These heartbreaking photos show young orangutans being cared for at the Sumatran Orangutan Conservation Programme (SOCP) in Indonesia. SOCP rehabilitates orphaned, captive and injured orangutans, aiming to release them back into the wild. Since being established in 1999, more than 220 orangutans have been returned to the forest.

orangutans Indonesia deforestation
A young Sumatran orangutan sits in a cage at the Sumatran Orangutan Conservation Programme's rehabilitation centre in Kuta Mbelin, north Sumatra, IndonesiaUlet Ifansasti/Getty Images

The organisation regularly confiscates baby orangutans, destined for the illegal pet trade, from wildlife traffickers. These suppliers buy the orphaned apes from poachers who shoot their mothers and capture the helpless babies.

Orangutans have the longest childhood of any animal (apart from humans), often staying with their mothers until they are six or seven years old. They are completely dependent on their mothers for the first two years of their lives, and are only weaned at about five years old.

orangutans Indonesia deforestation
A worker carries baby Sumatran orangutans at the Sumatran Orangutan Conservation Programme's rehabilitation centreUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
Dina, a young Sumatran orangutan rescued from illegal trade and suffering from cerebral malaria, sleeps at the clinic facility at the Sumatran Orangutan Conservation Programme's rehabilitation centreUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A young orangutan is seen inside a cage at the Sumatran Orangutan Conservation Programme's rehabilitation centre in Kuta MbelinUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
Young Sumatran orangutans play in a cage at the Sumatran Orangutan Conservation Programme's rehabilitation centreUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
Sumatran orangutans are seen inside a cage at the Sumatran Orangutan Conservation Programme's rehabilitation centreUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
Sumatran orangutans are seen inside a cage at the Sumatran Orangutan Conservation Programme's rehabilitation centreUlet Ifansasti/Getty Images

Before they can be released into the wild, the orangutans at SOCP have to learn how to survive in the forest – a process which takes months or even years. They are transferred to a forest reserve where they develop the skills their mothers would have taught them – which plants are edible, how to recognise less obvious foods such as termite nests, etc. They also learn how to build nests in the trees, out of the reach of ground-dwelling predators and soil-living parasites.

To help them, SOCP staff look for particular foods and eat (or pretend to eat) them just as the orangutan's mother would have done. As they develop, they are allowed to explore the forest before returning to cages at night to sleep.

orangutans Indonesia deforestation
Young Sumatran orangutans play in the trees as they train for life in the forestUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A young Sumatran orangutan plays at the centreUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A worker carries Sumatran orangutans to acclimatise them to living in the forestUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A Sumatran orangutan plays inside a cage at the Sumatran Orangutan Conservation Programme's rehabilitation centreUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A young Sumatran orangutan eats at the Sumatran Orangutan Conservation Programme's rehabilitation centreUlet Ifansasti/Getty Images

When an orangutan is ready, it may be released into the reserve or in an area deeper in the forest. After their release, they are tracked and monitored to evaluate each ape's health, survival skills and overall progress.

orangutans Indonesia deforestation
A worker carries a Sumatran orangutan before releasing them into the wildUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A worker puts a Sumatran orangutan into a box to prepare it for being released into the wildUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A Sumatran orangutan looks out from a box as it is prepared to be released into the wildUlet Ifansasti/Getty Images

There are thought to be around 14,000 Sumatran orangutans left in the wild. The critically endangered species, which lives exclusively in the north of the Indonesian island Sumatra, is being pushed to extinction by habitat loss and poaching.

Thousands of square miles of forest and peatland have been cleared to make way for palm-oil plantations, threatening the last remaining and viable habitat for the Sumatran orangutan, as well as populations of rhino, tiger and elephant. Land is cleared using slash-and-burn forest fires that rage out of control across Indonesia. The World Wildlife Fund estimated that six-month long forest fires in Kalimantan in 1997 left up to 8,000 orangutans dead.

orangutans Indonesia deforestation
Forested land is cleared to make way for a palm-oil plantation in the Singkil peatlandUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
Trees are cut down to make way for another palm-oil plantation in the Singkil peatland in Aceh province, Indonesia – a natural habitat for the Sumatran orangutanUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A palm-oil plantation in Trumon sub-district, South Aceh, Aceh province, IndonesiaUlet Ifansasti/Getty Images

SOCP aims to reduce the conflicts between humans and apes at the edge of the forest. Orangutans are increasingly injured or killed for raiding the fruit crops of local farmers. The centre educates the local population in an effort to change perceptions about animal welfare, as well as to reach an understanding of sustainable development, and natural resource management.

These photos show SOCP staff performing surgery on an adult-male orangutan named Tengku who was rescued from a farm and discovered to have more than 60 air-rifle pellets embedded in his body.

orangutans Indonesia deforestation
A veterinarian shows an X-ray photo of Tengku, a Sumatran orangutan rescued from a farm and found to have more than 60 air-rifle pellets in his bodyUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
Veterinarians at the Sumatran Orangutan Conservation Programme perform surgery on an injured orangutanUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
A staff member at the Sumatran Orangutan Conservation Programme puts nail polish on an ape to distract him after surgeryUlet Ifansasti/Getty Images
orangutans Indonesia deforestation
Nail polish is seen on a Sumatran orangutan undergoing surgeryUlet Ifansasti/Getty Images

This week (13 to 19 November) has been designated as Orangutan Caring Week. Find out what you can do to help protect these critically endangered animals.