Smithsonian National Zoo biologist Leigh Pitsko releases a male lion cub for its swim test in the zoo habitat moat, in Washington May 6, 2014. Four, unnamed ten-week old lion cubs were tested today for their ability to swim and remove themselves from their zoo habitat moat. (Photo by Gary Cameron/Reuters)

A woman photographs “Super Space Titan Kitty” by Colin Christian at the “Hello! Exploring the Supercute World of Hello Kitty” museum exhibit in honor of Hello Kitty's 40th anniversary, at the Japanese American National Museum in Los Angeles, California October 10, 2014. (Photo by Lucy Nicholson/Reuters)

In this February 2, 2014 photo, people take pictures inside a cave at Apostle Islands National Lakeshore in northern Wisconsin, which has been transformed into a dazzling display of ice sculptures by the arctic siege gripping the Upper Midwest. (Photo by Brian Peterson/AP Photo/Minneapolis Star Tribune)

HRP-4C, a five-foot humanoid robot developed at Japan's National Institute of Advanced Industrial Science and Technology, sings and dances with performers at the Digital Contents Expo in Tokyo on October 17, 2010. The robot runs entertainment software called Choreonoid, a name formed from the words “choreograph” and “humanoid”. (Yoshikazu Tsuno/AFP)

North Korean youngsters sing and play accordions to entertain foreign visitors including United Nations Secretary General Kurt Waldheim, who visited Pyongyang, May 4, 1979. Visitors report music education in North Korea begins at an early age and is taken seriously by children and adults. (Photo by Peter Arnett/AP Photo)

Daisuke Nagasawa, 49, has spent the past few years taking his two faithful cats, Daikichi and Fuku-Chan, around the world with him. Here: Daisuke Nagasawa travels nationally and internationally with his beautiful kitties Fuku-Chan and Daikichi. The two pose under the iconic Japanese cherry blossoms. (Photo by Daisuke Nagasawa/Caters News Agency)

On Guard, Indonesia, by Riksa Dewantara. The explosive eruption and loud rumbling of the Mount Bromo volcano in Bromo Semeru Tengger national park scared the horse causing it to rear up onto its hind legs. Second place, Journeys and Adventures category. (Photo by Riksa Dewantara/SIPA Contest)

A ranger watches a seal pup near the Northumberland coast, Farne Islands, UK on December 19, 2018, where the National Trust says the number of Atlantic grey seal pups has reached a record high thanks to an abundance of food and a lack of predators. (Photo by Owen Humphreys/PA Wire Press Association)