Scientific American interviews Peter Brown, who led the startling discovery of Boing Boing's new mascot, the meter-tall human species Homo floresiensis that lived on the Indonesian island of Flores as recently as 13,000 years ago.
"Looking at the distribution of small-bodied animals around the world today, they tend to occur in rainforests… And certainly that's where small-bodied humans tend to be found. We don't know much about the paleoenvironment on Flores yet, but everything's consistent with it being heavily rainforested back in the Pleistocene and probably heavily rainforested until agricultural humans arrived and started clearing the rainforest. The fauna is consistent with that sort of environment as well. Maybe there just wasn't a lot to eat. The island is only about 14,000 square kilometers, there's not a lot of it there. So I think the most likely scenario is that as part of their adaptation to [having fewer] calories living in a rainforest–and maybe thermoregulation as well–there was this long-term selection for smaller body size."