Horses cant wipe either but they do fine in terms if the smell. The trick is that they have an anus designed to prolapse a few inches so that the feces only ever comes into contact with the rectum and never exterior tissues.
If you haven't bought a bidet (like $50-100 and a few minutes to install) or shower every time you poop, you are probably covered in feces right now. Toilet paper alone is kind of gross.
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I did know before reading the post the reason we as humans are the only ones who wipe. Where did I learn this? From you (the internet) of course. Where else xD