Louis E. Pratt, master ivory cutter for Pratt, Read & Co., shows off eight ivory tusks, April 1, 1955. Courtesy of Deep River Historical Society hide caption

itoggle caption Courtesy of Deep River Historical Society

An elephant in Kenya's Tsavo East National Park, home to some 13,000 of these remarkable animals. Ivan Lieman/AFP/Getty Images hide caption

itoggle caption Ivan Lieman/AFP/Getty Images

An elephant at the Emmen, Netherlands, zoo stands at the edge of a ditch in 2009, a day after another elephant fell into the ditch and died. Olaf Kraak/AFP/Getty Images hide caption

itoggle caption Olaf Kraak/AFP/Getty Images

The arrival of African elephants at a Tucson zoo prompted a call for the zoo's fans to contribute leafy snacks. This file photo shows African elephants at the Pittsburgh Zoo & PPG Aquarium in 2011. Gene J. Puskar/AP hide caption

itoggle caption Gene J. Puskar/AP

A family of elephants in Kenya's Maasai Mara game reserve. Tony Karumba/AFP/Getty Images hide caption

itoggle caption Tony Karumba/AFP/Getty Images