An Apology to Elephants is a 2013 documentary that explores abuse and brutal treatment of elephants. It showcases elephant training and the psychological trauma and physical damage done by living conditions in some zoos and circuses. It was premiered on HBO on April 22, 2013, also celebrated as an Earth Day. The documentary includes interviews with environmental activists and biologists, including Performing Animal Welfare Society co-founders Ed Stewart and Pat Derby. The film was dedicated to Derby, also known as an "elephant lady", who died on February 15, 2013.Narrator Lily Tomlin campaigned on the subject for several years, in the course of which she met Pat Derby. Later, she suggested that HBO make a movie about elephant captivity. HBO began work on the documentary in 2011. It was later joined by PETA, which offered pictures and video footage, including photos from a whistleblower depicting elephant training at the Ringling Bros circus.