Per an internet search, the same reason squirrels bury food…it’s a type of food caching.

Burying a bone enhances the flavor and aroma of the bone making it succulent and delicious.

You and I not being dogs it is difficult to explain but I think it is for similar reasons that food is returned to the fridge rather than left lying around.

They’re hiding it from other animals. They can go back later & dig it up to chew on it some more. This is a habit that began before they became domesticated & received regular feedings. Back then, the bones actually had meat on them that coud feed them later!!!

They bury stuff, like dog biscuits, to save them for later.
I have never seen a dog bury a bone.

My guess is to mask the odor of the bone so other animals don’t find the bone or find the dog for that matter.

Our dogs bury hard, dried rawhide too. They later dig them up and the rawhide is soft and chewy. Yum!

^^ My male Black Lab did that & it ALWAYS made me gag. He’d chew until it was good & slobbery, bury it, & then wait until a heavy raining day to dig it up & go back to munching. I found it disgusting…he seemed to enjoy the dirt/mud!!!

Earthy flavor notes!