Israeli researchers say mysterious clay and stone artifacts from Neolithic times could be the earliest known "matches," used to start fires.
The cylindrical objects had previously been interpreted as "cultic" phallic symbols, but new evidence suggests they were "fire drills," to be rotated at high speeds to generate heat from friction and ignite tinder, researchers said.
"We have fire evidence in modern humans and Neanderthals, from charcoal, ashes and hearths, but there was nothing ever found that was connected with how you ignite the fire," Naama Goren-Inbar of The Hebrew University of Jerusalem told BBC News.
Goren-Inbar said the shape of structures discovered at the Sha'ar HaGolan archaeological matched that found in tools used for purposes other than simply cultural ones.
"I saw this object and immediately it came to my mind that this was very, very similar to all the sticks that you see [used as] 'fire drills,'" she said.
Microscopic examination showed telltale signs the cylindrical clay objects may have been rotated at high speed, she said.
Marks at the conical ends of the cylinders suggest the "matches" were spun within sockets found on "fire boards" which are known from other sites.
The research was published in the open access journal PLoS ONE.