Dema and Manis, the 26-day-old endangered Sumatran Tiger cubs play together at the “Taman Safari Indonesia” Animal Hospital, on February 26, 2007 in Cisarua, Bogor Regency, West Java, Indonesia. The two Sumatran tiger-cubs recently born at the hospital have been rejected by their mother Cicis, while baby Orangutans, Irma and Nia have also been rejected by their mothers. All babies are being looked after by staff at the Animal Hospital. (Photo by: Dimas Ardian/Getty Images)

In this photo taken on Wednesday, February 17, 2016, a volunteer fighter with the Syrian Government forces sits atop a tank in the province of Raqqa, Syria. In recent weeks, Syrian government forces captured dozens of villages and towns across the country. (Photo by Alexander Kots/Komsomolskaya Pravda via AP Photo)

Muhannad al-Kadiri (R),18, and Ibrahim Eid, 16, demonstrate their Parkour skills over a military vehicle in the rebel-held city of Inkhil, west of Deraa, Syria, February 4, 2017. (Photo by Alaa Al-Faqir/Reuters)

A street vendor warms his foot around a fire during cold weather in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria, January 4, 2016. (Photo by Khalil Ashawi/Reuters)

A Syrian refugee girl plays outside a tent at a refugee camp in Zahle in the Bekaa valley November 18, 2014. In October, Lebanon, which has the highest per capita concentration of refugees in the world at one in four residents, said it could not cope with more than one million Syrians and has asked for funds to help look after them. (Photo by Mohamed Azakir/Reuters)

Syrian refugees covered with dust arrive at the Trabeel border, after crossing into Jordanian territory with their families, near the northeastern Jordanian border with Syria, and Iraq, near the town of Ruwaished, east of Amman September 10, 2015. (Photo by Muhammad Hamed/Reuters)

Internally displaced Syrian children play inside a refugee camp in the Hama countryside, Syria January 1, 2016. (Photo by Ammar Abdullah/Reuters)

Orphaned baby rhinos seen on August 28, 2014 in Lewa Wildlife Conservancy, Ngare Ndare Forest, Kenya. Lewa Wildlife Conservancy in Kenya is hand-raising three orphaned baby rhinos; Nicky, Hope and Kilifi. Baby rhino Hope was rescued by rangers when the poachers killed his mother – now he is been taken care off 24 hours-a-day at Lewa Wildlife Conservancy. The wildlife reserve hit the headlines when Prince William proposed to Kate Middleton there in 2010. Rhinos around the world are becoming extinct as a result of the brutal poaching fuelled by an illegal international market for their horns. (Photo by Luca Ghidoni/Barcroft Media)