A walruses at Hagenbeck Zoo in Hamburg, Germany on July, 7, 2015. (Photo by Werner Struss/Startraks action)

People take pictures of deer in the Phoenix Park in Dublin, Ireland December 5, 2016. (Photo by Clodagh Kilcoyne/Reuters)

The carcass of a fattened pig, winner of the “holy pig” contest, is attached to a metal frame during a sacrificial ceremony in Sanxia district, in New Taipei City, Taiwan February 1, 2017. The winner of Taiwan's “holy pig” ceremony on Thursday defended the lunar new year tradition against critics who argue the fattened animals are raised under cruel conditions. (Photo by Tyrone Siu/Reuters)

In this picture taken on Sunday, March 5, 2017, a Tehran's urban animal control worker catches a stray dog after being shot with his anesthetic dart on the outskirts of the capital Tehran, Iran. The shelter has been hired by the Tehran city government to take a new, more humane approach to deal with the burgeoning problem of stray dogs in the capital. It’s a sign of changing attitudes among officials in a country where Islamic authorities long saw dogs as “un-Islamic” and would at times confiscate them from people who kept them as pets. (Photo by Vahid Salemi/AP Photo)

From the “Paradise Revisited” story in the November 2013 issue of National Geographic magazine, this image is a beautiful vision of father and son fishermen as they move through the multicolored coral gardens of Kembe Bay, Papua New Guinea, in a traditional outrigger canoe. (Photo by David Doubilet/National Geographic Creative)

An opposition activist clashes with the police during a march against Venezuelan President Nicolas Maduro held on May Day, in Caracas on May 1, 2017. Security forces in riot vans blocked off central Caracas Monday as Venezuela braced for pro- and anti- government May Day protests one month after a wave of deadly political unrest erupted. (Photo by Federico Parra/AFP Photo)

A general view of atmosphere at the annual VOLT Festival in Sopron, 208 kms west of Budapest, Hungary on August 16, 2016. (Photo by Rockstar Photographers)

A gorilla cube named Pepe eats frozen fruit to fight high temperatures at the Bioparc zoo in Valencia, eastern Spain, 28 June 2019. Spanish peninsula is suffering a heat wave with temperatures reaching up to 45 degrees. (Photo by Kai Foersterling/EPA/EFE/Rex Features/Shutterstock)