The group also said it was demanding that the country's only other zoo that houses the elephant breed do the same.
The 42-year-old elephant, named Charlie, was removed from the national zoo in Pretoria and transported to a reserve in the northern province of Limpopo, where it was released on August 19 by the EMS Foundation.
This followed years of negotiations with the South African government, which was provided with scientific evidence that elephants were suffering in zoos, the foundation said in a statement.
Captured from his herd in Zimbabwe when he was about 2 years old, Charlie was sold to a circus to perform tricks, and was moved to the Pretoria Zoo in 2001.
"The science is clear that elephants are defined by space and should not be in captivity," said executive director Michelle Pickover.
The only other zoo in South Africa with elephants is the Johannesburg City Zoo, which has 3. We are taking legal action against Johannesburg for them. Charlie's release doesn't necessarily mean that the government has decided to stop all elephant exhibits in its zoos, but it seems there are no plans to get more," she added. | BGNES