Lance again.

Here's an interesting article: Petite skull reopens human ancestry debate. A new wrinkle in the search for our anthropological past.

The remnants of a remarkably petite skull belonging to one of the first human ancestors to walk on two legs have revealed the great physical diversity among these prehistoric populations.

But whether the species Homo erectus, meaning "upright man", should be reclassified into several distinct species remains controversial.

The theory I find most interesting is that two or more higher species of primates developed at the same time, but one, homo sapiens, either became dominant, which led to the extinction of the others, or was the result of interbreeding among them.

The questions that theory leaves behind are: why did they all develop in the same general area, and why did other primate species not develop the same cognitive abilities?