A Fox and an Island Provide New Clues.

• Position: EVOLUTION

Nearly two decades ago, a small-bodied "human-like" fossil, Homo floresiensis, was discovered on an island in Indonesia. Some scientists have credited the find, now nicknamed "Hobbit," as representative of a human ancestor who developed dwarfed features after living on the island, while others suggest it represents a modern human suffering from some type of disease because of its distinct human-like face and small brain.

Colleen B. Young, a graduate student in the Department of Anthropology at the University of Missouri, believes the Hobbit adjusted from a longer-legged version of itself to meet the demands of an isolated, island environment.

Homo erectus, considered our recent ancestor, likely devebped its long legs over time in order to increase its ability to walk long distances as its environment expanded. So, when humans arrived on that island in Indonesia and became isolated, their bodies--once built for efficiency over long distances--were probably no longer beneficial for their new environment. Instead, a smaller body size probably improved their lifestyle.

Young, who is working on her doctorate in biological anthropology, tested several popular assumptions about the characteristics of Homo floresiensis by comparing an island fox from California's Channel Islands with its mainland U.S. relative, the gray fox. Upon arrival, the island fox underwent a 30% reduction in body size and developed smaller body features that are different from the mainland gray fox. She believes this change in body size was likely due to adjustments the island fox made...