This huge male orangutan is having a right old laugh as he squints his eyes and shows his huge teeth. The orangutan, called Bimbo, was relaxing on a platform around 5m high in his enclosure when he broke out into a laugh. But his happy smile soon disappeared when another orangutan came over to see what was going on. Bimbo – the only male in the group of five apes at Leipzig Zoo, in Germany - appears to be laughing in much the same way as a human would. (Photo by Martina Radtke/Solent News)

Residents watch volcanic smoking and ashes rising from Mount Sinabung during an eruption in Karo, North Sumatra, Indonesia, February 24, 2016. Authorities have repeatedly called on local residents to remain patient in dealing with the impact of Sinabung's eruptions, which some experts have predicted will continue for five more years. (Photo by Xinhua/Barcroft Media)

A giant river otter, the world's largest otter species, looks out of its enclosure at the newly completed River Safari in Singapore, on March 25, 2013. (Photo by Wong Maye-E/Associated Press)

A guard stands at Dityatki checkpoint, marking a 30 km (18-mile) zone around the Chernobyl nuclear power plant April 23, 2013. Ukraine will mark the 27th anniversary of the Chernobyl disaster, the world's worst civil nuclear accident, on April 26. (Photo by Gleb Garanich/Reuters)

A Brazil fan enjoys the atmosphere prior to the 2014 FIFA World Cup Brazil Semi Final match between Brazil and Germany at Estadio Mineirao in Belo Horizonte, Brazil, on Jule 8, 2014. (Photo by Robert Cianflone/Getty Images)

A giant panda named Kai Kai looks on as he opens a gift to celebrate his upcoming 14th birthday at the River Safari wildlife park in Singapore on September 10, 2021. (Photo by Roslan Rahman/AFP Photo)

Two young boys kneel on stools on either side of a round table as one uses a match to this the other's cigarette, November 12, 1928. (Photo by FPG/Getty Images)

Former Soviet President Mikhail Gorbachev and his daughter Irina Virganskaya attend the Free Your Mind Award Presentation at the Cinema For Peace charity dinner at the China Club on November 8, 2009 in Berlin, Germany. (Photo by Sean Gallup/Getty Images). BERLIN – NOVEMBER 08 2009