Humboldt Penguins swim in their pool as a keeper looks on through a spherical window during the annual stocktake press preview at London Zoo in Regents Park in London Monday, January 4, 2016. A requirement of ZSL London Zoo's license, the annual audit takes keepers a week to complete and all of the information is shared with zoos around the world via the International Species Information System, where it's used to manage the worldwide breeding programmes for endangered animals. (Photo by Alastair Grant/AP Photo)

A photographer in Somerset, South West England captured the mating rituals of toads as several males attempt to mate with one female all at once. (Photo by John Waters/NPL)

A brown-hooded kingfisher sits on a branch with a freshly caught frog in it's beak. Riaan Marais who took the photo said, “We were doing a boat safari on the Rufiji river in Selous Game Reserve, Tanzania when I spotted the bird with the frog on an overhanging branch on the river bank. It most probably caught the frog in the reeds along the river’s edge as this is where these frogs stay. The kingfisher must have caught the Common Reed Frog just before I took the image, as the frog was still alive, I had a brief moment to take the image before the bird flew off with the frog”. (Photo by Riaan Marais/Solent News and Photo Agency)

People watch police destroy confiscated illegal firecrackers in Shenyang, Liaoning province, China, January 29, 2016. (Photo by Reuters/Stringer)

Rockhopper penguins live up to their name as they navigate the rugged coastline of Marion Island in the southern Indian Ocean. (Photo by Thomas P. Peschak)

A great crested grebe feeds a chick sitting on its mother’s back on a lake in Cáceres, Spain. (Photo by Jose Luis Ruiz/Solent News & Photo Agency)

Visitors hold ice blocks to cool themselves in hot weather at a water park on June 23, 2016 in Chongqing, China. Citizens and visitors escaped high temperature at a water park in Yangren Jie (also known as Foreigner Street), Nan'an District of south China's Chongqing. (Photo by VCG/VCG via Getty Images)

A Sumatran Tiger looks at visiting children from it's enclosure during the ZSL London Zoo's annual stocktake of animals on January 5, 2015 in London, England. The zoo's annual stocktake requires keepers to check on the numbers of every one of the 800 different animal species, including every invertebrate, bird, fish, mammal, reptile, and amphibian. (Photo by Dan Kitwood/Getty Images)