CLOSE
A Neanderthal skull
A Neanderthal skull
Stephane De Sakutin, AFP/Getty Images

Scientists May Have Finally Figured Out Why We Have Eyebrows

A Neanderthal skull
A Neanderthal skull
Stephane De Sakutin, AFP/Getty Images

If you look at a pictures of some of the earlier branches of humanity's family tree, like Neanderthals or Homo erectus, you might notice that Homo sapiens got off relatively lightly, eyebrow-wise. Most early hominins had thick, bony brow ridges rather than the smooth brows of modern humans. For years, researchers have been arguing over why those thick ridges existed—and why modern humans evolved tinier brows. A new study suggests that heavy brow ridges had social usefulness that was more important than their physiological function.

Previous research has suggested that thick brow ridges helped connect early hominins' eye sockets with their brain cavities, or protected the skull from the physical stress put on it by chewing jaws, or even helped early hominins take punches to the face.

The new study by University of York researchers, published in the journal Nature Ecology & Evolution, used a digital model of a fossil skull, thought to be between 125,000 and 300,000 years old, of an extinct species called Homo heidelbergensis that evolved sometime between 300,000 and 600,000 years ago in what is now Zambia. The researchers manipulated the model, changing the size of the brow ridge and seeing what happened when they applied different bite pressures. They found that the brow ridge was much bigger than it needed to be if its purpose was just to connect the eye sockets with the brain case, and that it didn't seem to protect the skull from the force of biting.

Instead, the researchers suggest that the brow ridge played a social role. Other primates have similar brow ridges that serve a social purpose rather than a mechanical one, like male mandrills, whose colorful, heavy-browed muzzles serve as dominance displays. Heavy brow ridges may have played a similar role in early human species.

As Homo sapiens evolved, more subtle communication may have taken precedence over the permanent social signal of a giant brow ridge. As foreheads became more vertical, eyebrows could move more freely and subtly, leading to important social signals in modern humans, like expressions of surprise or indignation.

An accompanying analysis in the same journal, by Spanish paleontologist Markus Bastir, cautions that the results of the new study are appealing, but should be taken with a grain of salt. The specimen used for the digital model was missing a mandible, and the researchers subbed in a mandible from a Neanderthal, a related species but still a distinct one from Homo heidelbergensis. This may have altered the analysis of the model and bite stresses. Still, the study provides "exciting prospects for future research," he writes.

nextArticle.image_alt|e
A Neanderthal skull
iStock
arrow
Stones, Bones, and Wrecks
Researchers Accidentally Discover 128-Year-Old Shipwreck
iStock
iStock

Scientists conducting a routine survey of the waters along Australia's east coast got more than they bargained for when they accidentally discovered a 128-year-old shipwreck.

Their encounter with the sunken Carlisle, which sank in 1890, was captured on camera, and Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) has released footage showing an aerial view of the wreckage, teeming with schools of fish.

The researchers were mapping the seafloor of Bass Strait, which separates mainland Australia from the island of Tasmania, to improve nautical charts for the major shipping route, according to Mashable. During a scan of the waters, the sunken ship showed up as a "blip," ABC reports.

"We just happened to go over this blip, and we noticed it, and thought, 'Oh jeez, that looks just a little too much like a shipwreck,' and so we did a little bit more investigating and looked at it digitally," CSIRO hydrographer Matt Boyd told ABC. "Then once we established that yes, it was a shipwreck, we put a drop camera down."

Volunteers from the Maritime Archaeological Association of Victoria then went to the site and confirmed that the ship was indeed the Carlisle. It most likely collided with rocks while sailing from Melbourne to Newcastle, where it was supposed to pick up coal on its way to South America. All 23 crew members survived, escaping on three life boats.

The researchers discovered two more shipwrecks during a weeklong expedition from Brisbane to Hobart, one of which was identified as the HMAS Pioneer, a ship built for the British Royal Navy in 1900 that was scuttled in 1931.

[h/t ABC]

nextArticle.image_alt|e
A Neanderthal skull
iStock
arrow
Stones, Bones, and Wrecks
6 Priceless Treasures Lost in Shipwrecks
iStock
iStock

In the lore around treasures lost at sea, most of the excitement goes to pirate’s gold and the sunken luxuries of the Titanic. But in the centuries of human seafaring, many lesser-known priceless objects, from literary manuscripts to scientific research, have been claimed by the depths. Here are some tales of those losses, from a lifetime of work by a 19th-century woman who was an expert in cephalopods, to a rare book by Dickens that went down with the Lusitania.

1. LOUIS DE JAUCOURT'S ANATOMICAL LEXICON

Always, always, always back up your work. Of course, that's easier now than it was in the 18th century, when French scholar Louis de Jaucourt dispatched his six-volume Lexicon medicum universale to his Amsterdam publisher, a move intended to evade French censorship. The medical dictionary, on which he'd spent 20 years, was completely lost when the ship it was on sank off Holland's coast. Luckily, Jaucourt rebounded when Denis Diderot asked him to contribute to the Encyclopédie, now considered one of the greatest works of Enlightenment thought, for which he used his notes from the lost manuscript. Jaucourt became the publication's most prolific author, penning 40,000 articles—so many he was nicknamed l'esclave de l’Encyclopédie, or the "slave of the Encyclopedia."

