Bison along the Bitterroot Valley's Eastside Highway north of Stevensville, Montana, are covered in snow following a blizzard on November 23, 2010. (Photo by Perry Backus/The Missoulian)

A fighter jet flies above as Ukrainian soldiers sit on an armoured personnel carrier in Kramatorsk, in eastern Ukraine April 16, 2014. Ukrainian government forces and separatist pro-Russian militia staged rival shows of force in eastern Ukraine on Wednesday amid escalating rhetoric on the eve of crucial four-power talks in Geneva on the former Soviet country's future. (Photo by Marko Djurica/Reuters)

A shoebill is displayed at Ueno Zoo in Tokyo August 28, 2012. (Photo by Itsuo Inouye/Associated Press)

A Monster Jam truck performs a back flip during the first-ever monster truck event in Beijing's iconic “Bird's Nest” National Stadium on Saturday, July 29, 2017. (Photo by Ng Han Guan/AP Photo)

American actress Paris Jackson pulls faces at photographers during the “Melbourne Cup” race day festivities in Melbourne, Australia on November 7, 2017. (Photo by Media-Mode/Splash News and Pictures)

Bella Hadid arriving at her hotel on December 7, 2017 in London, England. (Photo by Palace Lee/PacificCoastNews)

A person waits outside fashion show of designer Marina Hoermanseder at the Berlin Fashion Week Autumn/Winter 2018 in Berlin, Germany, January 18, 2018. (Photo by Hannibal Hanschke/Reuters)

Minnie Mouse, left, and Katy Perry attend a ceremony honoring Minnie with a star on the Hollywood Walk of Fame on Monday, January 22, 2018, in Los Angeles. (Photo by Mario Anzuoni/Reuters)