Maybe they just followed the animals...easy to do when you live with them
Especially if they are hunters.
Nice rationalization.
But that was NOT their EXPERIENCE.
They reported that they
SAW
AND
HEARD
it evidently days ahead of time.
There are at least a couple of plausible spiritual answers to this--that they were communicated with from outside of time.
There are some other possible explanations.
But I prefer to take people at their word. I at least respect their own report of their own experience.