Scientists have recently found 3 million years old stone tools in Kenya, in a discovery that will improve upon a lot of existing theories. These are the oldest such artifacts that have been discovered at the time and this age is very long before the arrival of modern humans. The stone tools found in Kenya push the date of such artifacts by 700,000 years. It’s possible that the makers of these stone tools may or may not have been ancestors of modern humans. The recent discovery has been described in a paper published in the journal Nature.
The astounding discovery is the very first evidence which proves that an earlier group of humans may have possessed thinking abilities that allowed them to create sharp tools. The authors of the paper say that the tools are a new beginning in the existing archaeological record.
A co-author of the study, Chris Lepre, a geologist of the Lamont-Doherty Earth Observatory and the Rutgers University said that the site is surprising and that it rewrites the book on many things that people thought to be true.
The recent find was almost an accident: Lewis and Harmand claimed that they wondered off on a wrong path in 2011 on July 9 and that they climbed a hill in order to find a route leading back to their initial track. They wrote that they felt something special about the place and they scattered to examine a patch of outcrops nearby. They also said that by teatime, Sammy Lokorodi, a Turkana tribesman helped them discover what they were looking for.
By the end of the field season in 2012, the excavations on the site, called Lomekwi, had revealed 149 artifacts made of stone that were linked to tool making. Those artifacts range from rocks used as hammering tools to flakes and stone cores and other tools used probably as anvils.
Lead author Sonia Harmand from the Turkana Basin Institute said that the tools shed a new light on a previously unknown and very unexpected period of the hominin behavior and that those tools can tell a lot about the cognitive development of our ancestors that it’s impossible to understand just from studying fossils alone.
Hominins are a class of species that includes Homo sapiens, our closest ancestors and modern humans. Anthropologists have thought for a very long time that our ancestors inside the Homo genus were the first ones able to craft such tools. The Homo genus is the line that leads directly to Homo sapiens. However, researchers have been revealing incredible clues that indicate that some earlier species of hominin might have been able to craft those sharp tools.
The scientists don’t know at the time who crafted those extremely old tools but earlier discoveries do suggest a possible answer: the skull of a 3.3 million years old hominin was found around a kilometer away from the site where the tools were found in 1999. The discovered hominin is called Kenyanthropus platyops. Another bone from the skull of said hominin and a tooth were also found a couple of hundred meters away from the dig site and another unidentified tooth has been discovered around 100 meters away.
The exact family tree of the modern humans is controversial and at the time no one really knows how Kenyanthropus platyops is related to other hominins. Kenyanthropus platyops predates the earliest Homo species by 500,000 years. That species could have crafted the tools, or, it is possible that the unknown toolmaker could have been another species living around the same era, like an undiscovered early kind of Homo or Australopithecus afarensis.
Lepre said that a coating of volcanic ash below the site matches some other ash that was found elsewhere and that has been dated to around 3.3 million years in the past. This deduction was made by analyzing the ratio of argon isotopes inside the material. Co-author Dennis Kent and Lepre examined the magnetic minerals beneath the site, above and around the place where all the tools were found in order to define the time period more accurately.
Another co-author of the study and Lepre’s wife, Rhoda Quinn studied the carbon isotopes inside the ground, which together with the fossils from animals found at the site allowed the scientists to remodel the vegetation in the area. By doing this, the scientists uncovered yet another surprise: the area was a shrubby, partially wooded environment at the time. The scientists deduced that the tool making came as a response to a climate change that brought the spread of vast savannah grasslands throughout the area and the evolution of certain animals that could have served as a food source for the ancestors of humans.
Another co-author of the study, Jason Lewis from the Turkana Basin Institute and Rutgers thinks that hominins may have started banging a rock against another in order to make sharp edges so they could use the tools to cut meat off of animals. However, the markings found on the rocks and the size of the recently discovered tools imply they were doing something else, especially since the hominins were in a wooded environment and had access to numerous plants. The scientists believe that the tools may have been used for opening tubers and nuts, bashing logs in order to get access to the insects found inside, or maybe something entirely different that no one has yet thought about.
Some earlier dating work done by Kent and Lepre helped lead to another study in 2011: a paper claiming that Homo erectus was using advanced tool making techniques 1.8 million years in the past. This is at least 300,000 years earlier than was previously thought.
Lepre said that even though he realizes that when those things are figured out, nothing is actually solved and new questions are just being opened up, he still gets really excited thinking that there is a lot more work to be done.