In a speech on Monday, Zimbabwean President Robert Mugabe said his compatriots failed to protect Cecil the lion. Tsvangirayi Mukwazhi/AP hide caption

itoggle caption Tsvangirayi Mukwazhi/AP

Cecil the lion is shown walking in Zimbabwe's Hwange National Park in a YouTube video from July 9, 2015. Credit: Bryan Orford Bryan Orford/YouTube hide caption

itoggle caption Bryan Orford/YouTube

M.C. Davis, former gambler and businessman, stands in his 54,000-acre preserve, Nokuse Plantation, in the Florida Panhandle. It's the largest privately owned conservation area in the southeastern United States. Matt Ozug/NPR hide caption

itoggle caption Matt Ozug/NPR

Hudson River view. Brian Mann/North Country Public Radio hide caption

itoggle caption Brian Mann/North Country Public Radio

A tray of sardines in Costa Mesa, California, in this November 17, 2014 photo. Plummeting sardine populations force a complete ban on sardine fishing off the U.S. West Coast for more than a year. LUCY NICHOLSON/Reuters /Landov hide caption

itoggle caption LUCY NICHOLSON/Reuters /Landov

A baby orangutan wearing a diaper swings through the trees at the Sumatran Orangutan Conservation Program outside Medan, capital of Indonesia's North Sumatra province. The program takes mostly orphaned orangutans, nurses them back to health and releases them back into the wild. Anthony Kuhn/NPR hide caption

itoggle caption Anthony Kuhn/NPR

Volunteer Tom Strain carries debris from an empty lot as part of an Earth Day cleanup effort in Camden, N.J. The Earth Day events celebrated on April 22 promote a sustainable and clean environment. Mel Evans/AP hide caption

itoggle caption Mel Evans/AP