They might look like a bunch of rocks, but scientists say this is the oldest-ever collection of hand axes, picks and other cutting tools used mainly by our ancient human cousins, Homo erectus.
A new analysis of the stone tools show they are 1.76 million years old - about 350,000 years older than previous estimates. That means the tools, which are classified as Acheulean, co-existed with more primitive tools known as Oldawan - scientists previously thought they didn't overlap. But ancient humans didn't drop the old technology like it was an iPhone 3 - they were seemingly slow adopters.
A group of French archaeologists originally uncovered the tools in the 1990s near Kenya's Lake Turkana where Turkana Boy, a 1.6 million year-old skeleton of an 8-year-old boy, was discovered in 1984.
More primitive Oldawan tools, which are 2.6 to 1.7 million years old, were also found in the Lake Turkana location. The new dating indicates that the Acheulean and Oldawan tools were in use simultaneously (probably by a different human species). But it's not clear whether Homo erectus brought the Acheulean tools to the Lake Turkana location from someplace else, or whether they were developed in that location side by side with the Oldawan implements. In either case, ancient humans didn't wait in line to get their hands on the new tech. The transition was surprisingly slow, according to Ian Tattersall, a a paleoanthropologist at the American Museum of Natural History.
"The Acheulean evidently didn't catch on widely for several hundred thousand years after it was invented, possibly for the same reasons - whatever they are - that it took a really long time to be adopted at all widely in Eurasia, even as African groups were evidently migrating out," Tattersall told The New York Times.
To determine the age of the implements, they used paleomagnetics, a technique that exploits the fact that rocks retain the magnetization imparted when they first formed. Check out this Nature supplement if you'd like to know more about how the scientists determined the age of the artifacts, or if you'd like to look at photos of some insanely old stone tools.