Petroglyphs can't be attributed to a specific person, but sometimes to a specific group of people.

Scarring with a hard tool can produce visible lines in the rock or the patina on the rock surface can be scrapt off so that the different color of the rock underneath is to see.

Rock art, news from the older days

A petroglyph is a rock carving made by pecking directly on the rock surface using a stone chisel and a hammer stone. 

It can made directly on the stone or only the patina on the surface, the lighter rock underneath was exposed.

Petroglyphs can be found around the world, except in Alaska. 

Longer before writing was developed, people recorded events, ideas, plans and there feelings by marking them on rock.

Sometimes they carved into stone, sometimes they painted (Pictographs). The method that they used was determined by hardness of the rock or tools they could use.

All are known as Rock art and can still be found, although they are 1000's of years old. The oldest are usually found in rock shelters and caves.

The representations are usually difficult or impossible to unravel because they have a high cultural and religious testimony. Unfortunately this knowledge is lost during the time.