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

Two chimpanzees share a piece of watermelon at Taronga Zoo on December 23, 2010 in Sydney, Australia. (Photo by Rick Stevens/Taronga Zoo via Getty Images)

A baby bush-baby in a set of scales at London Zoo shortly after birth. (Photo by Fox Photos/Getty Images). 10th August 1938

A little girl takes a picture of a lion in the zoo in Frankfurt, Germany, Tuesday, September 13, 2016. (Photo by Michael Probst/AP Photo)

An Indian Royal Bengal tiger looks on at an enclosure on World Tiger Day at Alipore Zoo, Kolkata, India, 29 July 2019. Kolkata zoo authority added a new Tiger to the zoo for the visitors to mark the Tiger Day. Students of Kolkata are also taking part in an awareness campaign aiming to draw attention to the threats that tigers face due to habitat loss and poaching. (Photo by Piyal Adhikary/EPA/EFE)

Talini (R), a 9-month old 160-pound polar bear cub, swims with her mother Barle at the Detroit Zoo's Artic Ring of Life exhibit August 25, 2005 in Royal Oak, Michigan. Talini's birth was the first polar bear birth at the Detroit Zoo in fifteen years. Her mother Barle was wild born and was rescued by the Detroit Zoo from a circus in Puerto Rico in 2002. (Photo by Bill Pugliano/Getty Images)

Mr. Ben, a pygmy slow loris, is administed anesthetic during one of Bristol Zoo's in-house veterinary clinic routine health check-up and teeth clean as part of the Zoo's standard animal husbandry and welfare procedure at Bristol Zoo on June 18, 2009 in Bristol, England. (Photo by Matt Cardy/Getty Images)

A Chimpanzee is seen with funny expressions at Hanover Zoo on September 27, 2013 in Hanover, Germany. (Photo by Barcroft Media)