It is usually assumed that only one species of early human lived in South-East Asia before modern people got there - Homo erectus. Furthermore, up to now, erectus fossils were only known in the region from China and the island of Java, in Indonesia.
East of Java, towards New Guinea and Australia, it was thought that deep water kept people from venturing further until the ancestors of Australian Aborigines used boats to hop across the intervening chain of islands, some 60,000 years ago. This simple picture was challenged when it was reported a few years ago that 800,000-year-old stone tools had been found on the island of Flores, some 300 miles (480 km) east of Java, but most experts wanted more evidence to back up the claim that ancient humans had migrated that far.
That evidence has now turned up in an extraordinary discovery from Flores. The skeleton of a three-foot-tall 'human' with a brain size no bigger than a chimpanzee has been excavated from the Liang Bua cave, together with stone tools and remains of a pygmy form of the extinct elephant called Stegodon. There are also bones of smaller animals, some of which have been burnt. What's more, the level in which the skeleton was found has been dated to only about 18,000 years ago, so modern people must have actually encountered this strange creature. What was it, what was it doing on Flores, and what happened to it?
The Flores find is so unexpected that deciding what kind of creature it represents is not easy. The possibility that it was a single abnormal individual can be discounted because other similar remains have already been found in the cave. Although the legs and hipbone suggest that it walked upright, like us, the hipbone resembles those of the prehuman australopithecines, who lived in Africa over two million years ago. Together with the very small brain size, this might suggest that this is actually some kind of australopithecine that migrated out of Africa millions of years ago. Yet details of the skull, the shape of the face, the small teeth, the evidence of tool making and, perhaps, hunting all suggest that the creature was fundamentally human. Thus the authors of the two papers about it just published in Nature have named a new human species Homo floresiensis after its island home. They suggest it could be a descendant of Homo erectus that arrived early on Flores, perhaps using boats, and under completely isolated conditions, evolved a very small size, as did the Flores Stegodon, on which it may have preyed.
The fate of Homo floresiensis is, of course, unknown. Climatic changes at the end of the Ice Age may have affected its habitat, or modern humans could have killed it off directly, or by consuming the resources on which it lived. However, there is the intriguing possibility that it lingered on, and is a source of legends of 'wild-men' living in the jungles of South-East Asia. Whatever the truth, its very existence shows how little we really know about human evolution in Asia.
Prof. Chris Stringer