LOL, The Deaf cat (DC... I know, how original) does know some sign! He knows sit, no, his name, come, eat and water. All of them are American Sign except come. He is very willing, engaged and wants to please but is slow on picking up signs. But I am slow on learning new signs too... and far from fluent.
Oh, and that is his pic to the left. That is from Halloween last year... He loved the reaction when he jumped out at trick-or-treaters!