A new study led by the Max Planck Institute of Animal Behavior in Konstanz, Germany has analyzed the interaction between orangutan mothers and their infants in Sumatra, Indonesia. The researchers found that when orangutan mothers are foraging, they tailor their behavior to match the age and capacities of their offspring, thereby helping them to learn.
According to the researchers, this study uncovered the first evidence yet of active involvement by orangutan mothers in their offspring’s learning of new skills.
“Immature orangutans acquire their feeding skills over several years, via social and independent learning,” wrote the study authors. “So far, it has remained uninvestigated to what extent orangutan mothers are actively involved in this learning process. We conclude that orangutan mothers have a more active role in the skill acquisition of their offspring than previously thought.”
During their infancy, orangutans must learn to recognize and process over 200 food items, many of which require several steps before they can be eaten. For instance, while most flowers and leaves require no previous processing, bark must be loosened from the trees and scraped with the teeth in order to access its nutritive parts. The most difficult foods, such as honey from bee hives, require even the use of tools such as sticks in order to consume it.
According to the researchers, immature orangutans learn such complex skills by observing their mothers while they are eating.
“It was puzzling that mothers always seemed so passive during these feeding interactions,” said study lead author Dr. Caroline Schuppli, an evolutionary biologist at the Max Plank Institute. “Mothers have so much time with their offspring, and maintain such a close connection, but they never appeared to be actively involved in the skill acquisition of their young.”
However, by analyzing over 1,300 instances of immature orangutan’s food solicitation – asking or trying to obtain food from their mother – Dr. Schuppli and her colleagues have found that orangutan mothers do in fact respond to their offspring during feeding, and therefore facilitate learning opportunities.
When their offspring solicit food, mothers usually adjust their “tolerance” according to their offspring’s age and how difficult the food item is to process.
“Our findings suggest that orangutan mothers are actively involved in their offspring’s skill learning,” Dr Schuppli said. “However, they do this in a reactive, rather than proactive way. Interestingly, there were very few incidents of active food sharing only. This means that orangutan immatures need to take the initiative during learning. This is very different from humans, where active teaching plays an important role and role models are much more proactive.”
The study is published in the journal Nature Scientific Reports.
By Andrei Ionescu, Earth.com Staff Writer