Prehistoric outdoor engravings
Dated: 28,000-21,000 BC
The Portuguese Côa Valley is the most extensive open air site of rock art in Europe.
Like a vast open air gallery, it features hundreds of stone panels with thousands of animal engravings and other forms of prehistoric art, dating back to the early Gravettian culture of the late Stone Age.
The valley contains the oldest art in Portugal and has become an important centre of Stone Age culture on the Iberian Peninsula.
It serves as an important reminder that not all rock art was made in caves - indeed, we may yet discover that cave art accounts for a minority of the total art produced during prehistory.
In addition, it's worth noting that discoveries of open air rock art in Europe, dating back to the Paleolithic, are relatively recent events.
The first discovery was in Mazouco (Portugal), in 1981. After this came Domingo García (Segovia, Spain), Piedras Blancas (Andalusia, Spain), Campôme and Fornols-Haut (both in the French Pyrenees), and Siega Verde (across the Spanish border).
The Côa River is a left-bank tributary of the Douro River, one of the major waterways that traverse the Iberian Mountains from east to west.
Its petroglyphs can be found in the last 17 kilometres of the Côa river valley up to where it joins the Douro.
The Côa Valley archaeological zone consists of 23 sites with prehistoric engravings or paintings, along the final stretch of the River Côa.
There are ten sites on the left bank and eight on the right bank. The remaining five sites are situated along other tributaries of the Douro River, at Faia, Quinta da Barca and Penacosa.
Out of the 23 sites, the following 14 are classified:
Since 1995, a team of scientists have been cataloguing the outdoor engraved drawings and paintings throughout the locality.
A museum and an archaeological park have also been established to inform visitors.
The whole project is supported by several different bodies, including: the Portuguese Ministry of Culture, the National Centre for Prehistoric Art, and the Portuguese Institute of Archaeology.
In 1998, UNESCO designated the 'Prehistoric Sites of the Côa Valley' a World Heritage Site.
In 2010, the Côa Valley World Heritage site was extended to include the open air engravings at Siega Verde (across the border in Spain), whose antiquity is on a par with Côa.
To see how Côa's engravings fit into the evolution of Paleolithic culture, see: Timeline of Prehistoric Art (from 540,000 BC).
The Côa Valley rock engravings were discovered in the early 1990s by Nelson Rebanda, a local archaeologist, just as the valley was due to be flooded as part of a major dam project.
The petroglyphs were identified as Paleolithic by archaeologist Mila Simoes de Abreu - a discovery which led ultimately to the cancellation of the dam.
In total, researchers discovered well over 5,000 outdoor engraved drawings of horses, bison, aurochs, deer, and other animals, as well as a few human figures, along with numerous abstract signs.
All of these artworks are situated outdoors, except for the parietal art in the Faia rock shelters.
In all, around 214 engraved panels have been discovered in 22 different groups.
Among the animals featured are aurochs, bison, deer, horses and ibex.
In addition, there are several images of fish, as well as a small group of geometric or abstract symbols (at Penascosa and Canada do Inferno), and one engraving of an anthropomorphic figure complete with phallus (at Ribeira de Piscos).
The dating of outdoor rock art is extremely difficult due to the long term effects of weather and the obvious likelihood of disturbance.
Cave art is much less prone to disturbance, and typically retains dateable traces of artifacts, organic material or calcite overlays.
As a result, many open air sites are eagerly awaiting new dating technologies (e.g. improved luminescence dating) which may provide direct evidence of their antiquity. The Côa Valley is no exception.
Up until recently, archaeologists relied entirely on stylistic comparisons with cave art to construct a timeline for Côa Valley sites.
They found three phases of activity connected to the era of Upper Paleolithic art.
The latest research, as documented by world-archaeology.com, focuses on a buried panel decorated with about 20 animal representations, which was recovered from sediments dating to the Early Gravettian period (28,000-21,000 BC).
Their art is hunter-gatherer art, which is presumably why the focus is on animals.
In total, more than 5,000 animal rock carvings have been found in the Côa Valley, including drawings of aurochs, bison, deer, horses and ibex.
At the archaeological site of Faia, in the south, there are a number of rare painted engravings, in which red ochre paint has been applied to outline the carving and highlight the mouth and nostrils of the animals.
The engraved drawings are found invariably on vertical rock faces, and sizes range between 15 cm (6 inches) and 180 cm (6 feet), averaging about 40-50 centimetres in height.
They often appear in clusters, forming multi-image compositions.
Côa valley engravings are similar in style to images preserved in caves and rock shelters in southwestern Europe. However, the Côa engravings are unique in that they depict movement.
This sense of motion is achieved by drawing a single animal body with two or even three heads, drawn to represent successive positions during movement.
Human figures are only present at Coa in rocks decorated between 16,000 and 12,000 BC. Even then, they are rare.
For example, they occur on only two rocks of the Ribeira de Piscos site, and on another two at the neighbouring site of Quinta do Fariseu.
For similarly aged rock carvings in caves, see Grotte des Deux-Ouvertures (26,500 BC).
Côa Valley engravers employed several different techniques:
In addition, in line with techniques used by artists at Chauvet Cave (34,500 BC) and elsewhere, variations in the morphology of the rock surface are used to give added relief to the animal figures.
As mentioned above, as far as paleolithic engraving is concerned, indoor examples (in caves and rock shelters) far outnumber outdoor examples - at least in Europe.
Only in Australia is the situation reversed - no doubt for climatic reasons.
The finest examples of open air Aboriginal rock art include:
Once again, direct dating is problematic, but most experts agree that the tradition of decorating rocks in all these areas dates back to at least 30,000 BC.
(1) "Into the daylight: a new rock art discovery." Thierry Aubry, António Fernando Barbosa, Luís Luís, André Santos, and Marcelo Silvestre. World Archaeology: Issue 101: May 22, 2020.
(2) "Prehistoric Rock Art Sites in the Côa Valley and Siega Verde". Lisbon, Portugal: IGESPAR – Instituto de Gestão do Património Arquitectónico e Arqueológico.