“bones have cut and gnaw marks on them” = observation
“must have been due to cannibalism “= conjecture
Which one is science and which one is fiction?
Which one is science and which one is fiction?
Well, if the knaw marks appear to have been made by human teeth (careful observation)...
Also, if the cut marks were made by a sharp blade applied in a striking motion, that might be inconclusive. Blade marks made by apparent "dining" would be more definitive. All this can be determined by expert forensic study (observation) which is really quite good, in 2019....
Now, trying to stretch apparent cannibalism into being due to warmer temps... That is conjecture, and weak conjecture at that.