Scientists in Italy have discovered 350,000-year-old tracks that may be the oldest known footprints by Stone Age man.
The prints were made by three upright-walking humans as they descended the treacherous side of a volcano -- perhaps to escape an eruption, researchers reported in the March 13 issue of the journal Nature.
Other scientists said that although the prints appear well-preserved, they add little to knowledge about human evolution since footprints of older human ancestors have been found. But they said the tracks are still a sobering testament to long-ago journeys across harsh terrain.
One of the footprint trails zigzags to find the safest path down the steep incline. Another includes handprints someone left as he steadied himself in a precarious spot, only to slide a short ways down the slope.
"You're looking at an event that happened 350,000 years ago -- someone made an imprint on a surface, walking in a way you'd expect to see someone in these same conditions walk today," said Owen Lovejoy, an anthropologist at Kent State University who was not involved in the research. "It adds another cog in the connect between ourselves and our ancestors."
Who left the 56 footprints is not clear. But their discoverers suggest either late Homo erectus or Homo heidelbergensis -- early human species found in Europe during the Paleolithic era, also known as the Stone Age. The tracks were dated between 325,000 and 385,000 years old.
Footprints left by the upright-walking, prehuman species Australopithecus afarensis were found in 1977 in Tanzania, imprinted in volcanic mud 3.6 million years old -- making them 10 times older.
"The bottom line is that these are interesting curiosities that do not advance our knowledge of what happened when in human evolution," said Tim White, a University of California paleontologist who co-discovered the most famous Australopithecus fossil, dubbed Lucy, in Ethiopia in 1974.
The more recent tracks were found in southern Italy's rugged Roccamonfina volcano complex, north of present-day Naples.
Their makers were short -- just under 5 feet tall -- based on the prints' length of less than 8 inches, the researchers said.
The trails were left by three individuals who walked across a cooled but recent volcanic flow of rock fragments, ash and gases. A short time later, the volcano erupted again, blanketing the footprints with a thick layer of ash that preserved them for the ages, said Paolo Mietto of the University of Padua, Italy.
The tracks show that their owners were descending, not climbing, he said.
"The idea that these humans were escaping an eruption ... is attractive and is supported by the fact that all tracks have the same direction, outwards from the volcano's main crater," Mietto said.
Local residents had long known of the footprints, referring to them and to animal tracks preserved near the volcano as "devils' trails."
Mietto said the prints are unmistakably human. Some even preserve the foot's plantar arch and individual toe prints.