I would love to answer that with full-fledged information, but I'm restricted, so I'll answer the best I can. I belong to an International Orginization who's members are called Turtles, and, there is an appropriate response that Turtle members are schooled in when asked if they're a Turtle as well.
I was inducted last fall, and I agreed to the join request because of the history of the how the orginization came about in the 1940s by a few American USAF pilots stationed in England when moral was very low and allied forces airmen losses were very high.
You can find out more about the orginization via google, under the search of International Order of Turtles, or Orginization of Turtles. The stories about it being ancient are fibs, and a great deal of bigger fibs have been added to it's birth and existence, but it's all been in good fun.