A donkey savors warming temperatures after a long winter at the zoo in Warsaw, Poland, on Wednesday, April 8, 2015. (Photo by Czarek Sokolowski/AP Photo)

Indonesian mahouts clean their Sumatran elephant in a river near the zoo in Medan, North Sumatra, Indonesia, 12 December 2014. According media reports, the smallest of the Asian elephants, Sumatran elephant (Elephas maximus sumatrensis) is facing serious pressures arising from illegal logging and associated habitat loss and fragmentation in Indonesia. The population has come under increasing threat from rapid forest conversion to plantations. (Photo by Dedi Sahputra/EPA)

A toddler held by her father swims underwater during a swimming class for babies at Lane Cove pool February 16, 2007 in Sydney, Australia. (Photo by Ian Waldie/Getty Images)

A Selkirk Rex cat is one of more than 400 breeds of cats being presented at the World Cat Federation two-day show in Dortmund, Germany, on April 21, 2013. (Photo by Frank Augstein/Associated Press)

An adorable baby owl has proved to be a real heart-breaker thanks to its heart-shaped head. Although Griffin the Lesser Sooty Owl might look like a feather duster, the tiny eight-week old chick will soon be ready to fly. And the heart outline that surrounds his giant eyes and beak means he is set to be the star of the bird show at Taronga Zoo, Sydney. (Photo by Caters News Agency)

Two keepers at the Australian Reptile Park in New South Wales struggle with Leonardo, an alligator snapping turtle weighing 45 kilos at the park in Gosford, NSW 2 July 2015. The 50cm long Leonardo – who was smuggled illegally into Australia and found in a Sydney sewer in November 2000 – was removed from his tank for an annual health check. And as a gesture to onlooking press photographers demonstrated his strength by snapping a piece of bamboo in half. (Photo by EPA/HO)

A devotee carrying an idol of the Hindu god Ganesh, the deity of prosperity, jumps into the Sabarmati river to immerse the idol during the 10-day-long Ganesh Chaturthi festival in Ahmedabad, India, September 11, 2016. (Photo by Amit Dave/Reuters)

This bat gives a cheeky smile as he gobbles down his food at Singapore Zoo, on September 10, 2013. (Photo by Benny Iskander/HotSpot Media)