Discovery Provides New Details on Early Use of Bone Tools

01A recent discovery of bones in Tanzania suggests early humans commonly used animal bones to make cutting tools 1.5 million years ago.

02Past research has shown our early ancestors made simple tools from stones as early as 3.3 million years ago.

03But bone tools appear to have been developed much later.

04The discovery in Tanzania included a collection of 27 formed and sharpened bones.

05It pushes back the date for ancient bone tool use by around 1 million years.

06Researchers recently described their discovery in a study in the scientific publication Nature.

07William Harcourt Smith is a scientist with the American Museum of Natural History.

08He did not take part in the latest research.

09Harcourt Smith told the Associated Press, The findings show that ancient humans used a number of materials and had rather more complex tool kits than previously we thought.

10The bone tools measured up to around 40 centimeters.

11Most of them came from the leg bones of large animals such as elephants and hippos.

12Early humans likely made the tools by breaking off the thick ends of leg bones and using a stone to remove smaller pieces.

13Inacio de la Torre is with the Spanish National Research Council.

14He helped lead the research.

15De la Torre said this method was likely used to create one sharpened edge and one pointed tip.

16The bone tools were probably used as a hand axe, he added.

17The hand axe was likely used for cutting up dead animals, de la Torre said.

18This kind of blade would be helpful for removing meat from dead elephant and hippo bodies.

19He explained, We don't believe they were hunting these animals.

20They were probably scavenging.

21Scavenging means to search for food from waste or dead animals.

22Some of the bone tools showed signs of having been hit more than ten times, suggesting careful work.

23Mirian Pacheco is a researcher with the Federal University of São Carlos in Brazil.

24She was not involved in the study.

25Pacheco said the newly uncovered evidence suggests early humans were thoughtful when choosing and making the bone tools.

26Researchers believe this because certain kinds of large and heavy leg bones were taken from specific animals.

27Also, the methods used to make the tools appeared to be regular or consistent.

28The researchers noted the bones showed only small signs of damage.

29Pacheco said she thinks this rules out the possibility that natural causes shaped the tools.

30The bone tools date from more than a million years before our species, Homo sapiens, arose around 300,000 years ago.

31At the time the tools were made, three different species of human ancestors lived in the same area of East Africa.

32That information comes from Brianna Pobiner of the Smithsonian's Human Origins Program.

33Pobiner was not involved in the study.

34The tools may have been made and used by Homo erectus, Homo habilis, or Paranthropus boisei, she said.

35It could have been any of these three, but it's almost impossible to know which one.

36I'm John Russell.