The Wharf Rats are a sub-group of Deadheads who are drug and alcohol free. Predominantly recovering alcoholics and or drug abusers. From the Jerry Garcia/Robert Hunter song "Wharf Rat" about a down and out wino hanging around the docks of San Francisco.
You can find the Wharf Rats congregating where the yellow balloons are during intermission.
by Woody Thomas January 07, 2006