The fourth annual BigPicture Natural World Photography Competition aims to celebrate the diversity of life on Earth, and encourages people to protect and conserve it. Here: “The Salmon Catchers”. Terrestrial Wildlife. To capture this view of a mother grizzly bear and her cub, photographer Peter Mather set up a camera trap on a log that he knew the bears tended to traverse while fishing for salmon, in the Yukon River watershed in Canada. (Photo by Peter Mather/BigPicture Natural World Photography Competition 2017)

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)

A man walks with a Cyberdog, produced by Chinese tech company Xiaomi, on February 19, 2022 in Beijing, China.The quadruped robots, often owned by tech and robotic enthusiasts, do not have a specific purpose so far, but the open source nature of the robots could make them suitable for several applications in the future. (Photo by Andrea Verdelli/Getty Images)

A recently hatched baby Egret bird seen in a nest at the Gatorland Bird Rookery in Kissimmee, Florida on March 17, 2022. Gatorland is known as The Alligator Capital of the World and has a 10 acre natural bird rookery. (Photo by Ronen Tivony/SOPA Images/Rex Features/Shutterstock)

Wildlife agency rangers rescue a Malayan tapir, an endangered species on the International Union for Conservation of Nature (IUCN) Red List, after it fell into a villager's fish pond in Pekanbaru, Riau on April 20, 2021. (Photo by Wahyudi/AFP Photo)

A lynx cub that followed a villager in the forest, is fed by a mother and her son for 2 days at the Koyulhisar district of Sivas, Turkiye on October 4, 2023. After 2 days, the lynx cub was taken under protection by the Sivas Department of Nature Conservation and National Parks teams. (Photo by Serhat Zafer/Anadolu Agency via Getty Images)

Tuvalu-registered OS 35 cargo ship lies on the seabed, offshore Gibraltar, Tuesday, August 30, 2022. Gibraltar authorities say they have beached a cargo ship to prevent it from sinking after it collided with a liquefied natural gas carrier in the bay of Gibraltar. (Photo by Europa Press via AP Photo)