Sonic the Hedgehog is a video game series. It is published by Sega, with entries developed by Sega, Sonic Team, Dimps, SIMS Co., Ltd., BioWare, and Sumo Digital. The series debuted in 1991 with the video game, Sonic the Hedgehog, released for the Mega Drive video game console (named Sega Genesis in North America). In its earliest history, most Sonic the Hedgehog games had been platform games released for Sega video game consoles and handheld game consoles (handhelds), dating from the Sega Genesis to the Sega Dreamcast. However, some of the original games were ported into versions on newer third-party home consoles and developed by various companies. As of March 2011, the series has collectively sold 89 million copies worldwide across both the platform games and spin-offs.