It does appear to have been well gnawed when fresh long ago.
Your recovery site might not be too far from bluff(s) Pottawatomie pottery was made on.
I don't know if they had many camp dogs that may have got any bones. Bones had multiple uses besides extracting the marrow though so a wild guess is a "wild" critter chewed on it.
I put a road hit deer in the woods for a fox family. The vixen had also been road hit.
They worked it well, but no large bones were reduced like your picture.
Rodents including porcupine make short work of hard calcium or salt containing stuff.
Your locations context matters though , and what type( if any) forest type back when the bone was fresh as to what critters were around.
You're close enough to a former major E-W trail down there that things could arrive from long distances...
Fresh meat would only keep so long though , except in colder seasons of the year. During which farther North towards me meant wintering in river valleys after leaving summer areas closer to the big lake.
Keep looking!
