Thursday, September 18, 2008
neanderthals 9
Evolutionary biologist Clive Finlayson, of the Gibraltar Museum, was standing in the vestibule of Gorham's Cave, a magnificent tabernacle of limestone opening to the sea on the Rock of Gibraltar. Inside, fantastic excretions of flowstone drooled from the ceiling of the massive nave. The stratigraphy in the cave is pocked with evidence of Neanderthal occupation going back 125,000 years, including stone spearpoints and scrapers, charred pine nuts, and the remains of ancient hearths. Two years ago, Finlayson and his colleagues used radiocarbon dating to determine that the embers in some of those fireplaces died out only 28,000 years ago—the last known trace of Neanderthals on Earth. (Other hearths in the cave may be as young as 24,000 years old, but their dating is controversial.)
From pollen and animal remains, Finlayson has reconstructed what the environment was like from 50,000 to 30,000 years ago. Back then, a narrow coastal shelf surrounded Gibraltar, the Mediterranean two or three miles distant. The landscape was scrub savanna scented with rosemary and thyme, its rolling sand dunes interrupted by the occasional cork oak and stone pine, with wild asparagus growing in the coastal flats. Prehistoric vultures, some with nine-foot wingspans, nested high up in the cliff face, scanning the dunes for meals. Finlayson imagines the Neanderthals watching the birds circle and descend, then racing them for food. Their diet was certainly more varied than the typical Neanderthal dependence on terrestrial game. His research team has found rabbit bones, tortoise shells, and mussels in the cave, along with dolphin bones and a seal skeleton with cut marks. "Except for rice, you've almost got a Mousterian paella!" Finlayson joked.
But then things changed. When the coldest fingers of the Ice Age finally reached southern Iberia in a series of abrupt fluctuations between 30,000 and 23,000 years ago, the landscape was transformed into a semiarid steppe. On this more open playing field, perhaps the tall, gracile modern humans moving into the region with projectile spears gained the advantage over the stumpy, muscle-bound Neanderthals. But Finlayson argues that it was not so much the arrival of modern humans as the dramatic shifts in climate that pushed the Iberian Neanderthals to the brink. "A three-year period of intense cold, or a landslide, when you're down to ten people, could be enough," he said. "Once you reach a certain level, you're the living dead."
The larger point may be that the demise of the Neanderthals is not a sprawling yet coherent paleoanthropological novel; rather, it is a collection of related, but unique, short stories of extinction. "Why did the Neanderthals disappear in Mongolia?" Stringer asked. "Why did they disappear in Israel? Why did they disappear in Italy, in Gibraltar, in Britain? Well, the answer could be different in different places, because it probably happened at different times. So we're talking about a large range, and a disappearance and retreat at different times, with pockets of Neanderthals no doubt surviving in different places at different times. Gibraltar is certainly one of their last outposts. It could be the last, but we don't know for sure."
Whatever happened, the denouement of all these stories had a signatory in Gorham's Cave. In a deep recess of the cavern, not far from that last Neanderthal hearth, Finlayson's team recently discovered several red handprints on the wall, a sign that modern humans had arrived in Gibraltar. Preliminary analysis of the pigments dates the handprints between 20,300 and 19,500 years ago. "It's like they were saying, Hey, it's a new world now," said Finlayson.j
From pollen and animal remains, Finlayson has reconstructed what the environment was like from 50,000 to 30,000 years ago. Back then, a narrow coastal shelf surrounded Gibraltar, the Mediterranean two or three miles distant. The landscape was scrub savanna scented with rosemary and thyme, its rolling sand dunes interrupted by the occasional cork oak and stone pine, with wild asparagus growing in the coastal flats. Prehistoric vultures, some with nine-foot wingspans, nested high up in the cliff face, scanning the dunes for meals. Finlayson imagines the Neanderthals watching the birds circle and descend, then racing them for food. Their diet was certainly more varied than the typical Neanderthal dependence on terrestrial game. His research team has found rabbit bones, tortoise shells, and mussels in the cave, along with dolphin bones and a seal skeleton with cut marks. "Except for rice, you've almost got a Mousterian paella!" Finlayson joked.
But then things changed. When the coldest fingers of the Ice Age finally reached southern Iberia in a series of abrupt fluctuations between 30,000 and 23,000 years ago, the landscape was transformed into a semiarid steppe. On this more open playing field, perhaps the tall, gracile modern humans moving into the region with projectile spears gained the advantage over the stumpy, muscle-bound Neanderthals. But Finlayson argues that it was not so much the arrival of modern humans as the dramatic shifts in climate that pushed the Iberian Neanderthals to the brink. "A three-year period of intense cold, or a landslide, when you're down to ten people, could be enough," he said. "Once you reach a certain level, you're the living dead."
The larger point may be that the demise of the Neanderthals is not a sprawling yet coherent paleoanthropological novel; rather, it is a collection of related, but unique, short stories of extinction. "Why did the Neanderthals disappear in Mongolia?" Stringer asked. "Why did they disappear in Israel? Why did they disappear in Italy, in Gibraltar, in Britain? Well, the answer could be different in different places, because it probably happened at different times. So we're talking about a large range, and a disappearance and retreat at different times, with pockets of Neanderthals no doubt surviving in different places at different times. Gibraltar is certainly one of their last outposts. It could be the last, but we don't know for sure."
Whatever happened, the denouement of all these stories had a signatory in Gorham's Cave. In a deep recess of the cavern, not far from that last Neanderthal hearth, Finlayson's team recently discovered several red handprints on the wall, a sign that modern humans had arrived in Gibraltar. Preliminary analysis of the pigments dates the handprints between 20,300 and 19,500 years ago. "It's like they were saying, Hey, it's a new world now," said Finlayson.j
# posted by roodbont @ 2:49 PM 
