Maybe it was just hungry?

Bob Levy sent in a photo and wrote:

I watched this Gray Squirrel dig out an acorn and proceed to gnaw away at it. There was nothing particularly unusual about that. Only after I downloaded the image did I notice the mud all over its meal. The animal made no observable effort to clean the acorn and I imagine that a considerable portion of it must have been ingested. Judging by how enthusiastically the animal devoured the muddy acorn I wondered whether mud might be a Gray Squirrel condiment for a reason. Could there be a nutritional or digestive benefit? Maybe, but I for one won’t be doing any personal taste testing. But seriously folks, does anyone know if ingesting soil somehow benefits the squirrel?

Ps. Wood Duck fans: The male is still hanging out with the Mallards along the Riviera north and east of Bow Bridge