A Bengal tiger licks a glass enclosure during a presentation of Bengial tiger cubs at the Malabon Zoo in Malabon City, north of Manila, Philippines, 14 July 2016. The Bengal tiger cubs, which were born at the zoo, are two months old and named “Tiger Duterte” and “Tiger Leni”. The Malabon Zoo has one of the largest private collections of exotic and endemic animals in the Philippines. (Photo by Mark R. Cristino/EPA)

A 10-year-old pet goldfish named George undergoes veterinarian Tristan Rich's scalpel to remove a life-threatening head tumor in this handout picture taken September 11, 2014 and provided to Reuters by the Lort Smith Animal Hospital in Melbourne, Australia. In a 45-minute long procedure described by Rich as “fiddly”, the fish was sedated by water laced with anaesthetic, the tumour removed and the wound sealed with tissue glue followed by antibiotics and painkillers. (Photo by Reuters/Lort Smith Animal Hospital)

Mangli Munda poses on her wedding day with a stray dog in Jharkhand, India on August 30, 2014. An 18-year-old Indian girl has married a stray dog as a part of a tribal ritual designed to ward off an evil spell. Village elders hastily organised the wedding between Mangli Munda and the canine as the teenager is believed to be bringing bad luck to her community in a remote village in Jharkhand state. Mangli's father Sri Amnmunda agreed and even found a stray dog named Sheru as a match for his daughter. And while Mangli was a hesitant bride, she believes that the ceremony will help ensure that her future human husband will have a long life. (Photo by Barcroft Media/ABACAPress)

A person stands in front of a 25.3-meter-long giant rabbit designed by Dutch artist Florentijn Hofman at an old aircraft hangar as part of the Taoyuan Land Art Festival in Taoyuan, northern Taiwan, September 3, 2014. The rabbit is named “Moon rabbit” for the coming Mid-Autumn Festival or the Moon Festival and will be displayed from September 4 to 14 at the Taoyuan military base. (Photo by Pichi Chuang/Reuters)

Hair stylist Marcelo Avatte (R) prepares to fit Isidora Serrano, a 14-year-old who lost her hair due to chemotherapy to treat her bone cancer, with a natural hair wig in the cancer ward of the Luis Calvo Mackenna Hospital in Santiago, October 23, 2014. The wigs, handmade by Italian-Chilean hair stylist Marcelo Avatte and his team, have helped the children regain their self-esteem and confidence during cancer treatment. Renowned for making customised wigs, Avatte has donated more than 300 wigs since 2009 and says he was motivated to begin the project by the pain he felt when his own son lost his hair during chemotherapy. (Photo by Rodrigo Garrido/Reuters)

Afghan artists perform a re-enactment of the lynching of Farkhunda, a 27-year old woman, to protest against her killing in Kabul, April 27, 2015. Farkhunda, who was killed by an angry mob in front of police in the Afghan capital in March for allegedly burning a copy of Islam's holy book was wrongly accused, Afghanistan's top criminal investigator said on March 22. The killing has fuelled anger about the weak rule of law and corruption that is crippling the country's instutitions. (Photo by Omar Sobhani/Reuters)

Tong Jieping, 44-year-old mentally disabled patient, is chained by his foot inside his room, in Qunxing village of Wangjiang county, Anhui province, China, July 14, 2015. Tong was diagnosed mentally ill when he was in his 20s. His parents, both in their 70s, could not afford the medical treatments so they had to lock him up in chains to prevent him from running away, according to Tong's family. (Photo by Reuters/Stringer)

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)