Undated David Yarrow handout photo of a gorilla as the self-taught wildlife photographer promotes his book, Encounter. (Photo by David Yarrow/Clearview/PA Wire)

A large bull walrus returns to the shores of Prins Karl Forland after diving and feeding on clams. (Photo by Paul Nicklen/National Geographic). Svalbard, Norway, 2011

A photographer could bear-ly believe his eyes when a bear started waving at him. The friendly animal wandered to the front of his enclosure before sitting back in full view of zoo guests. He then lifts his powerful paw and excitedly waves in an almost human-like way at his new audience. The hilarious encounter was captured by keen photographer Andrey Slepnev, 31, while on a trip to Madrid Zoo, Spain on March 24, 2016. (Photo by Andrey Slepnev/Caters News)

“After an afternoon of hiking and exploring the caves of Rhossili Bay, West Glamorgan, we caught the sun breaking through the clouds”. (Photo by Megan Warren-Davis/The Guardian)

An Indian Sikh Nihang, or warrior, performs Gatka martial arts skills during a procession at the Golden Temple in Amritsar on January 6, 2014, as part of birth anniversary celebrations of Guru Gobind Singh. The birth anniversary of Guru Gobind Singh, the tenth Sikh guru, is marked on January 6. (Photo by Narinder Nanu/AFP Photo)

A woman is tattooed by an artist during Warsaw Tattoo Convention 2014 in Warsaw November 29, 2014. (Photo by Kacper Pempel/Reuters)

A girl calls to her mom as she stands near a dead whale on the shore Monday morning, April 25, 2016, on the cobblestone beach at Lower Trestles on San Onofre State Beach, just south of San Clemente, Calif. (Photo by Jeff Gritchen/The Orange County Register via AP Photo)

A flock of sheep huddles together while snow spindrift is whipped up by strong winds in Swaledale, North Yorkshire, UK on March 17, 2017. (Photo by Paul Kingston/NNP North News & Pictures Ltd)