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And you can also see that, in the scene where Kaltag hits Star's chin, a human molar flies out of Star's mouth.

The point I'm trying to make is, the movie doesn't have to be 100% accurate. That's what gives it its charm.
And Boris would look weird without teeth, haha.

Yeah it is a cartoon, cant imagine him pulling that same face without teeth filling that wide grin of his but still a good thing to point out, I never really thought of the connection between teeth and geese not supposed to have em

I've seen birds with teeth in other cartoons, it is mot unique-though i cant think of any examples right now.

true, also it was probably done to add humour and make him seem more human.

Sheba

Haha I never thought about that xD But yeah it is probably to show expression and its the same with Zazu from TLK and other characters from various animated films

Like Iago from Aladdin. Though, really, Gilbert Gotfreid's voice demands a tooth expression.

Also, geese have teeth, but not nice choppers like Boris.

http://www.mdavid.com.au/geese/geese.html

^Haha wow! I never knew that geese had teeth XD I thought that they were like snakes and just had sharp gums or something haha

Geese can't usually talk, dance, or mop either, so I guess the movie has more than one thing wrong about Boris.

Man alive, I know that have teeth! One bit me when I was a kid, so I can tell you from experiance that they do indeed have their own set of chompers (Though not like Boris' humanized teeth). I suppose they did it so Boris would look more animated (Figure of speech)...