A newly born Indian white tiger cub yawns in its enclosure at Liberec Zoo, Czech Republic, April 25, 2016. (Photo by David W. Cerny/Reuters)

Squirrels are seen on a tree branch at a park as temperatures rise with the arrival of spring season in Ankara, Turkiye on March 27, 2024. (Photo by Evrim Aydin/Anadolu via Getty Images)

A staff member sets up a ROBOTLEO robot at the Global Mobile Internet Conference (GMIC) 2017 in Beijing, China April 28, 2017. (Photo by Jason Lee/Reuters)

A hippopotamus performs during a show at the circus in Krasnoyarsk, Siberia, Russia, July 7, 2016. (Photo by Ilya Naymushin/Reuters)

Sandra, a 29-year-old orangutan at Buenos Aires' zoo, on May 20, 2015. Sandra got cleared to leave a Buenos Aires zoo that was her home for 20 years, after a court ruled she was entitled to more desirable living conditions. (Photo by Juan Mabromata/AFP Photo)

In a new project, an international group of photographers have joined forces to use their powerful images to raise awareness and funds to help stop the illegal wildlife trade. Here: Fennec foxes are captured for the illegal pet trade. This three-month-old pup was for sale in a market in southern Tunisia. (Photo by Bruno D'Amicis/Photographers Against Wildlife Crime/Wildscreen/The Guardian)

Guanacos sit during a signing ceremony in Patagonia Park, Chile, January 29, 2018. Chilean President Michelle Bachelet signed decrees Monday creating vast new national parks using lands donated by U.S. conservation organization Tompkins Conservation in what is believed to be the largest private donation of land ever from a private entity to a country. (Photo by Esteban Felix/AP Photo)

Global wildlife populations will decline by 67% by 2020 unless urgent action is taken to reduce human impact on species and ecosystems, warns the biennial Living Planet Index report from WWF (World Wide Fund for Nature) and ZSL (Zoological Society of London). From elephants to eels, here are some of the wildlife populations most affected by human activity. Here: The maned wolf is among the large mammals in the Brazilian Cerrado that are threatened by the increasing conversion of grasslands into farmland for grazing and growing crops. (Photo by Ben Cranke/Nature Picture Library/Alamy Stock Photo)