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)

A hyena cub got a mouthful from his mum after it appears he got a right telling off. Michael Raddall, a animal enthusiast and wildlife photographer from South Africa, snapped the mum and cub at the Timbavati game reserve in South Africa while on safari at the Umlani Bush camp. (Photo by Michael Raddall/Caters News Agency)

A boy rides on a snow wagon towed by a robot dressed as a Teddy bear, which only moves forward by moving its legs, during the Ice and snow carnival at Taoranting park in Beijing February 9, 2015. (Photo by Kim Kyung-Hoon/Reuters)

A bride and groom jump over a skipping rope as they pose during a wedding photo shoot at a park in Pyongyang on April 18, 2019. (Photo by Ed Jones/AFP Photo)

A Sphynx cat at the 2017 Grand Prix Royal Canin international cat show at the Crocus Expo Exhibition Centre in Moscow, Russia on December 2, 2017. (Photo by Sergei Savostyanov/TASS/Barcroft Images)

A nurse holds a painting of Prime Minister Boris Johnson clapping with blood on his hands as part of a demonstration of NHS workers at hospitals across London to demand a 15 per cent pay rise by the government in London, Wednesday, August 26, 2020.(Photo by Kirsty Wigglesworth/AP Photo)

An officer from the California Department of Fish and Wildlife gets ready to tranquillize a bear in Pasadena, California, U.S., August 20, 2021. (Photo by Mario Anzuoni/Reuters)

A heat-stressed koala waits as a resident pours water on its back on December 19, 2015 in Adelaide, Australia. Adelaide is experiencing an extreme heatwave, with temperatures reaching over 40 degrees for five consecutive days. (Photo by Morne de Klerk/Getty Images)