How the bow and arrow helped humans to colonise the world

The invention of the world's first bows and arrows may have played a part in the eventual colonisation of much of the world by Homo sapiens.

In a groundbreaking paper published yesterday, Paul Mellars, one of Britain's leading archaeologists and a Cambridge professor, suggests Homo sapiens' dominance of much of the world was triggered by a technological revolution which caused a demographic explosion between 60,000 and 80,000 years ago. As a result, the population of one particular human ethnic group expanded up to 1,000 times over.

The dramatic population increase then forced tribes to search for new hunting grounds, first within Africa, and then, by 60,000 years ago, outside it.

The wide-ranging technological developments included improved cutting tools and new animal skin cleaning equipment, abstract art and more effective weaponry. The African tribes alsoinvented the world's first man-made projectiles - light-weight throwing spears and bows and arrows. The technological revolution was triggered by cooler and drier climatic conditions, and possibly human brain mutations linked to language development.

The research explains for the first time why our species started to expand across much of the planet a mere 60,000 years ago - despite having existed in Africa for the previous 100,000 to 140,000 years (Homo sapiens first developed in southern or eastern Africa sometime between 200,000 and 150,000 years ago).

"The new analysis - based on field workover the past 10 years - reveals how the period 60,000-80,000 years ago was of immense importance in pre-history. For it is becoming clear that a series of crucial human inventions at that time was the factor whichled to anatomically modern humanity's conquest of the planet," said Professor Mellars.

The technological revolution and consequent population explosion allowed Homo sapiens to spread along the coastlines of Arabia, India, south-east Asia and Australia between 50,000 and 60,000 years ago.