THE earliest inhabitants of North America differed subtly but significantly from modern native Americans. But anthropologists cannot agree why.
The difference is clearly seen in the skull shapes of the first people to colonise the continent, who had longer, narrower skulls than modern people. One theory says it is because two distinct groups of people migrated to North America at different times. But another says that just one population reached the continent and then evolved different physical attributes except for a few isolated groups.
Anthropologists once assumed the earliest Americans resembled modern native Americans. That changed with the discovery of…
