Discovering Our Distant Ancestors
The remains of a 30-year-old woman were found on the isolated Flores Island east of Java. She was very small – standing only about three feet tall, with a brain size of about one third the size of our own and half the size of H. erectus – about the size of a chimpanzee. Other remains were found in subsequent excavations, yielding evidence of about seven people, all similarly tiny.
It is thought that Homo floresiensis’ earlier ancestor, probably Homo erectus, may have migrated to the island and evolved into a smaller species as it adapted to the island's limited resources. This phenomenon, which scientists have come to call the “island dwarfism,” is common in the animal world but had never been seen in human evolution.
The remains were found together with stone tools of proportionately small size as well as evidence of the use of fire and of sophisticated, cooperative hunting techniques. Both the tools and bones date from 95,000 to only 13,000 years ago, long after H. sapiens had reached the island. Homo floresiensis evidently co-existed with modern humans on Flores for tens of thousands of years – the 30-year-old woman became known as “the hobbit.”
According to Rick Potts, director of the Smithsonian Institution’s Human Origins program, the small brain is surprising because it’s a major departure from the general evolutionary trend that the human brain grew over time. A full-size Homo erectus had a brain volume between 54.9 and 73.2 cubic inches, while modern human brains can reach 85.4 cubic inches.
“The answer is to not look at brain size,” paleoanthropologist Peter Brown, of Australia’s University of New England said when interviewed by The Washington Post. “We don’t have many more neurons than chimps do, but we use them differently. I think the crucial thing was probably the brain’s internal organization.”