Mother and Sumatran orangutan calf ( Pongo abelii ) remain together until nine years , longer than any other non-mammal human. During this time, these great apes depend on their parents to learn how to navigate life, looking for what to eat and how to get that food, before becoming independent.
A new study has focused on the role of mothers and shows for the first time that females are actually active teachers
However, unlike us, orangutan mothers did not seem to be actively involved in this learning , but rather behaved like passive role models , whose behaviors were reproduced by their young, according to previous research, based on the acquisition of skills from the point of view of the young.
A new study, published in the journal Scientific Reports , has focused on the role of mothers and demonstrates for the first time that females are actually active teachers.
The team of researchers from the Max Planck Institute for Animal Behavior in Constance (Germany) discovered that when orangutan mothers look for food , they adapt their behavior to age and the capabilities of their young, thus helping them to learn new skills socially.
The work raises the possibility that orangutans carry out teaching –a rare behavior among animals– and sheds light on the factors that led to the evolution of teaching in the humans.
Learning to look for food
During the weaning period that usually occurs at eight or nine years – one of the longest periods of nutritional dependence in any mammal – young orangutans must learn to recognize and process more than 200 foods , many of which require several steps before they can be consumed.
Young orangutans must learn to recognize and process more than 200 foods, many of which require several steps before they can be consumed
For example, the easy-to-eat flowers and leaves do not need any treatment, while the bark must be detached from the tree and scraped with the teeth to extract the nutritive parts. The more difficult products require tools , such as sticks that become brushes to excavate the honey from the hives.
Until now it was thought that the way they learned these complex foraging skills was by observing and watching their mothers do it, and asking for food. But a mystery remained: was this learning process really one-sided?
“It was disconcerting to see mothers always seem so passive during these feeding interactions,” says Caroline Schuppli of the Max Planck Institute for Animal Behavior, leader of the work.
“Mothers spend a lot of time with their young and maintain a very close connection, but they never seemed to actively participate in the acquisition of their abilities,” adds the expert for whom there was a lack of data to fully understand this relationship. In reality, “we did not know the role of the model.”
Active help from mothers
To do this, Schuppli partnered with researchers from the University of Zurich (Switzerland), the Universitas Nasional (Indonesia) and the Max Planck Institute for Evolutionary Anthropology (Germany) to collect data on the role of the mother in children’s skill development. They analyzed data from 1,300 requests for food by 27 young Sumatran orangutans over twelve years in the Suaq Balimbing area of Sumatra, Indonesia.
For each event, it was scored whether the mother allowed the calf to eat the food or not, and this was then analyzed with information on the age of each individual asking for food and the properties of the product itself.
When their offspring request food, mothers adjust their tolerance according to the age of their children (that is, according to their levels of competence) and according to the difficulty of processing the food item
The results showed that orangutan mothers do respond to their young during feeding and thus facilitate learning opportunities : when their young request food, the mothers adjust their tolerance according to the age of your children (that is, based on their proficiency levels) and the difficulty of processing the food item.
Mothers show the highest tolerance levels when their young acquire food recognition and handling skills, as well as when dealing with products that are difficult to process with tools. In the latter case, the parents remain tolerant throughout the period of dependence on their offspring. With leaves that can be picked and eaten whole, they show lower overall tolerance levels and stop sharing when the young have reached a certain age.
“Our results suggest that mothers actively participate in the learning of their offspring’s skills, but they do so in a reactive rather than proactive manner . Interestingly, there were very few instances where food was actively shared. This means that the younger orangutans have to take the initiative during the learning process, ”emphasizes Schuppli.
According to the authors, it remains to be seen whether or not maternal behavioral adjustments can be classified as functional teaching . “These findings give us a special insight into the factors that lead to the evolution of teaching,” says the scientist. “Although this is quite rare in the animal kingdom, the work shows that these orangutans have at least some cognitive, ecological and social conditions to support teaching ability,” he concludes.
Mulati Mikeliban et al. “Orangutan mothers adjust their behavior during food solicitations in a way that likely facilitates feeding skill acquisition in their offspring” Scientific Reports
Rights: Creative Commons.