This troper always thought they had one anus right in the middle of their body, it just wasn't visible (because, dude, it's a kids' cartoon). That's the theory that this troper sticks to because it's less squicky to her than the alternative (see above).
There was one episode which had the line, quote, "it has to pass through our colon," which verifies this theory.
This troper remembers an episode where they were snorkeling, and Dog makes a large fart bubble, which appears right in the center beneath them, verifying that this is where their anus is.
Possibly it would look like their bellybutton? It is in the right place to be either.
Well, at least in one episode they were shown peeing (although the camera zoomed away from the actual process, showing only their faces). It seems to be a mystery intended by the creators, since Dog spoofs it in another episode (I think it was an episode about a live-documentation about their species).
In the comics, Donald did have to repair his toilet bowl so...
We see Dog about to pee on a fire hydrant a few times, and he lifts his leg accordingly. So apparently they've got some sort of...exit on their body.
Lola figured that one out by barging into their bathroom. They have a LitterboxFireHydrant.
There's this one episode about...I don't know, something about eating habits, and a goldfish, and long story short, Cat disappears into Dog's mouth. I saw it when I was a kid, and I have literally not been able to figure it out for YEARS, because, get this, at some point, Cat comes OUT OF HIS OWN MOUTH, INSIDE OF DOG'S STOMACH. Just...how?!
Here's another one, how is it possible for Rancid Rabbit to have all these jobs and scam Cat so easily and he's the smart one. I was hoping someone would see Rancid as a restaurant and ask Catdog, "Hey Catdog, why is your doctor our waiter?" The only time Cat notices this is when Rancid appeared as a teacher and a Policeman. Also in "All you can't eat" why was Rancid crying when he got fired as Manager from Taco Depot when he has a hundred more jobs.
Cat actually lampshades this in one episode, where Rancid is a school principal for most of it and then appears again as a police officer at the very end.
How is it that nobody at all remembers that CatDog won in a lot of the episodes? In literally half of the episodes, they win or are otherwise unharmed, so how is it nobody remembers those episodes?!
In the episode about smuggling dogbones to serve in what amounts to a speakeasy, at the very end Winslow undersells CatDog by charging only $1 for what Cat had been charging $5 (and then $10 and planning $20) as well as hiring the Greasers as bouncers and bribing the cops so they look the other way. Realistically, how can he possibly expect to make a profit or get more money than Cat? Cat was getting more money for each individual bone and hadn't really bribed anyone or hired any employees (he's not shown paying them, at least). Even if Winslow paid the Greasers in bones, that's taking away some of his own product and thus losing money, and bribing the cops costs him more money. Cat had also been selling for longer, so even without his customers, he's gonna have more than Winslow for a while to come.
Cartoon writers don't necessarily know economics.
Do the Greasers really hate cats? Some episodes had Cliff interacting with feline characters in a non-negative manner, including taking dancing lessons with Randolph Grant (the cat with the replacement but), and trying to woo one of the twins sisters. None of the other Greasers see anything wrong with it. Is the reason they bully the titular duo (specifically Cat) less to do with species and more the fact that they're considered "freaks?"
Probably so. The Greasers' rulebook says "No two-headed freaks"...