We already knew that orangutan babies stay with their mothers for a long time. Now research shows that they also nurse for a significant part of that time.
Orangutans are the mammals that breastfeed the longest. Now scientists have an idea of how long: a full 6.5 years.
The study, which was published in Communications Biology at the end of May, describes how researchers determined this by using a method that identifies specific proteins in orangutan faeces, according to phys.org. Orangutan milk contains several proteins that cannot be found elsewhere. Therefore, the presence of these proteins in the faeces is a very clear indicator that the baby is still nursing.
The research team collected stool samples from specific orangutans on Borneo, in the Danum Valley Conservation Area in Malaysia, over a period of 2 years and 7 months. Of the 20 samples that came from orangutans that were under 6.5 years old, these specific milk proteins could be found in all of them. Therefore, the study indicates that orangutan mothers breastfeed their babies for at least 6.5 years.
The study also suggests that the more milk the baby consumes, the stronger its biological defence gets and the higher the prevalence of probiotic gut bacteria.
Although the milk from the orangutan mother is good for the baby, the finding once again emphasises how dependent orangutan babies are on their mothers. In the wild, the babies stay with their mothers until they are about 8 years old – longer than most other animals. The downside of this slow reproduction is that it means that orangutan populations recover very slowly when, for example, deforestation, hunting and forest fires threaten their existence.
You can adopt an orangutan baby who has lost its mother here.