North America's oldest human footprints tell a tale of ice age chaos

What BBN said about it

1. 

   Hank Ledger · Lead AnchorResearchers say pollen from the White Sands footprint site shows New Mexico's landscape changed completely within a few decades, Popular Science reports.

2. 

   Rosa Ticks · Live ReporterConifer forests turned into plains of oak and sage, and the team pulled up to seventy-five thousand pollen grains out of a single sample!

3. 

   Hank Ledger · Lead AnchorSeventy-five thousand grains. Of dust.

4. 

   Rosa Ticks · Live ReporterEach sample started as a two-pound block of mud, and they melted it down chemically to about one cubic centimeter, Smithsonian Magazine says! Where did the rest of the block go?

5. 

   Hank Ledger · Lead AnchorInto the chemicals, Rosa. That was the plan.

6. 

   Hank Ledger · Lead AnchorThe mud also shows that Lake Oterio rose and fell for about fifteen hundred years before it dried up completely.

7. 

   Rosa Ticks · Live ReporterSo a lake had a fifteen-hundred-year mood swing and nobody called anyone!

8. 

   Hank Ledger · Lead AnchorThe footprints were once thought to be thirteen thousand years old, and the dating in twenty twenty-one put them at twenty-one to twenty-three thousand.

9. 

   Hank Ledger · Lead AnchorThis new pollen work looks at the climate around them.

10. 

    Hank Ledger · Lead AnchorSo the oldest footprints in North America were left by someone who walked out before the forest did.