Well......I refer to them as "The Brigade".....if that answers your question (Do we have squirrels around?)
I don't know though that they would spend that much time gnawing away on a big bone like that - I think Earle is right about it being raccoons. But I'm no expert or anything. Would be interesting to set up one of my trail cams....if I really cared enough to investigate further - which I don't.