A man holds a pigeon during the British Homing World show of the year at Blackpool's Winter Gardens in Blackpool, north west England on January 17, 2016. Homing pigeon fanciers from across Europe gathered to find the Supreme Show Champion with judges casting their eyes over hundreds of birds on show. The Royal Pigeon Racing Association organises the event and has Queen Elizabeth II, who keeps pigeons at Sandringham, as its patron. (Photo by Andrew Yates/Reuters)

A polar bear cub snuggles up against her mother Valeska, in their enclosure at Bremerhaven's (Bremen's) Zoo by the Sea, Germany March 9, 2016. The female cub, who is yet to ne named, was born on December 11 last year. (Photo by Carmen Jaspersen/Reuters)

Enjoying a tickle from her keeper, an orphaned orangutan at the SOCP Quarantine Centre in Sumatra, Indonesia on March 20, 2016. The island’s orangutan population has been devastated in recent years as the forest areas are destroyed to make way for palm oil plantations. (Photo by Jami Tarris/Barcroft Media)

Female sea lion “Sarasa” holds a hose with her mouse to help a trainer clean her room at the Shinagawa Aqua Stadium aquarium in Tokyo on December 30, 2014. The aquarium is carrying out year-end general cleaning of their facilities. (Photo by Yoshikazu Tsuno/AFP Photo)

People pose for souvenir photos along peach blossom flowers at a field in Hanoi February 6, 2015. The peach blossom, believed to bring luck to families, is used to decorate homes during the Vietnamese “Tet” (Lunar New Year festival), which will take place from February 14 to February 24. (Photo by Reuters/Kham)

Henry Leese drives a 1952 British Rail Ivatt number 46512 at Strathspey Steam Railway on August 27, 2013 in Aviemore,Scotland. This year marks the 150th anniversary of the Highland Main Line built as a transportation link to the South for lairds and landowners living in northern Scotland. (Photo by Jeff J. Mitchell)

Norma Galicia aka “Pirulina” takes part in a demonstration during the commemoration of the International Day for the Elimination of Violence Against Women, in Guatemala City on November 25, 2013. So far this year, 696 women have died due to violent events in Guatemala. (Photo by Johan Ordonez/AFP Photo)

This combination of April 15, 2013 and April 2, 2014 photos show a police officer clearing Boylston Street following a bomb blast near the finish line of the 2013 Boston Marathon, and pedestrians crossing at the same corner nearly a year later in Boston. (Photo by Charles Krupa/AP Photo)