However Homo erectus got to the island, once it arrived, Brown suggests its generations began to shrink in size. Fossils show that Homo erectus was fairly tall, standing, on average, 5 feet 10 inches. On Flores, due to the limited resources on the 31-square-mile island, smaller versions of the hominin may have survived best, since they would have required less food to survive. This could have led to the evolution of the new, miniature species.
Hot and humid weather on the island could also have favored smaller bodies in the same way it may have led to the small size of Pygmy populations who live in tropical forests of Africa. The theory is since the surface area of a small body is greater in relation to its volume, it's easier to cool off. Plus, less energy is needed to move a small person's body weight, so less heat is generated.
Similar factors were probably also at play to favor the pint-sized Stegodon, whose remains were found in the same cave as the tiny person. Evidence suggests the dwarfed people may have hunted the miniature elephant-like creatures in groups. The authors point to an array of stone tools, also found in the cave, which were likely used in the hunt and to butcher prey. Remains of a Komodo dragon, an oversized lizard that still roams the island today, were also found in the cave, along with charred bones of birds, rats and fish suggesting they may have been cooked and eaten by the small humans.
More puzzling than their body size, however, is the apparently puny size of the early humans' brains. Today, the average human brain measures between 1,400 and 1,500 cubic centimeters. Homo erectus had a skull that packed a brain about two-thirds the size of today's human brains, or about 800-1,000 cubic centimeters. The skull found on Flores suggests these small humans operated with a brain only 380 cubic centimeters in size -- the smallest known brain of any known hominin species.
Despite their brains' diminutive size, Homo floresiensis was apparently smart enough to make and use tools, use fire and to find the ideal shelter of the limestone cave.
"The fact that it had these behavioral associations with such a small cranial capacity is astounding," said Potts. "It's a little weird."
Despite the puzzlingly small brain size, Potts calls the discovery "terrific" and the research "convincing," although he adds that a team of paleo-anthropologists will need to see the bones and travel to the site in order for the science community to reach a consensus about adding a new branch to the already bushy tree of human evolution.
Other anthropologists are skeptical that the find is all it is cracked up to be. Yohannes Haile-Selassie, curator at the Cleveland Museum of Natural History in Ohio, thinks naming it a new species is premature.
"I have mixed feelings about this whole thing," he said. "This is one specimen. It could have a small body and brain size due to disease or pathology."
In fact, many anthropologists have argued that in recent years, scientists have been adding too many new species to the human evolutionary tree. They say scientists have become too quick to call what may simply be an unusual individual a member of a whole new species.
"This will definitely be fuel for the splitters over those who see many specimens as evidence of a new species," said David Begun, an anthropologist at the University of Toronto.