Old pigs have hard snouts.
More German Proverbs:
Be not ashamed of your craft.German
Said in sport, meant in earnest.
German
One does evil enough when one does nothing good.
German
The fox changes his skin, but keeps the rogue.
German
He who is born to misfortunate stumbles as he goes, and though he fall on his back will fracture his nose.
German
The cat's play is the mouse's death.
German