Spanish Archaeologists Discover Earliest Evidence of Woodworking
Microscopic wood particles on 1.5 million-year-old stone tools demonstrate that early humans had woodworking technology.
There is a consensus among many anthropologists that early humans, or Homo erectus, that lived in the African savannas between 2 and 1.5 million years ago were mainly scavenging creatures that lacked the intelligence and technology to hunt animals. However, a recent discovery in the Peninj region, west of Lake Natron, Tanzania, demonstrates a much higher level of technological sophistication during this period than previously believed.
A team of Spanish archaeologists, led by Dr. Manuel Dominguez-Rodrigo, from the Complutense University of Madrid, found residues of wood on the working edges of stone handaxes found in the region. The stone tools also show clear damage due to having been used in heavy-duty activities. These important findings push the appearance of human woodworking back by 1 million years, and will be reported in the April/May issue of the Journal of Human Evolution.
"This is the oldest evidence of woodworking in human evolution," said Dominguez-Rodrigo. "The remains belonging to Acacia trees are proof that early humans had wooden utensils, such as spears and digging sticks, which very likely enabled them to have the technology necessary to become successful hunters."
Other team members involved in the discovery include Prof. Jordi Juan-Treserres, a paleobotanist from University of Barcelona, Prof. Jordi Serrallonga, an archaeologist from University of Barcelona, Dr. Luis Alcala, paleontologist and vice-director of the Natural History Museum in Madrid, and Dr. Luis Luque, geologist from the Natural History Museum. Funding for the project has been through the Spanish Ministry of Culture, the Complutense University, and Earthwatch Institute.
The emergence of complex stone tools around 1.5 million years ago, with the so-called Acheulian technology, shows that early humans were endowed with a sophisticated dexterity in crafting some tools. However, these large bifacial artifacts, among which handaxes are the most common, were inefficient hunting weapons. Archaeological remains in early sites show that these early humans used the stone tools to butcher animals. For most archaeologists the lack of other artifacts suggests the lack of the adequate technology for a hunting way of life, until now.
The area of Peninj contains some of the oldest archaeological sites in the world with Acheulian tools. Most of the fossil fauna discovered by the Spanish team belong to animals that suggest a very open and dry savanna environment. Equids (like modern zebras), antilopini (like modern gazelles) and alcelaphini (like modern wildebeest) constitute most of the animals discovered. The fossil pollen discovered also indicates a very open landscape dominated by grasslands and a smaller number of trees among which Acacia is the best represented. Some plant residues discovered (called phytoliths) show that the type of grass most represented is a short grass that grows in very open and dry ecosystems.
Peninj exhibits the most open paeleolandscape of all the areas where archaeological sites dated to 2-1.5 million years have been discovered so far. This means that the availability of vegetable resources must have been very limited for early humans here. It also means that the availability of scavengeable resources must have been fairly small, since open landscapes are always full with competing carnivores.
Dominguez-Rodrigo suggests that Peninj provides a unique scenario to test some of the most relevant hypotheses on human evolution. His team is attempting to answer questions such as: How did early humans survive in such a harsh environment? Did they hunt or did they scavenge for survival? If these hominids hunted, making them the earliest hunters in human history, what did their technology consists of? By studying the technology of these early humans, the team hopes to get a glimpse on how intelligent they were.
On-going studies in Peninj show that a strong competition of carnivores in the area must have prevented early humans from obtaining animal protein resources through scavenging. On the contrary, the analyses of bones from the archaeological sites show that hominids were exploiting fully-fleshed animal carcasses. This is indicated by the amount of cut marks made with stone tools on anatomical sections where flesh is nonexistent if carnivores had consumed the animals before hominids did. This fact suggest that early humans were hunting these animals unearthed at Peninj. Domingues-Rodrigo's team is attempting to find out how.
One of the archaeological sites in Peninj has provided the team with a critical part of the answer. An assemblage of over 200 stone tools has been excavated in a nicely preserved context. This has allowed for the first time the discovery of well-preserved microscopic remains on the edges of the tools caused by their use for 1.5 million years ago. The team has carefully analyzed the artifacts and the surrounding soil for plant residues. Plant residues belonging to grasses have been found in the soil, but the residues found on the artifacts are different. They appear only on the surface of the edges of the handaxes, which are worn by hard use. The microscopic plant remains found on the handaxes have been identified as belonging to Acacia trees, indicating that the hominids were chopping wood.
The meaning of this discovery is very relevant for the study of human evolution: humans were involved in woodworking activities more than a million years before the oldest evidence that we had until now. Early humans, at a very early stage of their evolution, were producing wooden implements that have not been preserved in the archaeological record. According to this discovery, rudimentary spears could have been one type of wooden artifacts that humans were making 1.5 million years ago. This could have enhanced their adaptation as hunters to open environments, and gives us a further insight into the complex intelligence of hominids at that time.
"The discovery of early woodworking technology shows that human intelligence at its beginnings was far more complex than accepted so far," said Dominguez-Rodrigo. "It also shows that early humans were active agents in the modification of the environment, instead of passive animals like the rest of the fauna as they were pictured until now."
Earthwatch volunteers working with Dr. Dominguez-Rodrigo last year helped expand on the team's findings in Peninj, further refining the analysis of this important find.
Earthwatch Institute is an international nonprofit organization which supports scientific field research worldwide by offering members of the public unique opportunities to work alongside leading field scientists and researchers. The Institute's mission is to engage people worldwide in scientific field research and education to promote the understanding and action necessary for a sustainable environment.