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 lioness drinks after being fed by senior keeper Glynn Hennessy at ZSL London Zoo on August 10, 2016 in London, England. Today marks World Lion Day which highlights the first global campaign to celebrate the importance and plight of lions worldwide. (Photo by Carl Court/Getty Images)

Four-month-old fox cubs squaring up to each other in Walthamstow, England on August 7, 2015. (Photo by Greg Morgan/Barcroft Media)

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)

Collided passenger train cars are seen in Taebaek, South Korea, Tuesday, July 22, 2014. Two passenger trains collided head-on in eastern South Korea on Tuesday afternoon, killing one passenger and injuring dozens, fire officials said. (Photo by AFP Photo/Yonhap)

Vietnamese female traffic police officers march during a rehearsal for a military parade as part of the 40th anniversary of the fall of Saigon in southern Ho Chi Minh City (formerly Saigon City), Vietnam, on April 26, 2015. Vietnam marks the 40th anniversary of the fall of Saigon on April 30, the event that ended a war that lasted over 30 years, killing up to four million Vietnamese, the Vietnamese government said, and more than 58,000 U.S troops, the U.S. Department of Defense has said. (Photo by Reuters/Kham)

An undated handout picture released on January 10, 2017 by the Issekinicho publishing house shows an inter- species sexual behaviour between a male Japanese macaque and female sika deer, in Yakushima Scientists revealed on January 10, 2017 the “highly unusual” behaviour of a male monkey filmed trying to have sеx with female deer in Japan – a rare case of inter- species nookie. (Photo by Editions Issekinicho/AFP Photo)

Green algae sits on a beach in Kuwait City, Kuwait, 28 February 2017. The formation of green algae is a normal phenomenon that occurs every year at the shores of Kuwait. (Photo by Raed Qutena/EPA)