Scientists in South Africa have unearthed ancient stone points which were believed to be used to hunt by prehistoric humans some 64,000 years ago.
The University of Johannesburg researchers, who made the discovery from layers of ancient sediment in Sibudu Cave in South Africa, said the hunting tools are probably the earliest direct evidence of man-made arrows.
Closer inspection of the ancient weapons showed remnants of blood and bone that provided clues about how they were used, the scientists said, adding that the findings pushed back the idea that "bow and arrow technology" was developed 20,000 years ago.
Dr Marlize Lombard from the University of Johannesburg, who led the examination of the findings, described the approach she and her team took as "stone age forensics".
"We took the points directly from the site, in little (plastic) baggies, to the lab," she told BBC News.
"Then I started the tedious work of analysing them (under the microscope), looking at the distribution patterns of blood and bone residues."
Because of the shape of these "little geometric pieces", Dr Lombard was able to see exactly where they had been impacted and damaged.
This showed that they were very likely to have been the tips of projectiles — rather than sharp points on the end of hand-held spears.
The arrow heads also contained traces of glue, plant-based resin, thought to be used to fasten them on to a wooden shaft.
"The presence of glue implies that people were able to produce composite tools — tools where different elements produced from different materials are glued together to make a single artifacts," said Dr Lombard.
"This is an indicator of a cognitively demanding behaviour," she said, adding that the discovery pushes back the development of "bow and arrow technology" by at least 20,000 years.
Researchers are interested in early evidence of bows and arrows, as this type of weapons engineering shows the cognitive abilities of humans living at that time.
Detailing their findings in the journal Antiquity, the researchers wrote: "Hunting with a bow and arrow requires intricate multi-staged planning, material collection and tool preparation and implies a range of innovative social and communication skills."