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)

Well before Corey Arnold ever thought about photography, he fished. As a child, he dressed as a fisherman for four consecutive Halloweens, and once brought a dead 3-foot Mako shark to school for show-and-tell. He knew he wanted to be a professional fisherman, even if he didn’t understand what that actually meant.

An amazing artist transforms scrap metal into incredible sculptures of insects, birds, fish, and other animals. Edouard Martinet from Brittany, France, creates the sculptures from all manner of salvaged parts and junk, including car and bicycle parts, typewriters, and medical equipment. Photo: An ant by Edouard Martinet. (Photo by Edouard Martiniet/Caters News)

Kambeba Indian, Dream Braga, 18, aims his arrow in a jungle near the village Tres Unidos, Amazon state May 9, 2015. Dream Braga has been shooting fish with a bow and arrow for most of his life. In the Amazonian village where he grew up, that was what kids did for food and fun. He participated in the Indigenous Archery Project which recruits Amazon native children to compete with modern archery equipment and try for a place on the national team, with the 2016 Olympics in Rio de Janeiro as their ultimate goal. After training with Olympic coaches for three months, he has now been promoted to Brazil's national team. (Photo by Bruno Kelly/Reuters)

The President of the sushi restaurant chain Sushi Zanmai, Kiyoshi Kimura, cuts a blue fin tuna outside his main restaurant at the outer Tsukiji market in Tokyo January 5, 2015. The 180 kg blue fin tuna traded at a price of 4.5 million yen (37,500 USD) and was the most expensive fish at this year's New Year auction at the Tsukiji market, local media reported. (Photo by Thomas Peter/Reuters)

Model, skydiver and wing-suit jumper Roberta Mancino, 33, swims with a whale shark on February 2014 in Isla Mujeres, Mexico. A female skydiver swims with whale sharks, manta rays and sailfish – the fastest fish in the sea. Model, skydiver and wing-suit jumper Roberta Mancino, 33, jumped from a boat into the ocean surrounding Isla Mujeres near the northern Peninsula of Mexico. The incredible project involved two trips to the stormy winter seas – one in February 2013 and one a year later in February 2014. (Photo by Shawn Heinrichs/Barcroft Media)

Folk artist Han Xiaoming demonstrates painting with his tongue in Hangzhou, Zhejiang province December 4, 2014. Han dips his tongue in ink to paint on paper, and uses his fingers to fill in final adjustments. The artist also uses a paintbrush held with his mouth and utilizes fish and vegetables as paint tools, local media reported. (Photo by Aly Song/Reuters)