In paleontology it can only be estimated how long a species lived or a phenomenon existed. The beginning of a species’ tenure on this earth is marked by the oldest specimen that we have of it, and the end by the youngest specimen. But given that the fossil record is spotty, chances are that the oldest specimen is not from the very beginning, and the youngest right from the very end. So the temporal range of an extinct species is certainly at least a bit longer than our current fossil specimens would indicate.

This situation also means that on a regular basis the time range of species and events will be modified by new finds. We are constantly expanding and modifying our reconstruction of the past in this manner.

But still it is always exciting to learn that something interesting is much more ancient than we previously believed – such as human toolmaking. A recent find provides smoking-gun evidence that our ancestors were making stone tools about 1 million years earlier than indicated by previous evidence.

The oldest known stone tools date to about 2.5 million years old. These were found in the Afar region of Ethiopia between 1992-1994 – so that has been the oldest evidence of human stone tool use for the last 16 years. The evidence is comprised not just of the stone tools themselves, but the cores and flakes that result from toolmaking. There were no hominin remains found with the stones, however, so we can only speculate which species made them, but it must be an Australopithecus species since no Homo species yet existed (as far as we know).

The new find is not of older stone tools, but rather evidence of their use. Bones found in the Dikika region of Ethiopa date to between 3.2 and 3.4 million years old. They have marks on them that were made before they fossilized and are clear evidence of stone tools cutting the meat off the bone. The scrapes and mark show the signs of being made by stone when examined under a microscope, and some even have bits of stone embedded in them.

The likely species to be responsible is Australopithecus afarensis, the most famous example of which is the Lucy skeleton.

Using stone tools to cut meat from bones does not mean they were hunters. This evidence is still compatible with scavenging. Evidence from later finds is highly suggestive of scavenging – specifically stone cut marks laid on top of tooth marks from predators – meaning that our ancestors were eating the kills of other animals.

Also, the bone evidence does not tell us much about the stones used to do the cutting. Clearly they needed some kind of edge, but we do not know if the stones were worked the way later stone tools were. Perhaps no stone tools were found from this time because they are not there to find (always tricky to draw inferences from the lack of evidence, but that’s what we have to go on so far).

It makes sense that our hominid ancestors would have used wooden or organic tools at some point. Today chimps have been seen modifying and using sticks to fish termites out of their mounds. But such tools would not fossilize. Also, our ancestors likely used unmodified stones as weapons and tools for a time – but they would be just stones, and no way for us to know how they were used by our ancestors. So in terms of the tools themselves, our knowledge of the oldest tool use of hominids would be from the first stone tools sufficiently modified or crafted for us to recognize them as tools. (And as I said, this now stands at about 2.5 million years old).

But also, as this new evidence shows, we also have indirect evidence of hominid stone tool use by the marks they left behind on bones that later fossilized. Perhaps this bone evidence will always predate evidence of tools themselves, because of the probable period in which early hominids used unmodified stone tools.

Of course it would be nice to find one site in which we have bones with stone marks, fossil remains of the hominids who made those marks, and the stone tools they used – all together. Such a site may be out there waiting for some lucky paleontologist to find it.