On this date, the Dutch surgeon, anthropologist, anatomist, and paleontologist Eugene Dubois was born. Dubois vowed to prove Darwin right by finding “the missing link”, the evolutionary connection between apes and modern humans. In October of 1891, while digging into fossil-rich ash and river sediments on the island of Java in what is now Indonesia, he found skeletal remains of what he later named Pithecanthropus erectus. The name meant “ape-human which stood upright.” Now known as Homo erectus or informally as “Java Man”, it is considered to be the direct ancestor of modern humans. Dubois was the first person to ever deliberately search for fossils of human ancestors. Only a handful of fossil humans had already been discovered, all Neandertals, and those were by chance.
Early African Homo erectus fossils (sometimes called Homo ergaster) are the oldest known early humans to have possessed modern human-like body proportions with relatively elongated legs and shorter arms compared to the size of the torso. These features are considered adaptations to a life lived on the ground, indicating the loss of earlier tree-climbing adaptations, with the ability to walk and possibly run long distances.
The most complete fossil individual of this species is known as the “Turkana Boy” — a well-preserved skeleton (though minus almost all the hand and foot bones), dated around 1.6 million years old. Microscopic study of the teeth indicates that he grew up at a growth rate similar to that of a great ape. There is fossil evidence that this species cared for old and weak individuals. The appearance of Homo erectus in the fossil record is often associated with the earliest handaxes, the first major innovation in stone tool technology.
Generally considered to have been the first species to have expanded beyond Africa, Homo erectus is considered a highly variable species, spread over two continents (it’s not certain whether it reached Europe), and possibly the longest lived early human species — about nine times as long as our own species, Homo sapiens, has been around.