Yuchen Chao of Chinese Taipei in action during the Beach Handball Women's Tournament match between Chinese Taipei and Paraguay at The Beach Handball Arena, Tecnopolis Park, Buenos Aires, Argentina, October 12, 2018. (Photo by Lukas Schulze for OIS/IOC/Handout via Reuters)

In this Thursday, October 18, 2018 photo, contestants wait for their performance backstage during the National Amateur Body Builders' Association competition in Tel Aviv, Israel. Dozens of glistening competitors took the stage for the annual body building and fitness competition last week. But behind the scenes, machismo makes way for cooperation. (Photo by Oded Balilty/AP Photo)

Behaviour winner; Courting Royals: two royal terns in courtship display by Kristian Bell. Another beautiful morning on a beautiful beach on the Gulf Coast of Florida seemed to prompt these two royal terns to commence an intricate courtship dance. The photograph was taken with a Canon 300mm lens and 2x extender. (Photo by Kristian Bell/Deakin University/Royal Society Publishing Photography Competition 2018)

A leaf from a sweetgum tree (Liquidambar styraciflua) lies on the grass at Godewaersvelde early October 27, 2017. (Photo by Philippe Huguen/AFP Photo)

David Goffin of Belgium meets a koala during a promotional event for the Australian Open tennis tournament at Melbourne Park on January 17, 2018. (Photo by Fiona Hamilton/Reuters/Tennis Australia)

A photographer tested the concentration of several pairs of dogs as he captured their reactions to treat time in a series of shots. Christian Vieler, 47, of Waltrop, Germany, has been a professional dog photographer since 2016. He came up with the idea of snapping two dogs catching treats simultaneously. Here: Basset Hounds. (Photo by Vieler Photography/Caters News Agency)

A Southwest Airlines jet takes off from Reagan National Airport with a thunderhead to the east on June 20, 2017 in Alexandria, VA. (Photo by Jonathan Newton/The Washington Post)

In this handout photograph received from Sumukha J.N on December 15, 2016, the newly-discovered spider Eriovixia Gryffindori sits on a leaf in the Kans in India's Western Ghats. (Photo by Sumukha J.N./AFP Photo)