Good question, @gman_arts! I think it depends on the style of cartoon that you’re going for. If it’s realism-based cartoons (think of Disney movie characters or comics superheroes), then, yes, it’s essential to be very familiar with realistic anatomy because those kind of stylizations rely deeply on it and require anatomical believabilty. For a more simple-shaped or stick-figure kind of cartoon (think of South Park or Peppa Pig), then I’d say it’s not necessary to delve into anatomy - although it might still help to know basic figure construction so you can maintain proportions and know where to place each part of the body, even if stylized. Hope this helps!