Guys, guys, guys, you just don't get it! Those are HOUSE cats. They eat canned cat food and people food! If you tell them they are supposed to catch those things, that they are prey, the poor kitties will look at you in HORROR!
"Eat THAT?????? Mooooommmy, that's just GROSS! Ewwwwwwww. Gag me with a spoon!"
Or even "Hey, I'm not going after anything that bites back! Not me, no siree bob! Did you know they have TEETH?"