DarkFireTheHedgeHo
The Uncontrollable Flame
Knuckles goes super in Sonic 3 and Knuckles,
Tails goes super with the Super Emeralds in Sonic 3 and knuckles,
Blaze goes super (although she's called "Burning Blaze") in Sonic Rush and Sonic Rush: Adventure.
So yes, the majority of Sonic characters that can go super are Hedgehogs, but other characters can go super as well.
lol I guess SEGA thought if one could go super why not ALL of them?
....They used the DBZ effect...where everyone could have a super in some form.....except girls.