A staff interacts with a white lioness in a private zoo called “12 Months” in the town of Demydiv, Ukraine, January 13, 2016. (Photo by Gleb Garanich/Reuters)

Five micropigs born to mother, “Truffel”, are seen in Zoo Wuppertal on August 11, 2014 in Wuppertal, Germany. The five micropigs are the major attraction of Zoo Wuppertal. Pigedy, Fiete, Frederik, Smartie are 4 males and is Keks is a female micropig. (Photo by Animal Press/Barcroft Media)

A life size animatronic Tyrannosaurus Rex dinosaur arrives at Bristol Zoo Gardens on May 14, 2012 in Bristol, England. Twelve animatronic dinosaurs arrived at Bristol Zoo Gardens this morning after being transported in crates from Texas, USA. They will form part of the zoo's summer exhibition “DinoZoo” which opens later this month. (Photo by Matt Cardy)

Visitors look at a plastinated gorilla on the opening day at the Body World Animals exhibition at the Cologne Zoo on April 15, 2011 in Cologne, Germany. The exhibition is by Gunther von Hagens, who uses a special process to preserve real bodies, whether animal or human, in order to display the inner organs, muscles and other physical elements. The exhibition will be open to the public until September 30.

Zookeeper Michael Horn holds up Kit and Kitty, the twin red pandas born in June on the first day of their introduction into their new enclosure at Tierpark Zoo on September 13, 2011 in Berlin, Germany. The red panda (Ailerus fulgens) is a rare mammal native to the eastern Himalayas and southwestern China. (Photo by Sean Gallup/Getty Images)

A penguin swims in its enclosure during a photocall to promote London Zoo's annual stock take of animals on January 4, 2012 in London, England. The zoo's stocktake takes place annually, and gives keepers a chance to check on the numbers of every one of the animals from stick insects and frogs to tigers and camels. (Photo by Dan Kitwood/Getty Images)

A Common Blue Morpho butterfly lands on the arm of Garbiella as it and hundreds of other butterflies from around the world fill the bird aviary for the next month at the San Diego Zoo Safari Park in San Diego, California March 13, 2015. Called the Butterfly Jungle, the exhibit has over 30 species of butterflies. (Photo by Mike Blake/Reuters)

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)