This is some super secret squirrel stuff right here...
I think it is some type of theft deterrent system to keep Ernie safe from truck jackers.... Or this may be part of the new .00001 micron fuel filter system that utilizes the microscopic pours in mammal bone to filter out unwanted contaminates. Not only does it keep your fuel clean, but it also improves your (and your spectators!) health! The filter system enriches the fuel with small pieces of bone. When the fuel is burnt it atomizes the calcium from the bone into the exhaust for easy inhalation absorbsion. After two passes down the track, Ernie will have helped everyone reach at least 25% of the recomended daily calcium intake!