How come animals don't get sick when they eat other animals alive?
They have stronger bellies than we do. That's why their food would not (I repeat: NOT) be to good to eat! Blah! But they do sometimes get sick, so don't feed your pet mouse Whiskers to Spot anytime soon!
Cuz their digestion system is made for that
Sometimes they do. Animals can get parasites just like people do. But some parasites are specific to only one species of host. An animal of another species that eats the meat won't be infected.
Their stomachs are built differently than humans. That's why cat/dog foods are made differently, and we're not really supposed to feed them foods that humans eat