Bone technology - such as its use as an arrow tip - was essential to a Stone Age man's lifestyle and has been shown to have been in use 60,000 years ago.
The majority of the evidence to support this has been found in sites in southern Africa, but now the artefacts found in the Kuumbi Cave show that this technology was being adopted in eastern Africa as well.
The researchers, including those from the Australian National University and Saint Louis University, studied seven bone artefacts recovered from the Kuumbi Cave, five bone projectile points, a bone awl, and a notched bone tube.
By analysing the artefacts with a camera and microscopes, they were able to compare the manufacture techniques and wear to previous discoveries and to attempts to replicate this technology in the laboratory.
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The findings showed that the bone projectile points are likely to have been used for poison arrows, partly due to the slender and short nature of the arrow heads, and partly supported by a previous discovery of charcoal from the Mkunazi plant, which is known to have poisonous fruit.
Previous work has estimated that poison-tipped arrows may have been used as far back as 24,000 years ago, and the researchers conclude that this technology, better known from southern Africa, may also have been used 13,000 years ago in eastern Africa.
The research was published in the journal Azania: Archaeological Research in Africa.