This is mostly taken from my first ever #TBT way back in August of 2014. Enjoy.
It all begins in 1857. This is your classic tale: corrupt politicians getting compared to rodents, and everyone's ignorance about which rodents look like Gophers and which don't. Check out the entire story in the 2003 Minnesota Daily article.
I'm a company man (shoutout to the Minnesota Historical Society letting me do this for a living), so I should mention that the original R.O. Sweeney satirical cartoon is currently on display at the Minnesota History Center in downtown Saint Paul.
So the University of Minnesota coped the name the Gophers. Exactly when is a bit unclear, the first yearbook from 1887 was titled "The Gopher Annual" and The Gopher yearbook for 1888 shows the first image of a U of M affiliated Gopher.
Various sports teams at the U were described in local newspapers as the ‘gophers' as early as 1901. Football coach Clarence "Biggie" Spears gets the official credit from the U for calling his 1926 team the "Gophers". While it seems certain that teams before 1926 had been known as the gophers, I'm not going to cast shade on Biggie.
One quick note about why Goldy is golden. In 1934 Bernie Bierman, trying to gain a competitive advantage (like he needed it) changed the teams jerseys to match the color of the football; gold. Legendary journalist Hasley Hall caught on and coined the term "Golden Gophers".
In the 1940s the U of M commissioned George Grooms an Iowa native (smdh) to draw an official mascot for marketing. And thus guy was born. Here is a bit I wrote about the earliest known photo of Goldy.
Various versions of your favorite mascot would appear over the years but Goldy got his name (he had been ‘Goldie' before) and a visual update in 1979 when the Alumni Association hired Bill Grooms the guy who did the Hamms Beer ad's to re-do Goldy.
When Lou Holtz came to the U in 1984, the University hired Jostens (?!?) to redesign the Goldy, and he really hit the weight room. However ‘Evil Goldy' / ‘Angry Goldy' or ‘Poor Orthodontia Goldy' only stuck around for a year. After the three players on the U of M basketball team were accused of rape the U tried to clean up its image (I know that story doesn't really make sense, but it also sounds exactly like something the U of M would do). Also relevant is that Jostens holds the copyright over Angry Goldy, so the U of M cannot use him on any merch or uniforms today. Sad.
The result is the current Goldy.
Goldy the mascot has an equally dramatic evolution beginning in the 1950s, you can read about it here (which is taken from the book the U of M Marching Band Centennial Book, Minnesota Hats Off to Thee, and is almost word for word Goldy's Wikipedia page...) and look at these awesome old mascot pics...
You can also browse the facebook album put together by the U with some great mascot pictures from days of yesteryear.