While Pyjamas has playtime, I usually put a little cat food on the floor near him. While watching him eat the little pieces he appears to swallow them whole sometimes! He might open and close his mouth a couple times and then its gone! Don't they need to chew a little more? Same with the mini meal worms we gave him, he seemed to open and close his mouth a little then it was gone so fast. Maybe that explains his craziness after eating one, its still wriggling on the way down! Then sometimes I have noticed, usually after he has eaten something he will walk over to me, stand there on all four feet and sort of pulse his body for a little, then just be on his merry way again. Is that something to do with his digestion? He doesn't make any noise, maybe just a very soft sort of click with his mouth.