Doug Terranova said Thursday that he reached the agreement to leave with Executive Zoo Director Greg Hudson after reports about his case attracted negative publicity.
In 2010, the zoo purchased two elephants from Terranova and he began working at the zoo to contribute to their care.
In February, NBCDFW reported on the federal case accusing Terranova of mistreating those elephants and other animals in the past, which he denies.
Terranova has worked in circuses and as an animal trainer for television and movies.
But Terranova said Thursday that publicity bout his case had become a distraction for the zoo and that members of the Zoo Society board were asking questions.
“If it hurts their ability to raise money to care for the elephants, that is not good,” Terranova said.
Here is the official statement from the Dallas Zoo:
"Typically, the Dallas Zoo does not comment on personnel issues, but Mr. Terranova asked us to relay that he believes that Congo and Kamba are healthy and thriving in their new habitat and have successfully transitioned to their new home. That, coupled with the fact that he is very distracted with some issues in his business and personal life, made now a good time for him to resign and focus on his business and personal issues. He stated that he did not want his personal and business issues to be a distraction to the Zoo."
A hearing on the federal complaint began last month and will continue in the near future.
Terranova said a final ruling in the U.S. Department of Agriculture case may come this fall.