Children feed a giraffe at Pairi Daiza wildlife park, a zoo and botanical garden in Brugelette, Belgium, May 25, 2015. (Photo by Francois Lenoir/Reuters)

A chevrotain or mouse deer feeds in its enclosure at Zurich Zoo, Zurich, Switzerland, October 17, 2012. (Photo by Patrick B. Kraemer/AP)

A chimpanzee feeding a leopard cub at Southam Park Zoo, Warwickshire. (Photo by Ian Tyas/Keystone Features/Getty Images). 1971

Children feeding the birds in this Victorian Christmas greetings card. (Photo by Hulton Archive/Getty Images). Circa 1885

Beryl Lipton, left, douses Matt Lee during the ice bucket challenge at Boston's Copley Square, Thursday, August 7, 2014 to raise funds and awareness for ALS. The idea is: pay up for charity or get doused. The fund-raising phenomenon is catching on fast, propelled by popular videos of the dunkers and the dunked – including famous athletes and entertainers – posted on social media sites. And the challenges are raising tens of thousands of dollars and immeasurable awareness for causes from ALS to breast cancer to a camp for kids who've lost a father to war. (Photo by Elise Amendola/AP Photo)

A visitor feeds a food pellet to a giraffe in the Giraffe Centre in Nairobi, Kenya January 15, 2017. (Photo by Goran Tomasevic/Reuters)

A visitor feeds a food pellet to a giraffe in the Giraffe Centre in Nairobi, Kenya January 15, 2017. (Photo by Goran Tomasevic/Reuters)

A leopard seal feeds Paul Nicklen a penguin. (Photo by Paul Nicklen/National Geographic). Antarctic Peninsula, 2011