MAN: This just doesn't happen, man.
Well, it's happening.
In your lifetime.
NARRATOR: Now, a stunning find in an ancient lake
promises a glimpse into
this exotic Ice Age realm,
and at the fantastic creatures that ruled the land:
ancient elephants like mammoths and mastodons,
giant bison, sloths and camels.
KIRK JOHNSON: Tusks, skulls, pelvises, shoulder blades.
It was phenomenal.
There were so many bones.
NARRATOR: But there is a mystery about this find.
We really don't have a way to explain this.
NARRATOR: They're finding thousands of bones of many different types,
but most of them are mastodon, ancient elephants.