Thursday, December 6, 2012

Stone Spear Tips Surprisingly Old in Ancient Rome

Stone Spear Tips Surprisingly Old—"Like Finding iPods in Ancient Rome"

Some of our early human ancestors may have been smarter, and deadlier, than we thought, according to a new study of what may be Earth's oldest stone spear points. If the dating is correct, it suggests our evolutionary forebears mastered the art of the stone-tipped spear half a million years ago—some 250,000 years earlier than previously thought.

Discovering that the world's oldest known spear points may come from a Homo heidelbergensis site is "like finding an iPod in a Roman Empire site," said paleoanthropologist John Shea, who wasn't part of the study. "It's that level of weirdness." But it isn't weird to imagine these stocky big-game hunters using stone tools or even wooden spears in what's now South Africa. Until now, though, there's been no evidence H. heidelbergensis had the know-how to put the two together. To fasten a handle to a blade—a technique called hafting—a prehistoric hunter likely would have had to procure a stone blade, a wooden shaft, twine woven from plants or animal sinew, and glue made from tree resin. The glue itself may have required a mastery of fire, to liquefy the resin, said Shea, of New York's Stony Brook University. Tip of the Tongue Hafting would have been worth the work, because once you add a stone blade, a spear is "going to cause a lot more damage, create more bleeding, and cause the animal to die quicker," said University of Toronto anthropologist Jayne Wilkins, lead author of the new spear-tip study, released Thursday by the journal Science. By allowing more efficient hunting, Wilkins explained, the spear "means more reliable and regular access to meat." And scientists agree that more meat in the diet meant increased human brain size. That's not just an increase in brain tissue, she added. The increase in size hints at intellectual expansion. The hafting process requires forethought. "You have to plan days in advance before actually being able to use your weapons to hunt," she said. And you'd want to teach your comrades to do the same, presumably by talking. For Stony Brook's Shea, there's "no question" that hafting involved speech. "It would probably not be something that could be taught by imitation. This is a technology that is so complex that it absolutely, positively requires language." The idea that H. heidelbergensis may have had language may not be especially shocking, given that the species is theorized to be the last known common ancestor of both Neanderthals and our species, Homo sapiens. "We have language, and Neanderthals likely had language ... so it stands to reason that our last common ancestor had linguistic abilities too," Shea said. (See "Neanderthals Had Same 'Language Gene' as Modern Humans.") Proof of Concept Bearing telltale marks at their bases and impact fractures at their tips, the stones were unearthed in the 1980s at a Kalahari Desert site called Kathu Pan 1. But it wasn't until 2010, though, that scientists were able to date the sediments that had held the shaped stones. Even then "we didn't know what their function was," study leader Wilkins said. "Because, even though they look a lot like [later] points that were used as spear tips, they might also have been used for cutting and scraping. So we had to make sure they were actually spear tips." To do so, the team made copies of the Kathu Pan finds and jabbed them into a springbok carcass. Computer analysis later showed that both the prehistoric spear points and the replicas sustained similar damage. The technique is a "big leap forward," said Stony Brook's Shea, who praised the researchers for inventing a way to "measure the damage on the edges and compare it objectively and quantitatively to experimental pieces. "Now," he said, "nobody has an excuse for not doing that." Source from :

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