A Humboldt penguin stands on weighing scales whilst being photographed by members of the press during a photocall at the annual weigh-in at London Zoo in London, Britain, 24 August 2016. Every animal that is in the zoo is weighed and measured and the statistics recorded so the data can be shared with zoos across the world. (Photo by Hannah McKay/EPA)

Bjorn, aged 5, smiles as he poses with a Owl butterfly during an event to launch the Sensational Butterflies exhibition at the Natural History Museum in London, Britain March 23, 2016. The exhibition opens to the public on March 24 and runs until September 11. (Photo by Dylan Martinez/Reuters)

A migrant carries his belongings as he arrives at the Beijing railway station to catch a train in Beijing, Friday, February 13, 2015. (Photo by Andy Wong/AP Photo)

A woman toes a tube carrying a man during the Ice and snow carnival at Taoranting park in Beijing, China, January 25, 2016. (Photo by Kim Kyung-Hoon/Reuters)

The king penguin in his moulting suit joins his waddle on their way to the water despite not being waterproof yet at Volunteer Point on the Falkland Islands, 2023. (Photo by Judy Rogero/Media Drum Images)

Revelers throw colored corn starch into the air as they celebrate the 2015 Holi (Festival of Colors) at the Krishna Temple in Spanish Fork, Utah on Saturday, March 28, 2015. (Photo by Rick Bowmer/AP Photo)

Tourists take a “selfie” as demonstrators burn a trash container during a May Day rally in Barcelona, Spain, on May 1, 2014. Tens of thousands of workers marked May Day in European cities with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. (Photo by Manu Fernandez/Associated Press)

Revellers pose during the 24th Street Parade dance music event in Zurich, August 29, 2015. (Photo by Arnd Wiegmann/Reuters)