A man is silhouetted in front of the Allianz-Arena as he walks his dogs at sunrise in Munich, southern Germany, Friday, April 10, 2015. (Photo by Peter Kneffel/AP Photo/DPA)

A visitor holds up her toy bunny to the aquarium glass in front of Aurora the Russian polar bear at the Sao Paulo Aquarium in Sao Paulo, Brazil, Thursday, April 16, 2015. (Photo by Andre Penner/AP Photo)

Women dance during the traditional Feria de Abril (April fair) in the Andalusian capital of Seville, southern Spain, April 21, 2015. The fair will run until April 26. (Photo by Marcelo del Pozo/Reuters)

Lioness and hyena posture to one another, in Masai Mara, Kenya, August 2015. A photographer captured one of the oldest rivalries in the animal kingdom as a pair of lions went head to head with a pack of hungry hyenas. (Photo by Ingo Gerlach/Barcroft Images)

English singer-songwriter, dancer, model and actress Sarah Harding attends the launch of Walkers Bring It Back Campaign at Vinopolis on September 3, 2015 in London, England. (Photo by Joseph Okpako/WireImage)

A police officer sprinkles colored powder onto a police dog at Nepal's Central Police Dog Training School during a dog worship day as part of the Diwali festival, also known as Tihar Festival, in Kathmandu, Nepal, 10 November 2015. The Tihar festival is the second major festival for Nepalese Hindus and this year is held from 10 November 2015. (Photo by Narendra Shrestha/EPA)

Alexo Carmona, 2, looks at Coco, a two-year-old pony, in downtown Havana, in this March 6, 2015 file photo. Nearly a quarter of a million people follow the Reuters Instagram account – and it's still growing fast. To mark the mid-point of 2015, Reuters has compiled the twenty most-liked pictures so far. This picture was 20th most popular. (Photo by Alexandre Meneghini/Reuters)

Demonstrators hold masks depicting Colombian citizen Mile Virginia, who was murdered along with photojournalist Ruben Espinosa and three other women, during a protest in Mexico City, August 16, 2015. Espinosa, a prominent Mexican news photographer was among five people found dead in a middle-class neighborhood of the capital on July 31, 2015. Espinosa, who worked for the weekly magazine Proceso and the photo agency Cuartoscuro, had sought shelter in Mexico City earlier this summer saying he had been followed and threatened in the eastern state of Veracruz. (Photo by Tomas Bravo/Reuters)