1 TEL AVIV, Israel - If you thought recycling was just a modern phenomenon championed by environmentalists - think again.
2 Our prehistoric ancestors learned to recycle the objects they used in their daily lives thousands of years ago.
3 Researchers presented the evidence at a conference in Tel Aviv.
4 It's the first time researchers have shown how much cavemen recycled and how they did it, said Ran Barkai.
5 He's an archaeologist and one of the organizers of the four-day meeting at Tel Aviv University.
6 Early humans collected discarded and broken tools made of flint and bone to make new utensils, Barkai said.
7 It's just like we recycle paper and plastic today, he explained.
8 The recycling appeared at different times and different places, he told The Associated Press.
9 The methods depended on the materials and the surroundings.
10 Archaeologists have been finding recycled tools from caves in Spain and North Africa to sites in Italy and Israel.
11 Experts from 10 countries met for the conference to figure out what that means for our ancestors.
12 Recycling was common among early humans and also their ancestors, Barkai said.
13 The early recycling shows it was a survival strategy, said Avi Gopher, a Tel Aviv University archaeologist.
14 Maybe early humans they didn't worry about pollution and the environment, but they shared some of our motivations, he said.
15 'Why do we recycle plastic? To conserve energy and raw materials,' Gopher said.
16 Recycling flint and bone means you don't have to go get more, so you save energy and materials, he said.
17 Some cases could go as far back as 1.3 million years ago, said Deborah Barsky, an archaeologist with the University of Tarragona.
18 A find near a prehistoric lake in Spain found basic reworking of flint, she said.
19 But she added it was hard to tell whether this was really recycling.
20 'I think it was just something you picked up unconsciously and used to make something else,' Barsky said.
21 'Only after years and years does this become systematic'.
22 That started happening about half a million years ago or later, scholars said.
23 A dry pond near Rome has yielded bone tools, said Giovanni Boschian, a geologist from the University of Pisa.
24 They were used some 300,000 years ago by Neanderthals who hunted there, he said.
25 'We find several levels of reuse and recycling,' he said.
26 'The bones were shattered to extract the marrow, then the fragments were shaped into tools, abandoned, and finally reworked to be used again'.
27 At other sites, stone hand-axes and discarded flint flakes were used to make smaller tools like blades and scrapers.
28 Sometimes hominids found a use even for the tiny flakes that flew off the stone.
29 Gopher and Barkai found flint chips between 200,000 and 420,000 years old in a cave near near Tel Aviv.
30 They had been reshaped into small blades to cut meat - a primitive form of cutlery.
31 Some 10 percent of the tools found at the site were recycled in some way, Gopher said.
32 'It was not an occasional behavior; it was part of the way they did things, part of their way of life,' he said.
33 He said scientists have ways to determine if a tool was recycled.
34 They can find direct evidence of retouching and reuse, or they can look at the object's patina - changes in color once stone is exposed to the elements.
35 Differences mean a fresh layer was exposed hundreds or thousands of years after the tool was made.
36 Some participants warned about comparing it with today's recycling that's driven by environmental worries.
37 Prehistoric recycling was done out of need, said Daniel Amick, a professor at Chicago's Loyola University.
38 Participants in the conference plan to submit papers to be published next year.
39 They will appear in a special volume of Quaternary International, journal that studies the last 2.6 million years of Earth's history.
40 Prehistoric recycling had come up in past studies, said Norm Catto, the journal's editor in chief.
41 But this was the first time experts met to discuss the issue in such depth.
42 Prehistoric recycling could give clues about how early humans traded and moved around, he said in an email.
43 Above all, he said it reflects how humans have similar responses to the challenges of life over thousands of years.

Our prehistoric ancestors learned to recycle the objects they used in their daily lives thousands of years ago .
objects
What objects?