Video
 
Scrape Scrape Scrape
Yoda likes to "bury" his food when he's finished eating. Its an instinct left over from the wild, when he would wish to hide his presence from prey animals. He now also uses it to communicate when he'd rather eat something other than the food I've put down.

You'll see him at one point quite clearly sniff the food, look at me, then "bury" the food.   When he stops, I can often start him scraping again by doing it myself.

He has been known to go on for 20 minutes, he now has his very own scraping tray against the wall as the paint was coming off.