Homo floresiensis is the species name given to a small group of fossilized hominid remains discovered in 2003 on Flores, an island in Indonesia. The skeletons look ostensibly like the human ancestor Homo erectus; however, they had both tiny bodies and tiny brains. Dating performed on the discovery sites indicates that these individuals lived as recently as 12,000 BP (before present). There has, however, been a great deal of controversy over whether or not these individuals actually represent a previously undiscovered species of hominid or if they merely represent a population of skeletally pathological individuals.
If H. floresiensis does represent a non-H. sapiens species, it is a tremendously important find for two major reasons. These are the recency of the species’ time on Earth and the implications the finds have on the nature and organization of the human brain.
If H. floresiensis is a separate species, it is by far the longest-surviving non-human hominid. Extant as recently as 12,000 BP, these hominids are twice as young as the most recent H. neaderthalensis, which has long been thought to be our most recent companion on the planet. This discovery could rewrite the history of recent hominid evolution, with different hominid species living and competing with each other almost until the advent of plant and animal domestication. This would be a profoundly interesting revelation.
H. floresiensis, standing less than three feet tall, had a cranial capacity of approximately 380 cc. This is far smaller than modern humans (on the order of 1350 cc) of H. erectus (approximately 1000 cc). It is even considerably smaller than chimp brains, which hold around 450 cc. More important for measuring intelligence than raw size, however, is the ratio of cranial capacity to body size. That said, even when correcting for the small body size, H. floresiensis’ brain is smaller than a chimpanzee’s. Paradoxically, H. floresiensis sites are littered with evidence of advanced thought and behavior, including the manufacture and usage of sophisticated stone cutting tools and the manipulation of fire. This revelation is deeply important to shedding light on the evolution of the hominid brain. Several areas of the prefrontal cortex which are highly associated with modern intelligence are just as big in H. floresiensis as in H. sapiens.
This is important because it tells us something fundamental about the Australopithecine brain. Members of the genus Australopithecus, some of our earliest ancestors, had brains sized similarly to apes but which were organized somewhat differently. It has long been unknown whether and how much brain organization could supersede brain size as a driving force for intelligence. H. floresiensis appears to support the hypothesis that a well-organized brain is as good as a large brain for producing human-like intelligence. The power of brain organization may also be a factor in the behavioral differences between H. sapiens and H. neanderthalensis. Counter intuitively, Neanderthals had bigger brains than modern humans. Evidence about the importance of hominid brain organization could very well help anthropologists to better understand the differences between each member of our hominid family.