Before Nellie was given the "official mascot" title, JU went more than 30 years without an official mascot. In 1947, years before Jacksonville Junior College became Jacksonville University, a contest was held to stimulate school spirit and to choose a nickname for the College's newly-organized basketball team. Numerous names were suggested, including Green Raiders, Buccaneers, Juggernauts and Green Dragons, but on Dec. 12, 1947, the winner, Green Dolphins, was announced. It was later shortened to Dolphins.

It was said that the name Dolphins seemed particularly appropriate for JU because of the University's proximity to the Atlantic Ocean and because dolphins actually swim in the St. Johns River, which traverses along the JU campus. Further, the dolphin (usually called porpoise to distinguish it from the popular sport fish) is a highly intelligent mammal that is noted for its speed and sleek appearance.

To date, JU is one of only five colleges or universities - California State-Channel Islands, College of Staten Island (N.Y.), Le Moyne College (N.Y.) and College of Mount St. Vincent (N.Y.) - to sport the Dolphin moniker, while the only professional organization with the Dolphins nickname is the Miami Dolphins. However, JU is the first of all the teams to select Dolphins as its official nickname and mascot.