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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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Why Can Parrots Talk and Other Birds Can't?
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If you've ever seen a pirate movie (or had the privilege of listening to this avian-fronted metal band), you're aware that parrots have the gift of human-sounding gab. Their brains—not their beaks—might be behind the birds' ability to produce mock-human voices, the Sci Show's latest video explains below.

While parrots do have articulate tongues, they also appear to be hardwired to mimic other species, and to create new vocalizations. The only other birds that are capable of vocal learning are hummingbirds and songbirds. While examining the brains of these avians, researchers noted that their brains contain clusters of neurons, which they've dubbed song nuclei. Since other birds don't possess song nuclei, they think that these structures probably play a key role in vocal learning.

Parrots might be better at mimicry than hummingbirds and songbirds thanks to a variation in these neurons: a special shell layer that surrounds each one. Birds with larger shell regions appear to be better at imitating other creatures, although it's still unclear why.

Learn more about parrot speech below (after you're done jamming out to Hatebeak).

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Prehistoric Ticks Once Drank Dinosaur Blood, Fossil Evidence Shows
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Ticks plagued the dinosaurs, too, as evidenced by a 99-million-year old parasite preserved inside a hunk of ancient amber. Entomologists who examined the Cretaceous period fossil noticed that the tiny arachnid was latched to a dinosaur feather—the first evidence that the bloodsuckers dined on dinos, according to The New York Times. These findings were recently published in the journal Nature Communications.

Ticks are one of the most common blood-feeding parasites. But experts didn’t know what they ate in prehistoric times, as parasites and their hosts are rarely found together in the fossil record. Scientists assumed they chowed down on early amphibians, reptiles, and mammals, according to NPR. They didn’t have hard evidence until study co-author David Grimaldi, an entomologist at the American Museum of History, and his colleagues spotted the tick while perusing a private collection of Myanmar amber.

A 99-million-year-old tick encased in amber, grasping a dinosaur feather.
Cornupalpatum burmanicum hard tick entangled in a feather. a Photograph of the Burmese amber piece (Bu JZC-F18) showing a semicomplete pennaceous feather. Scale bar, 5 mm. b Detail of the nymphal tick in dorsal view and barbs (inset in a). Scale bar, 1 mm. c Detail of the tick’s capitulum (mouthparts), showing palpi and hypostome with teeth (arrow). Scale bar, 0.1 mm. d Detail of a barb. Scale bar, 0.2 mm. e Drawing of the tick in dorsal view indicating the point of entanglement. Scale bar, 0.2 mm. f Detached barbule pennulum showing hooklets on one of its sides (arrow in a indicates its location but in the opposite side of the amber piece). Scale bar, 0.2 mm
Peñalver et al., Nature Communications

The tick is a nymph, meaning it was in the second stage of its short three-stage life cycle when it died. The dinosaur it fed on was a “nanoraptor,” or a tiny dino that was roughly the size of a hummingbird, Grimaldi told The Times. These creatures lived in tree nests, and sometimes met a sticky end after tumbling from their perches into hunks of gooey resin. But just because the nanoraptor lived in a nest didn’t mean it was a bird: Molecular dating pinpointed the specimen as being at least 25 million years older than modern-day avians.

In addition to ticks, dinosaurs likely also had to deal with another nest pest: skin beetles. Grimaldi’s team located several additional preserved ticks, and two were covered in the insect’s fine hairs. Skin beetles—which are still around today—are scavengers that live in aerial bird homes and consume molted feathers.

“These findings shed light on early tick evolution and ecology, and provide insights into the parasitic relationship between ticks and ancient relatives of birds, which persists today for modern birds,” researchers concluded in a news release.

[h/t The New York Times]

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