He's got green skin. He's got a long tongue. He's got a saddle on his back even when no one's around to ride on it and, well, he might not even be a "he" at all -- since he does have a habit of laying eggs. His name is Yoshi . And he's been with us now for 20 years.

Super Mario Galaxy 2's arrival in 2010 has marked the event, as, aside from being the next big sequel in Nintendo's main Mario series, the game's also served as an anniversary marker for one of its franchise's key secondary stars -- Yoshi the Dinosaur. It's an important and maybe overlooked point, especially since it's hiding in plain sight right on the box art. But Yoshi's a character who's been on the backburner for a while -- a mascot whose history with Nintendo has been a bit of a rollercoaster ride, as he's sometimes headlined games all by himself, sometimes been tossed into titles as a simple cameo or background character, and sometimes gone for years without seeing much action at all -- so it's an anniversary that might be easily missed.Coming into 2010, Yoshi was arguably coming off one of his long dry spells. The last game in the " Yoshi " series came out four years earlier, and his appearances in the interim were low-profile at best. Oddly, though, his appeal never seemed to have dropped off at all. His prominent role in Galaxy 2 was quickly accepted and praised, with marketing materials for the Super sequel happily placing him front and center. Wouldn't you think he'd have lost some star power over time? Wouldn't it make more sense that a character who's been used so inconsistently over his 20 year lifetime would command a bit less of a response from long-time fans, who'd had several other, more regularly appearing mascots to grow attached to?Well, we're here to explore that mystery. Like the fact that he's called a dinosaur, yet uses a tongue like a frog's. Like the fact that he's called a "he," yet lays eggs like a girl. We're diving into the many questions surrounding Mario's green steed, tracing his origins and development through all of his many game appearances through his first two decades, and ultimately trying to find the answer to why, exactly, such a wacky guy as Yoshi still has the power to charm us after all these years. Won't you join us? This is Yoshi: Evolution of a Dinosaur.Pre-History:On the Drawing BoardNow it's common knowledge that Yoshi's first ever appearance came in Super Mario World , the fourth main Mario series sequel that launched as the pack-in game for the Super Nintendo Entertainment System and almost single-handedly kickstarted the 16-bit era for Nintendo as a company. Slightly less well known is the fact that Yoshi had actually been around for several years preceding that game's release -- for over half a decade, in fact. An interview with Mario series creator Shigeru Miyamoto conducted twenty years ago revealed that the development team responsible for the mustached man's adventures had been wanting him to ride a dinosaur since just after the completion of the very first Super Mario Bros. game -- the game that came out in 1985.The technology just wasn't there, Miyamoto explained, back in that day -- the NES wasn't powerful enough to handle the concept (or, more likely, he and his fellow artists weren't yet experienced enough with the hardware to figure out how to make it happen). Super Mario Bros. 2 and Super Mario Bros. 3 came along in the years that followed, though, and both gave Mario much more vibrant and complex worlds to explore, along with a wealth of new power-ups and abilities -- and more programming expertise to his creators. Looking back, you can almost see the dream of their hero gaining that mighty stallion slowly becoming a reality, behind the scenes.Finally, in 1990, Yoshi made his official debut -- but only in Japan. We gamers here in America would have to wait one more year, as the localization process turned their Super Mario Bros. 4 into our Super Mario World, and their Super Famicom into our SNES. With that last bit of work completed, Yoshi hatched in the States in August of 1991 -- almost exactly ten years after Mario himself had first appeared, in August 1981's arcade release of Donkey Kong