such as black circles inside of white circles and hubcaps within tires. Researchers say this demonstrates that motivational factors, like appetite, affects how we perceive food. The findings also dovetail with the results of an earlier study, which concluded that overweight people are less likely to fall for the illusion than people of a normal weight.

So go ahead and get a large plate every now and then. At the very least, it may save you a second trip to the buffet table.

[h/t Scientific American]

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