Human ancestors were tooled up

Recently-discovered bones in Ethiopia suggest that human beings (at least as we know ourselves) did not invent the first tools.

The bones were found by Zeresenay Alemseged, a palaeoanthropologist from the California Academy of Science. He led a previous expedition in the same region that uncovered the remains of Selam, otherwise known as Lucy’s baby, one of the most complete fossils of a human ancestor.

The new bones are from two unknown animals. It’s not the animals themselves that are attracting attention, but rather cut marks which indicate the bodies were cut with tools rather than teeth. Chemical tests confirmed the marks were made before the bones fossilized, meaning they weren’t added later on, for example through trampling.

Nature reports that the bones have been dated as between 3.24 and 3.42 million years old through radioisotope study of the surrounding earth. That’s significant as the earliest previously known tools were 2.5 million years old, coming from around same time the first humans appeared.

Given the location and age of the bones, the tools will likely have been used by the Australopithecus (depicted right). That’s the genus from which one species is thought to have evolved into the homo genus from which human beings derive. To date they’d largely been assumed to be vegetarians.

It appears our ancestors didn’t use the tools for hunting, but rather for removing meat from animals that had been killed by other predators. That’s also an important discovery as species closely related to humans, such as chimpanzees, don’t realize that a carcass of a large animal can be a source of food.

The next mystery to be solved is whether the australopiths intentionally created the tools by modifying rock, or if they simply used naturally sharp rocks. Either way, there certainly appears to have been some planning involved as the nearest source of rocks was around four miles from where the bones were discovered.


2 Responses to Human ancestors were tooled up

  1. Last weeks' Science Friday had him on the show, along with a skeptical opponent of this idea. It was quite heated.