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)

Individuals and populations student winner. Limbing in the Tropics, photographed in Manaus, Brazil. While walking in the Amazon rainforest looking for bat roosts to set up mist nets to capture bats for scientific research, a faint and almost imperceptible noise suddenly caught this photographer’s attention. An anteater was climbing with exceptional ability in a tangled mess of branches and lianas. (Photo by Adrià López Baucells/University of Lisbon/British Ecological Society)

The National Geographic Photo Ark is a travelling exhibition of photographer Joel Sartore’s quest to create a photo archive of biodiversity around the world. So far, Sartore has captured studio portraits of more than 6,000 species – a number that he hopes to double. On 1 July, the ark will open at Melbourne zoo – the first time it has been exhibited in the southern hemisphere. More than 50 portraits will be on display, including many of Australian endangered animals being protected by programs at the zoo itself. These captions have been edited from text supplied by Melbourne zoo. Here: Barking owl. (Photo by Joel Sartore/National Geographic Photo Ark/The Guardian)

In this May 4, 2014 photo, a miner holds an amalgam of mercury and gold he mined after working a 28-hour shift at an illegal gold mining process, in La Pampa, in Peru's Madre de Dios region. Thousands of artisanal gold miners sweat through the long shifts and endure, for a few grams of gold, the perils of collapsing earth, limb-crushing machinery and the toxic mercury used to bind gold flecks. (Photo by Rodrigo Abd/AP Photo)

Layers of breathtaking colour streak the rolling hills of this vast desert, making the landscape appear as though it has been tie-dyed. The natural phenomenon, nicknamed the “Painted Desert”, was formed when the area was once a river floodplain. Each colour corresponds to a different underground geological feature – rocks which have seemingly dyed the layers of earth above. Formed from volcanic activity, the hills at the John Day Fossil Beds National Monument in East Central Oregon, USA, are almost bursting with colour. Pictured: The colourful hills at the John Day Fossil Beds National Monument in East Central Oregon, USA. (Photo by Mark Brodkin/Solent News/SIPA Press)

A Funnel Web spider is pictured at the Australian Reptile Park January 23, 2006 in Sydney, Australia. The Funnel Web is one of Australia's deadliest animals, with a venom that is packed with at least 40 different toxic proteins. A bite from a Funnel Web causes massive electrical over-load in the body's nervous system. Finally, fatalities occur from either heart attack or a pulmonary oedema, where the capillaries around the lungs begin to leak fluid and the patient effectively drowns. Death can come as quickly as two hours after a bite if no medical treatment is sought. Due to advances in anti-venom, there has been no death from a Funnel Web bite in Australia since 1980. Australia is home to some of the most deadly and poisonous animals on earth. (Photo by Ian Waldie/Getty Images)

Back dropped by planet Earth the International Space Station (ISS) is seen from NASA space shuttle Endeavour after the station and shuttle began their post-undocking relative separation May 29, 2011 in space. After 20 years, 25 missions and more than 115 million miles in space, NASA space shuttle Endeavour is on the last leg of its final flight to the International Space Station before being retired and donated to the California Science Center in Los Angeles. Capt. Mark E. Kelly, U.S. Rep. Gabrielle Giffords' (D-AZ) husband, has lead mission STS-134 as it delivered the Express Logistics Carrier-3 (ELC-3) and the Alpha Magnetic Spectrometer (AMS-2) to the International Space Station. (Photo by NASA via Getty Images)