bazzer:
That's not strictly true. My cat took one out once. Sadly, he's a bit older now and I'm not sure he's up to it, otherwise he would definitely have volunteered!
Back when we owned a Dorgi (Dachshund/Corgi cross) I found a headless possum on the back lawn one morning. No sign of the head. Not sure if she had eaten it (difficult I would have thought), or had buried it somewhere not obvious 😱