A child looks at a polar bear swimming under a water in its enclosure on a hot summer day at Prague Zoo, Czech Republic, July 30, 2015. (Photo by David W. Cerny/Reuters)

Light sculptures glow in the dark at the zoo in Cologne, Germany, 04 December 2019. The artworks are on display at the zoo as part of the China Light Festival that runs until 09 January 2020 and features more than 70 light installations on the zoo grounds. (Photo by Sascha Steinbach/EPA/EFE)

A newly-born male baby elephant, who so far does not have a name, walks with his mother Temi during his first venture outside at their enclosure at the Tierpark Hellabrun zoo on May 12, 2011 in Munich, Germany. The baby elephant was born at the zoo on May 6. (Photo by Alexander Hassenstein/Getty Images)

A three month-old baby gorilla named Hasani sits in the grass March 11, 2009 at the San Francisco Zoo in San Francisco, California. The newborn gorilla was given the name Hasani. Hasani's father, a twenty seven year-old gorilla named Oscar Jonsey, picked between five color coded cantaloupes representing the five name finalists to come up with the newborn's name that was submitted by Amanda VerPloeg of Oskaloosa, Iowa. (Photo by Justin Sullivan/Getty Images)

A baby hippopotamus lies next to its mother on the first day it was presented to the public at the Zoo Berlin zoo on November 1, 2011 in Berlin, Germany. The baby hippo was born at the zoo on October 23. (Photo by Sean Gallup/Getty Images)

Radin the Sunda pangolin hitches a ride on Nita as their keeper looks on. The elusive and nocturnal Sunda pangolin produces only one or two offspring a year and Radin is the third pangolin baby born in Night Safari since 2011. (Photo by Wildlife Reserves Singapore)

A polar bear cub snuggles up against her mother Valeska, in their enclosure at Bremerhaven's (Bremen's) Zoo by the Sea, Germany March 9, 2016. The female cub, who is yet to ne named, was born on December 11 last year. (Photo by Carmen Jaspersen/Reuters)

Nuninka, Bornean orangutan (Pongo pygmaeus), holds her newborn baby in the enclosure at Usti nad Labem Zoo, Usti nad Labem, Czech Republic January 3, 2017. (Photo by David W. Cerny/Reuters)