Smithsonian National Zoo biologist Leigh Pitsko releases a male lion cub for its swim test in the zoo habitat moat, in Washington May 6, 2014. Four, unnamed ten-week old lion cubs were tested today for their ability to swim and remove themselves from their zoo habitat moat. (Photo by Gary Cameron/Reuters)

Emma White, of Team Cyclocrossworld, hits the dirt hard during the USA Cycling Cyclo-cross National Championship Elite Women's race at the Valmont Bike Park in Boulder, Colorado, on January 12, 2014. (Photo by Jeremy Papasso/The Daily Camera)

Ramoncito Campo kisses his wife Hernelie Ruazol Campo on a flooded street during a southwest monsoon that battered Manila August 8, 2012. The newly-wed couple pushed through with their scheduled wedding despite severe flooding that inundated wide areas of the capital and nearby nine provinces. (Photo by Reuters/Courtesy of Ramoncito Campo)

Models pose for a group photograph outside the Victoria's Secret shop on New Bond Street in central London, December 1, 2014. The 2014 Victoria's Secret Fashion Show will be held in London on Tuesday. (Photo by Andrew Winning/Reuters)

Model Adriana Lima attends the 2011 Victoria's Secret Fashion Show After Party at Dream Downtown on November 9, 2011 in New York City. (Photo by Andy Kropa/Getty Images)

The First U.S. Spacewalk – Gemini 4 Ed White made the United States' first spacewalk on June 3, 1965 during the Gemini 4 mission. The extra-vehicular activity (EVA) started at 19:45 UT (3:45 p.m. EDT) on the third orbit when White opened his hatch and used the hand-held manuevering oxygen-jet gun to push himself out of the capsule. (Photo by NASA)

One-day-old baby giraffe calf Gus looks at the camera at Noah's Ark farm on May 12, 2017 in Bristol, England. The baby giraffe was born yesterday at the zoo farm in North Somerset. In the wild, populations of giraffes are suffering from a continuing decline, with 97,500 estimated in Africa in 2015. Since 1985 the total giraffe population has fallen by 35%. New arrival Gus joins brothers George, 4 and Geoffrey, 2. (Photo by Matt Cardy/Getty Images)

In this Sunday, February 18, 2018 photo, Palestinian camel herder Salem Rashaideh, leads the way for the camels in the territory of Israeli Kibbutz Kalya, near the Dead Sea in the West Bank. For three months a year, in the winter time Bedouin Arab herders take their 130 camels to graze on the shores of the Dead Sea, at the lowest place on Earth. (Phoro by Oded Balilty/AP Photo)