In this Tuesday, June 18, 2013 photo, Zita, a liger – half-lioness, half-tiger – carries her one month-old liliger cub in the Novosibirsk Zoo. The cub's father is a lion, Sam. (Photo by Ilnar Salakhiev/AP Photo)

Pro-government fighters stand next to a tank destroyed during recent fighting in Yemen's southwestern city of Taiz March 14, 2016. (Photo by Anees Mahyoub/Reuters)

A couple takes a photo outside the MUJA (Jurassic Museum of Asturias) in Colunga, northern Spain, November 6, 2015. The scientific team of the Jurassic Museum of Asturias (MUJA) presents their latest studies on the fossil of a Ichthyosaur, which acccording to them is the most complete found in the Iberian Peninsula and one of the few in the world. (Photo by Eloy Alonso/Reuters)

A bus goes through a flooded area in Jiujiang, Jiangxi Province, China, June 19, 2016. A week of torrential rain in southern China has killed dozens of people and forced relocation of tens of thousands of residents, media reported. (Photo by Reuters/China Daily)

Revellers react after falling in the mud at Worthy Farm in Somerset during the Glastonbury Festival, Britain, June 26, 2016. (Photo by Stoyan Nenov/Reuters)

A man prepares tea at a roadside shop on a flooded street in Kolkata, India, August 11, 2016. (Photo by Rupak De Chowdhuri/Reuters)

Revellers, dressed as “Zarramaches”, pose inside the city hall during celebrations to mark Saint Blaise's festivity in Casavieja, Spain February 3, 2017. (Photo by Sergio Perez/Reuters)

In this undated photo made available by journal Nature on January 15, 2014, a northern bald ibis (Geronticus eremita) flies in Tuscany, Italy. A new study released Wednesday, January 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (Photo by Markus Unsöld/AP Photo)