Related Clues:

• __ race
• "The Wind in the Willows" critter
• One down in the dumps?
• Certain stowaway
• Turn state's evidence, maybe
• One who squeals
• "Was it a ___?" "Yeah, a great big one" (line from "L.A. Confidential")
• Slum scurrier
• Mafioso informer
• Vole relative
• Pack __
• ___ Pack (Sinatra and pals)
• Inform (on)
• Urban vermin
• Chinese calendar animal ... or the key to this puzzle's theme