I know that some artists see Sonic's design differently, but I'll be a bit of a bore!

When designing Sonic, the creators took into account the fact that real hedgehogs do not have fur on their bellies, lower faces, or paws. This is why the pink part of Sonic is skin, not fur. Consequently, the inner ears of other hedgehogs have the same skin color as their faces.

but then there were other hedgehogs that didn't have bare skin on their bellies and paws... and it just became a feature of Sonic's coloration. I'm curious to hear your opinion on this matter

Really? I've never heard of it before, but it kinda makes sense. Idk, I see the fur on their faces and bellies, I guess the design of the movie Sonic is close to me, it's clear that it's fur. It also seems to me that it's beige, not pink. Even real hedgehogs have some fur on these body parts.

yes, I meant beige. my English is bad

I'm sorry, but the pink fur on the Terios' chest made me think.