A blind child in Chicago sits on the back of a kneeling elephant from the Ringling Brothers Circus in April 1917. Ringling Bros. will have elephants perform for the final time Sunday, May 1. It had previously said that all of its elephants would be retired by 2018, but the retirement came early. Chicago History Museum/Getty Images

Detective inspector Frank Story, right, euthanized this circus elephant after it was badly burned in a fire at the Ringling Bros. show grounds in Cleveland in August 1942. AP

People stand near a circus elephant during a rehearsal in Sarasota, Florida, in 1949. Nina Leen via Getty Images

Actress Marilyn Monroe rides on the back of an elephant to mark the opening night of the circus at New York's Madison Square Garden in March 1955. ullstein bild via Getty Images

Elephants perform in New York in March 1964. Dave Pickoff/AP

Elephants work out and train in 1971. Duane Howell/Denver Post via Getty Images

Children in Denver react to Charlie the elephant in 1978. John Sunderland/Denver Post via Getty Images

An elephant walks out of a boxcar near the show's famous animal trainer, Gunther Gebel-Williams, in 1979. Duane Howell/Denver Post via Getty Images

Elephants perform in 1995. Visions of America/UIG via Getty Images

This January 2005 photo, provided by the Animal Protection Institute, shows circus elephants chained in Jacksonville, Florida. Feld Entertainment Inc., which produces the Ringling Bros. and Barnum & Bailey Circus, agreed to pay $270,000 for allegedly violating the Animal Welfare Act on several occasions from June 2007 to August 2011, according to a 2011 news release from the U.S. Department of Agriculture. As part of the settlement, the company admitted no wrongdoing or violation of USDA policy. Bradley Stookey/Animal Protection Agency via AP

Nicole, a 31-year-old elephant, shows off her artistic talent in 2006 as she paints for children of the local Ronald McDonald House in New York. Sam Costanza/NY Daily News Archive via Getty Images

Performers ride elephants during a show in New York in April 2007. Scott Wintrow/Getty Images

Animal handlers bathe and brush two elephants in Phoenix in July 2006. Jennifer Grimes/East Valley Tribune via AP

An elephant's trunk is seen on a train before a walk in Washington in 2009. Carol Guzy/The Washington Post/Getty Images