But Dr Kennett notes that present-day bison are not like the ones the Clovis people hunted.

ECONOMIST: Mass extinctions

Of course, that might just mean that the Clovis people had not quite exterminated bison before they, themselves, disappeared.

ECONOMIST: Mass extinctions

One is to look for evidence of population bottlenecks in other species, especially animals that were not hunted by the Clovis people.

ECONOMIST: Mass extinctions

So far it has been impossible to decide if these arrowheads were the tools of new people from Asia who replaced their dead cousins, or of a remnant of Clovis people who changed their technology and survived.

ECONOMIST: Mass extinctions