The Tapanuli orangutan was discovered as a new species of orangutan in late 2017 after DNA analysis, bringing the total species of orangutans up to 3 including the Borneo and Sumatra orangutans. They are restricted to living in South Tapanuli in the island of Sumatra in Indonesia and although only discovered recently they are thought to be the most ancient of the three orangutan species. At 15 years of age, females will have their first offspring, only giving birth every 5 to 7 years which means that reproduction rate is very low. Babies weigh about 1.3kg at birth and twins are extremely rare. Infants remain dependant for a long time, not leaving their nest until they reach maturity. Males will start to wonder off when they reach 15 years of age and the females mature at 11 but stay a few years longer to learn how to be a mother. They prefer a solitary life to large groups but a male may stay with the mother of their offspring, although this is rare and they usually move on after the mating season. They have long limbs that allow them to travel through the trees with ease but this affects their movement on the ground. Their days usually start at sunset where they will start their quest to find food. Males will usually travel alone and females will travel with their baby or adolescent. After they feed for a few hours they will  start again until late afternoon before they make a nest in a tree for the night. They are the most endangered of the 3 species with only 800 of their kind left and the numbers are decreasing due to the threats they face.