Birds sit on the back of a zebra in the Nairobi National Park, near Nairobi, Kenya, November 21, 2018. (Photo by Baz Ratner/Reuters)

Mini-pigs perform during the presentation in Balashikha, Russia on December 19, 2018. (Photo by Maxim Shemetov/Reuters)

Fishermen catch fish at Mao'er lake at the start of winter fishing season which is a local custom to welcome the new year on December 29, 2018 in Huaian, Jiangsu Province of China. (Photo by VCG/VCG via Getty Images)

Frost covers part of the face of University of Minnesota student Daniel Dylla during a morning jog along Mississippi River Parkway Tuesday, January 29, 2019, in Minneapolis. Extreme cold and record-breaking temperatures are crawling into parts of the Midwest after a powerful snowstorm pounded the region, and forecasters warn that the frigid weather could be life-threatening. (Photo by David Joles/Star Tribune via AP Photo)

A humpead wrasse, transported from Japan's southern island of Okinawa, swims with other tropical saltwater fish on display in a tank for the Sony Aquarium 2017 exhibition in Tokyo on July 31, 2017. The Sony Aquarium 2017 exhibition, featuring marine life common to the waters around Okinawa, runs until August 13. (Photo by Kazuhiro Nogi/AFP Photo)

Aerial view of tourists in life vests and rubber rafts in the Grand Canyon of western Henan, Sanmenxia, China on August 5, 2017. (Photo by Imaginechina/Rex Features/Shutterstock)

A herd of wildebeest cross the skyline against the fading light in Masai Mara, Kenya, 25 August 2017. Stunning sunset photos silhouette Africa’s wildlife against streaks of orange and red sky. In August, German photographer Ingo Gerlach was on safari in the Masai Mara when he convinced his safari guide to stop and take in the sunset. The wildlife photographer was rewarded with his patience by an eye-catching sunset, which cast Africa’s wildlife into dark shadows against the vibrant skies. (Photo by Ingo Gerlach/Barcroft Images)

The aerial view shows three uprooted trees at a road near Hildesheim, Germany Friday, October 6, 2017. Seven people died Thursday as high winds knocked over trees and caused widespread travel chaos in northern Germany. (Photo by Julian Stratenschulte/DPA via AP Photo)