Leo, an orphaned Sumatran orangutan, is taken to the Sumatran Orangutan Conservation Programme rehabilitation centre. Leo will join other orangutans who have been reintroduced to the Pinus Jantho nature reserve. The SOCP has gradually formed a completely new wild population of species that have been threatened with extinction. (Photo by Sutanta Aditya/Barcroft Images)

An orphaned rhesus monkey and white dove that seemed to have lost its mate forged a special bond at the Neilingding Island-Futian National Nature Reserve in China. The monkey was born on the island but had strayed from its mother. Luckily, it was taken in by work staff in the protection center and became friends with the pigeon that had lingered there after possibly losing its mate. (Photo by CNImaging/Photoshot)

Meet the star students of orangutan school – the unique rehab centre where orphaned apes are taught how to climb trees and survive in the wild without their mum and dad. (Photo by Caters News)

A US Marine feeds an orphan kitten found after a heavy mortar barrage near “Bunker Hill” during the Korean War. (Photo by Sgt Martin Riley/Getty Images). 1953

This is Raymond, an orphaned koala that was found abandoned beside a road in Brisbane, Australia. He was named after the man who found him.

The stories of a unique bond between a child and their pet are as timeless as they come, but rarely does the pet have wings. Such is the case with photographer Cameron Bloom whose son Noah happened upon a baby magpie in 2013 when the family was out walking near their home in Newport, Australia. After consulting with a veterinarian, the family learned to raise the orphaned bird, who they affectionately named Penguin.

Photo taken on September 19, 2015 shows a baby Brazilian opossum at the “Parque Estoril” zoo in Sao Bernardo do Campo of Sao Paulo, Brazil. According to local press, the “Parque Estoril” zoo houses currently 23 orphan cubs of wild animals rescued in the south region of Sao Paulo, victims of illegal wildlife trade or problems caused by urban growth. According to the zoo, all the animals arrived in the last three months, and many of them, not being able to be reintroduced to their natural habitat, will be used as examples in environmental education classes. (Photo by Rahel Patrasso/Xinhua via ZUMA Wire)

Mary, 8-months-old female orphan elephant, drinks milk at Winga Baw Elephant Conservation Camp during the ceremony to mark World Elephant Day at Bago Region, Myanmar, 12 August 2017. Winga Baw Elephant Conservation Camp, 34-hectare former timber camp for logs located in Bago Region, currently has 14 elephants and was opened for recreation for locals as well as for tourists. World Elephant Day is marked annually on 12 August. (Photo by Lynn Bo Bo/EPA/EFE)