Orangutans live in the wild only in Sumatra and Borneo, Indonesia. They are the largest tree-dwelling mammal in the world. They share 97% of their DNA in common with humans. In 2016, the Bornean orangutan was declared critically endangered. Habitat destruction and hunting are the main threats to its survival. The orangutans in these photographs are orphans whose mothers were killed. As babies they were handed over to Borneo Orangutan Survival (BOS) Foundation who work to rehabilitate orphaned orangutans and re-introduce them to their natural habitat.