For the first time, researchers have documented a heartwarming case of a young female orangutan adopting her younger sister after they both lost their mother.
The consequences of losing a mother at an early age can be catastrophic for a small animal. This is particularly true of orangutans, who, apart from humans, depend on their mothers for the longest period of time.
However, there is hope for an abandoned orangutan baby if it is adopted. This is the practice at our local partner organisation BOS Foundation’s rehabilitation centre, when local authorities hand over orphaned orangutans. Now, however, we are also seeing that adoption can take place in the wild. Recently, a case where an orangutan took care of her little sister after she lost her mum was described in detail for the first time in research, as reported by National Geographic.
Sisters reunited
At first, researchers thought that the two orangutans, Rossa and Ronnie, who live in Gunung Palung National Park, were mother and daughter. However, something didn’t seem quite right: Rossa looked far too young to be the mother of a six-year-old.
DNA analysis revealed that Rossa and Ronnie were actually sisters. Their mother, Veli, had died, and Rossa had adopted Ronnie and taken care of her.
Although Rossa had “moved away from home” when Veli disappeared from her in 2016, the two sisters were reunited, with Rossa treating Ronnie as her own child. Another sign of deviation was that the two kept a little more distance from each other during the day than a typical mother-child pair would. However, they were just as willing to share food as a mother and child normally would. Without her sister, Ronnie would probably not have survived.
A first amongst orangutans
Rossa had her own baby in 2019 and now cares for her infant while also continuing to look after Ronnie. At the same time, Ronnie is showing signs of growing independence, such as building her own nest at night. It is completely normal for an older orangutan to gradually make space for younger ones. Although Ronnie still stays close to her older sister and adoptive mother, she has clearly developed more quickly than many other orangutan youngsters. After her mother passed away in 2020, Ronnie began transitioning into her own adult life.
This is not the first time that adoptions have been seen among great apes, but it is the first documentation of the phenomenon among orangutans. It shows that orangutans have complex social lives, even though they are predominantly solitary animals.
Read also: Young orangutan found alone on plantation
The photo above is from Nyaru Menteng, and does not depict the mentioned orangutans. Photo credit: BPI