April 2011, Daily News

Caves in Spain Yielding More Early Human Finds

By Dan McLerran   Mon, May 09, 2011

It is a tale of two caves. Each has a story to tell about ancient human occupants who scratched a living out of Ice Age Europe. They may have lived in one of these caves as long ago as 900,000 years B.P. (before the present era). Scientists in southeastern Spain have been methodically piecing together the stories in these caves through careful excavation and analysis of finds that may significantly expand our knowledge of early humans and how they lived in what is today southern Europe. What is more, their finds may help fill in an important chapter in human evolution.  

Sima de las Palomas ("Dove Hill") is a natural rock shaft about 75 meters above sea level in the side of a hill that rises abruptly above a flat coastal plain not far from the Mediterranean coast in Murcia Province, Spain. During the Pleistocene Epoch (2,588,000 - 12,000 years B.P.), the shaft cave filled with a sediment of soil, rocks, plant, and animal remains, hardening over thousands of years into a conglomerate geologists and archaeologists call "breccia". It turned out that the breccia was also rich in fossils and Paleolithic artifacts, as a local conservationist soon discovered when he recovered the fossilized remains of a human jaw while rappelling down the side of the shaft in 1991. Notified of the discovery, archaeologists, led by Michael Walker of the University of Murcia, began systematically excavating the cave shaft in 1994, beginning with the upper layers of the breccia fill (dated to 35,000 - 60,000 years B.P. -- the Ice Age) and working down. Since then, they have uncovered fossil remains of panthers or lions, wild horse, deer, ibex, hyaenas, hippopotamus, elephants, rhinoceros, aurochs, tortoise, and a variety of bird species. Analysis of pollen samples suggested mild, moist conditions. This was not a typical picture of an Ice Age climate. The research team concludes that it was "perhaps an interstadial [period] during the last Ice Age".*

More significantly, they have uncovered Paleolithic artifacts -- Mousterian stone tools that included an assemblage of scrapers, flat triangular projectile points, awls, hammerstones and flakes, among others. This was the signature industry of Homo neanderthalensis, or Neanderthals. Associated with them are, to date, a total of 150 fossilized bones and teeth, most of them from the upper levels of the breccia and others from the rubble left by iron miners who had excavated at the site a hundred years ago. Most of the remains have been identified as those of Homo neanderthalensis, but some, particularly among the group excavated from the rubble, exhibited features (not conclusively) more attributable to a much older species -- that of Homo heidelbergensis, a species that lived between 600,000 and 400,000 years ago and theorized by many scholars to be the fore-runners, or ancestral species to, the Neanderthals. The Neanderthal finds represented at least 9 individuals in all, from infants to adults. 

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Artist reconstruction of a Neanderthal. Courtesy Stefan Scheer. Wikimedia Commons.

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But the most striking finds of the shaft revolve around the discovery of articulated skeletons of three Neanderthal individuals. Dated to about 50,000 years B.P., the finds included skulls with mandibles, shoulder blades, vertebral column, rib cages, upper limbs, pelvis, lower limbs, hands and feet, anatomically connected and positioned in a manner similar to that found at other Neanderthal sites identified or interpreted by archaeologists as likely burial grounds. Recovered along with them were burnt bones of large mammals and Mousterian implements. The skeletons were covered in stones in a manner thought to be intentional. Had they discovered a Neanderthal burial? Was the shaft cave a place for burial of the deceased? Much more work is ahead before a more complete story can be written about the findings at Sima de las Palomas.

Cueva Negra ("Black Cave"), unlike Sima de las Palomas, lies further inland from the coast, about 100 kilometers from Sima. It is a cliff-side rockshelter situated about 750 meters above sea level and 40 meters above the river Quipar. Located in a highland area at the foot of a range of mountains that peak to 2,000 meters, its environment is very different from that of Sima. During the Ice Age, its surrounding environment was not habitable by humans for much of the year. Like Sima, it has also been filled with sediment over thousands of years. But in contrast to Sima, its sediments reach much farther back in time. Using a variety of state-of-the-art dating techniques, scientists have now dated the sediments to a time period as far back as 900,000 years B.P.

Systematic excavations began in earnest at the site in 1990. Since then, ongoing excavations have revealed the ancient (Pleistocene) presence of a variety of large mammals, such as elephant, rhinoceros, hyaena, wild horse, giant deer, aurochs, bison, and ibex, along with a wide variety of smaller mammals and birds, including waterfowl. The presence of waterfowl, along with pollen analysis that suggested the presence of water-loving vegetation in the area, indicated that the environment surrounding the rockshelter included a number of long-vanished Middle-Pleistocene lakes.

The big story at Cueva Negra, however, centers on the human finds and their newly dated context. The finds include hominid fossil remains, including six teeth, and Paleolithic artifacts of Acheulean bifacial core tools such as a hand-axe (a stone tool associated commonly with Home erectus and Homo heidelbergensis) and stone flakes that were produced using the Levalloisian technique, a production methodology applied by early humans during the entire Paleolithic period but more commonly in the Mousterian stone-work industry of the Neanderthals during the Middle Paleolithic. 

"We know now that the sediments in the cave were laid down long, long before the last ice age, and that it's Paleolithic "Levalloisian" chert flakes, some of which have edges modified by "Mousterian" retouch are among the oldest of this kind not only in Europe but even in Africa, and are accompanied by an "Acheulian" hand-axe on a stone cobble," reports Michael Walker.  "The entire 5-meter deep block of sediment in the cave belongs to the end of the early Early Pleistocene ( 2,588,000-781,000years ago) according to new optical sediment luminescence dating carried out at Oxford University in 2007 which points to an age of 650,000-900,000 years ago; and paleomagnetic research undertaken at the Berkeley Geochronology Center which points to an age no later than 780,000 years ago; and paleontological and paleopalynological research which suggest an age of about 900,000 years ago as very likely. This early date means that Cueva Negra's six early Neanderthal-size teeth are best seen as belonging to the Neanderthal precursor in Europe called Homo heidelbergensis".* 

Above, Right: Drawings of typical Acheulean handaxes, a common tool form produced by early humans such as Homo erectus and Homo heidelbergensis. 

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Fossil skull of Homo heidelbergensis. Courtesy Ryan Somma. Creative Commons.

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Aside from the value that each excavation will bring to understanding humans in Pleistocene Europe, however, is the additional knowledge that will accrue from the comparative study of human behavior at each location. Simultaneous research of the sites offers a unique opportunity to compare and contrast.  Says Walker, "The Project is allowing full recovery of these materials to be used to draw comparisons and contrasts between findings at the site of Sima de las Palomas near the coast and those at the site in the inland hill country of Cueva Negra.  This throws much-needed light on the exploitation of natural resources by Neanderthal folk (H. neandertalensis) and their even more archaic fore-runners (H. heidelbergensis) in two very different local environments 100 kilometers apart."*    

* The Project website at www.um.es/antropfisica/  

Top Cover Photo: Artist reconstruction of Homo neanderthalensis. Courtesy Erix! Creative Commons. 

By Dan McLerran

As Founder and Editor of Popular Archaeology Magazine, Dan is a freelance writer and journalist specializing in archaeology.  He studied anthropology and archaeology in undergraduate and graduate school and has been an active participant on archaeological excavations in the U.S. and abroad.  He is the creator and administrator of Archaeological Digs, a popular weblog about archaeological excavation and field school opportunities.