"The first reference to "Who Dat?" can be found in the 19th Century in the poetry of Paul Laurence Dunbar, first in his poem "When Malindy Sings" and later in his lyrics to the song "Who Dat Say Chicken in dis Crowd," a featured song in E.E. Rice's "Summer Nights," in a show called Clorindy: The Origin of the Cake Walk by Will Marion Cook. A common tag line in the days of Negro minstrel shows was: "Who dat?" answered by "Who dat say who dat?" Many different blackfaced gags played off that opening. Vaudeville performer Mantan Moreland was known for the routine. Another example is "Swing Wedding," a 1930s Harman-Ising cartoon musical, which caricatured Fats Waller, Cab Calloway, Bill "Bojangles" Robinson, Ethel Waters, and the Mills Brothers as frogs in a swamp performing minstrel show jokes and jazz tunes. The frogs repeatedly used the phrase "who dat?"
In the swing era, "who dat" chants back and forth between the band and the band leader or between the audience and the band were extemporaneous. That is, there was no one specific set of words except for the two magic ones.
"Who Dat?" lyrics from 1937:
Who dat up there who’s dat down there
Who dat up there who dat well down there
Who’s dat up there, sayin’ who’s dat down there
When I see you up there well who’s dat down there Who dat inside who’s dat outside
Who’s dat inside who dat well outside
Who’s dat inside, singin’ who’s dat outside
When I see up there well who’s dat out there Button up your lip there big boy
Stop answerin’ back
Give you a tip there big boy
Announce yourself jack Who dat up there who’s dat down there
Who dat up there who dat, well down there
Who’s dat up there, singin’ who’s dat down there
When I see you up there you bum
Well who’s dat down there Who dat
Staged minstrel skits featured frightened African-American characters saying "who dat" when they encountered a ghost, or someone imitating a ghost. Then, the "who dat"-"who dat say who dat" skit would play itself out. This skit was done frequently in short reels from the 1930s to 1950s and in some early TV shows too. Even the Marx Brothers had a "who dat" routine, which they included in their film A Day at the Races. Often, a ghost was called a "who dat". MGM's now-banned animated character Bosko once had such an encounter in a 1938 toon called "Lil Ol Bosko in Bagdad"."
To have a trademark one most show first use and in fact use and defend the trademark. If it is not first use and defended it is not valid.
The New York Times did a list of who has used "Who Dat", in songs and movies at http://www.newyorker.com/online/blogs/closeread/2010/02/the-strange-case-of-who-dat.html
"In other words, Who Dat had developed a life that wasn’t attached to Hollywood or the Casino Roof Garden. (And all this should make the absurdity of the N.F.L.’s attempt to assert its copyright over the phrase abundantly clear, if it wasn’t already.) The first Lousiana football games it was chanted at seem to have been high school games. TheTimes-Picayune says that the credit has gone both to the Patterson Lumberjacks (“Who dat? Who dat? Who dat say they’re going to beat those ‘Jacks’ ”) and the Saint Augustine Purple Knights in New Orleans (“Who dat? Who dat? Who dat talk about beat St. Aug?”)
Read more http://www.newyorker.com/online/blogs/closeread/2010/02/the-strange-case-of-who-dat.html#ixzz108RGTKZx"
Yet now we have another group claiming to own "Who Dat" and charging $500 plus 10% for its use. Even with a US Senator saying that they need to sue him to stop him from useing "Who Dat" on his shirts.
"U.S. Sen. David Vitter is taunting the latest group to claim ownership of the phrase "Who Dat," sending a letter that tells the company to drop its trademark lawsuit or meet him in court.Vitter jumped into the fray over the popular Saints chant by sending two of his T-shirts to the owners of the company, "Who Dat? Inc." The T-shirts, printed earlier this year when the NFL asked shop owners to stop selling Who Dat merchandise, say "Who Dat say we can't print Who Dat! © TM 2010 David Vitter (just kidding)""You're kidding, right? Claiming you own the legal rights to the term 'Who Dat'?" Vitter wrote in his letter to the company."
Read more at-http://www.wdsu.com/news/25083376/detail.html
With all of the threats of lawsuits most of us avoid using Who Dat but here are a few shirts.
And some with other phrases.