h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

While only tangential to cartoon physics, cartoon physiology is directly related. I do not pretend to be an expert, but here are some of the things that come to mind.

Examples of the facts of Cartoon Physiology
The number of fingers on the cartoon hand is three, sometimes four. Cartoon characters usually wear gloves. [to be well dressed?????]

Cartoon animals frequently retain human physiology; standing on two legs, arms instead of front legs.

Cartoon females are very likely to have human breasts, regardless of whether they are human or animal. [This does not include cows, who have to have udders--or they wouldnt be cows] Corrollary: human females usually have very well developed 'upper bodies'.

There are probably many more of these, but that's what comes immediately to mind.