Cambridge archaeologist Mark Sapwell is using software to analyse thousands of Bronze Age images imprinted by generations of semi nomadic people on two granite outcrops the size of football pitches. "These sites are on river networks," explains Sapwell. "The rock art I'm studying is found near rapids and waterfalls… natural spots to stop and leave your mark as you journey through."
     The two sites that Sapwell is investigating, Zalavruga in western Russia and Namforsen in northern Sweden, each contain around 2,500 images of animals, people, boats, and hunting scenes. "Although this rock art has been documented from the early 1900s, the modeling has allowed a unique look at the interesting way these images have been arranged and accumulated over time," says Sapwell.
     Some of the first rock art - around 6,000 years old in Sweden - mainly depicts animals such as elk. Another find in the early periods is hybrid imagery (for example a half-man half elk, or half-man half-boat) which becomes less popular from around 3500 BCE.
     "One exciting part of the study is that the preference towards these popular images change through time." At Namforsen there is a shift is to boat images around 2000-1800 BCE, when long-distance trade was becoming more important. "So generally, what we see in these landscapes are very interesting cases where through prehistory, particular themes in everyday life become worth commenting on. A little like the fashions of Facebook comments, these topics are seen to fall in and out of favor," Sapwell said.
     According to Sapwell, the enormous natural canvases attracted so much interest because their social network power was well understood by early Bronze Age people. "Like today, people have always wanted to feel connected to each other - this was an expression of identity for these very early societies, before written language," Sapwell said.

Edited from Cambridge News, Discovery News (18 May 2012), PhysOrg (21 May 2012)