Related Clues:

• Cause persistent worry
• Work one's incisors
• Act like a rat
• Chew, as a beaver
• Chew on a bone
• Bother (with ''at'')
• Exhibit beaver behavior
• Mice and beavers do it
• Chew on rawhide
• Mimic a mouse
• Work on a bone, dog-style
• Enjoy a bone
• Agitate (with ''at'')
• Act the rat
• Nibble persistently