A young oriental small-clawed otter at the zoo in Neumuenster, Germany, March 5, 2014. The six young otters (one male, five female) were born on December 7, 2013. (Photo by Maja Hitij/EPA)

Female bodybuilders prepare to compete in the “Miss Bikini” category of the NABA/WFF Asia-Seoul Open Championship in Seoul on April 17, 2016. (Photo by Ed Jones/AFP Photo)

A female bodybuilder apples oil to another performer backstage before an amateur competition in the Israeli city of Dimona, in this April 3, 2014 file photo. (Photo by Finbarr O'Reilly/Reuters)

Female soldiers with their faces painted in the colours of the Venezuelan flag, march during a military parade to celebrate the anniversary of Venezuela's independence in Caracas, July 5, 2015. (Photo by Jorge Dan Lopez/Reuters)

A newly born female White Rhino runs alongside her mother in Ramat Gan Safari Park near Tel Aviv, Israel, on September 3, 2014. She was born three weeks ago, after more than twenty years without a female White Rhino birth in the Safari, Sagit Horowitz, the safari spokeswoman said. (Photo by Ariel Schalit/AP Photo)

An elephant bull charges a female hippopotamus as her calf scampers to safety, in Erindi Private Game Reserve in Windhoek, Namibia. (Photo by Rian van Schalkwyk/Barcroft Media)

A Syrian Democratic Forces (SDF) female fighter adjusts a mortar in northern Deir al-Zor province ahead of an offensive against Islamic State militants, Syria February 21, 2017. (Photo by Rodi Said/Reuters)

A female goalkeeper saves the ball at the Mathare Environmental Conservation Youth Center during a soccer match to celebrate the International Women's day in Nairobi, Kenya, March 8, 2017. (Photo by Thomas Mukoya/Reuters)