2. THE FIELDWORK OF ALFRED RUSSEL WALLACE

Portrait of Alfred Russel Wallace, Welsh naturalist and explorer
Hulton Archive/Getty Images

In 1852, following four years of research in the Amazon, the British naturalist Alfred Russel Wallace was ready to return to England. He loaded his copious notes, animal and plant specimens, and drawings onto the brig Helen. Just 26 days into the voyage, the vessel caught fire. Wallace only had time to hastily fill a tin box with a few drawings of fish and palms and some scientific notes before joining the crew in the lifeboat. After 10 days marooned at sea, they were rescued by the brig Jordeson—but most of Wallace's work was gone forever. As he lamented in an October 19, 1852 letter, "The only things which I saved were my watch, my drawings of fishes, and a portion of my notes and journals. Most of my journals, notes on the habits of animals, and drawings of the transformations of insects, were lost.” While he continued as a leading naturalist—albeit one overshadowed in his evolution research by Charles Darwin—Wallace was never able to reconstruct those years of fieldwork.

3. THE CEPHALOPOD RESEARCH OF JEANNE VILLEPREUX-POWER

Before Jeanne Villepreux-Power’s 19th-century research, most scientists thought the Argonauta argo, or paper nautilus, scavenged its shell from other animals. But by inventing the modern aquarium, Villepreux-Power could study the species first-hand, and witness how it grows and repairs its own shell. The breakthrough was one of many discoveries made by the pioneer in cephalopod research, one of the few women to achieve prominence in Victorian science. She might be better known today if it weren't for the fact that when she and her husband decided to move from Sicily to London, the vessel on which they’d shipped their possessions—including the majority of her drawings, notes, and equipment—foundered off the coast of France in 1843. After the devastating loss, she never published again.

4. A COPY OF A CHRISTMAS CAROL OWNED BY CHARLES DICKENS

Sinking of the Lusitania
Three Lions/Getty Images

When Boston bookseller Charles Lauriat realized the RMS Lusitania was doomed that fateful day in 1915, he dashed to his cabin, using the light from a few matches to try to find the literary treasures he’d brought aboard. These included original drawings by Vanity Fair author William Makepeace Thackeray, as well as an edition of A Christmas Carol owned by Charles Dickens himself. The edition was irreplaceable, since it included Dickens’s notes related to his 1844 copyright suit against the illicit republishing of his story. In the book Dead Wake: The Last Crossing of the Lusitania, Erik Larson vividly describes Lauriat’s harrowing experience when the ocean liner was torpedoed by a German U-boat off the coast of Ireland: Lauriat grabbed the leather briefcase containing the Dickens, but left the Thackeray sketches behind. Rushing out to the deck, he saw a lifeboat packed with women and children that was being dragged down by the sinking ship. He jumped in with the briefcase, yet was unable to free the lifeboat, and in the escape into the water he lost the precious cargo. Out in the waves, he managed to evade entanglement with an antenna, swim to a collapsible lifeboat, and survive. One of the few items he managed to save were photographs of his baby, which he told his wife were his "mascot."

5. WRITINGS OF JOSÉ ASUNCIÓN SILVA

Portrait of José Asunción Silva

Many Colombians can recite the first lines from the influential Modernist poet José Asunción Silva's "Nocturne III"—"A night / A night full of hushings, of the curled wool of perfume / And incanting wing"—and it’s even printed in microtext on the 5000 Colombian peso bill. The poem, written in 1892, is believed to be a tribute to Silva’s half-sister. Silva suffered another blow in 1895, when many of his manuscripts, including a draft of a novel, were lost in a shipwreck. He left his diplomatic post in Venezuela, and dedicated all his time to reconstructing the drowned novel. But his melancholy continued: After visiting a doctor to ask the exact position of his heart, he shot himself in 1896. His rewritten novel—After-Dinner Conversation (De sobremesa) —wasn’t published until 1925.

6. THE ART OF GIOVANNI BATTISTA LUSIERI

The South-east Corner of the Parthenon, Athens by Giovanni Battista Lusieri
Giovanni Battista Lusieri, Wikimedia Commons // Public Domain

Giovanni Battista Lusieri was a meticulous painter of the Italian landscape, particularly its classical ruins. In large panoramas and more compact watercolors, he depicted the Acropolis, views of Rome and Naples, and, his favorite, the eruption of Mount Vesuvius. Some of his most striking works captured the volcano at night, illuminating the darkness with its orange glow. Lord Byron called him "an Italian painter of the first eminence." Yet his name is now obscure. This is partly due to the years he stopped painting to help Lord Elgin remove and ship the Parthenon Marbles to London. But when Lusieri's artwork was being sent home from Greece after his death in 1821, a shipwreck destroyed nearly half of it (including a spectacular 25-foot-long panorama of Athens), helping to ensure his fall from fame.

BONUS: PEKING MAN

A replica of the Peking Man Skull
A replica of the Peking Man Skull

When paleontologists discovered the bones of "Peking man" in a dig near Beijing in the 1920s, they were the oldest hominid fossils ever found. However, scientists can now only study the bones—thought to be about half a million years old—from casts. The Peking Man fossils were last seen in December 1941, but vanished during the Japanese occupation of China while they were being sent to the United States for safekeeping. There are many conjectures on their fate, from being secretly stored away in Japan, to being under a parking lot in China. Yet one enduring theory is that they were lost at sea on the Japanese freighter Awa Maru: In 1945, the ship was torpedoed in the Taiwan Strait by the USS Queenfish despite being guaranteed safe passage by the United States, leading to the loss of more than 2000 lives—and, it's said, the priceless Peking fossils [PDF].

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios