A panda bear sits on a logs in a zoo on January 15, 2015 in Hangzhou, China. (Photo by Feature China/Barcroft Media)

A six-year-old acrobat performs on the opening of a tourist festival in Bozhou, Anhui province, China May 3, 2015. (Photo by Reuters/China Daily)

A South China Tiger cub meets public at Guangzhou Zoo on June 22, 2017 in Guangzhou, Guangdong Province of China. Guangzhou Zoo boasts of the successful breeding of South China Tiger cub after 15 years. (Photo by VCG/VCG via Getty Images)

Soldiers, including two recruits who have brought some chickens, at Victoria prepare to board the train for the battle front. (Photo by Hulton Archive/Getty Images)

Commuters hang off a local passenger train in the morning in Colombo, Sri Lanka September 8, 2016. (Photo by Dinuka Liyanawatte/Reuters)

Two cocks are trained for a fight in a village in Nakhon Sawan province, Thailand January 10, 2017. (Photo by Chaiwat Subprasom/Reuters)

Young girls attend a training session in MGFSO Olympic reserve school in Moscow on May 30, 2016. (Photo by Kirill Kudryavtsev/AFP Photo)

Young contortionists practice at a training school in Ulaanbaatar, Mongolia, July 4, 2016. (Photo by Natalie Thomas/Reuters)