Cats, they always keep themselves clean.
Pigs are not the cleanest, clearly the truth is out there, Pigs live in their own faeces and I would advise you visit a farm. Pigs have been banned for humanity, firstly the Jews, then Christians and then Muslims. All 3 faiths have same God however SOME faith took on priest made laws and made legal what they pleased.
It is scientifically proven also, but do not believe in Media, look up research journals.
Bring in facts and proof.
Although it doesn't look like it, a pig! is the cleanest animal on earth! Go "pig"ure!