Humans are the strange, almost completely furless mammals that inhabit Station Square and various other areas. Since the beginning of the series, Dr. Eggman has been the only known human until other humans started to be seen starting with Sonic Adventure. They tend to be slow and lacking in attack abilities, and with the exception of characters like Chris Thorndyke and Professor Pickle, they are rarely seen doing anything of any real use (spending most of their time idly standing or walking around looking for someone to ramble to). Nevertheless, they are treated as if they were important.
In Sonic Unleashed, humans take on more cartoony appearances compared to previous games, and just about every human in the game has a unique design and name. Some humans will give Sonic missions to complete, while some would be possessed by Dark Gaia minions at night, making them behave very strangely and out-of-character, and thus require exorcism.
In Archie Comics' Sonic the Hedgehog, humans are depicted as the mildly interesting but fundamentally useless inhabitants of the hidden city of Station Square. Their strong resemblance to Overlanders has been questioned, but they can provide no explanation, and in fact were unaware of Overlanders until Sonic and his fellow Freedom Fighters mentioned them.