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)

Australian performers illuminated with real clocks titled “The Time Minder” attend a media preview of the Night Festival in Singapore on August 23, 2017. Singapore's arts and heritage district will be transformed into Singapore largest outdoor performing arts festival to celebrate its 10th year edition Night Festival from August 24 to 26. (Photo by Roslan Rahman/AFP Photo)

A boy covers his head with fallen leaves as he enjoys a stroll with his family in a park in downtown Frankfurt, Germany, November 6, 2016. (Photo by Kai Pfaffenbach/Reuters)

Meropidae are seen on a rock in Van in Turkey on March 03, 2018. (Photo by Ali Ihsan Ozturk/Anadolu Agency/Getty Images)

A Chinese tourist uses the scarf of a friend as she is helped while she and others struggle to climb in the wind on an icy section of the Great Wall at Badaling, on a cold day after a snowfall on November 30, 2019 in Beijing, China. (Photo by Kevin Frayer/Getty Images)

A hiker walks in the Zillertal Alps during an autumn day near the village of Ginzling, Austria, October 15, 2019. (Photo by Lisi Niesner/Reuters)

An otter reaches for a snack from a customer at an otter cafe in Tokyo. Asian small-clawed otters are increasingly popular as novelty pets, particularly in Japan. Now international trade in the species may be banned. (Photo by Noriko Hayashi/The New York Times)