Arctic wolves in their new enclosure in the wildlife park in Hanau, Germany, 10 February 2015. The pack is one of the park's main attractions, which specializes in local and European breeds. (Photo by Boris Roessler/EPA)

In this January 7, 2016, photo, conservationists of Borneo Orangutan Survival Foundation hold a baby orangutan rescued along with its mother during a rescue and release operation for orangutans trapped in a swath of jungle in Sungai Mangkutub, Central Kalimantan, Indonesia. Last year's forest fires drove orangutans closer to the river bank, where they had to live in an over-populated swath of forest as thin as 30 meters wide along the river. (Photo by Dita Alangkara/AP Photo)

Revellers take part in an annual block party known as “Cordao de Prata Preta”, one of the many carnival parties to take place in the neighbourhoods of Rio de Janeiro, February 6, 2016. (Photo by Pilar Olivares/Reuters)

A man rides a motorcycle along a street in the snow in Altay, Xinjiang Uighur Autonomous region, February 9, 2016. (Photo by Reuters/Stringer)

Girls dressed up in traditional Egyptian clothes from the early 20th century pose for a picture before they get their photos taken on the historical Al-Moez street of Islamic Cairo, Egypt, January 17, 2016. (Photo by Asmaa Waguih/Reuters)

Mechanic and welder Sergei Kulagin, 32, strengthens the bracing of a spider sculpture, made by Kulagin, during a demonstration on the wall of an automobile repair workshop in the town of Divnogorsk outside Krasnoyarsk, Siberia, October 15, 2014. Enthusiast Kulagin, who works as a mechanic of an automobile service station, created about 20 sculptures made of used car parts and components during his non-working hours. (Photo by Ilya Naymushin/Reuters)

A South Sudanese People Liberation Army (SPLA) soldier patrols the streets in Malakal on January 21, 2014. (Photo by Harrison Ngethi/AFP Photo)

Tourists take a “selfie” as demonstrators burn a trash container during a May Day rally in Barcelona, Spain, on May 1, 2014. Tens of thousands of workers marked May Day in European cities with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. (Photo by Manu Fernandez/Associated Press)