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Migrant orangutans watch the locals to learn what to eat and other local customs

In the world of non-human animals, orangutans share a unique and prolonged bond with their mothers. They spend years together before the young leave their mothers, and are then considered migrant orangutans.

The younglings nurse for at least six years. This is followed by another three years of life training, such as learning what foods are best to eat. During this time, they learn the art of foraging, the art of choosing and processing an incredibly diverse range of foods from their mother.

The mystery that puzzled scientists was how these orangutans, once they ventured away from their mothers into different territories with vastly different foods, knew what to eat and how to eat it.

Thanks to a multinational group of researchers, we now have a clearer answer to this question.

The golden rule followed by these migrant orangutans, it seems, is ‘observe and do as the locals do.’ These findings were recently published in the scientific journal, Frontiers in Ecology and Evolution.

How the research team studied migrant orangutans

Julia Mörchen is a doctoral student at the Max Planck Institute for Evolutionary Anthropology and the University of Leipzig in Germany, and the study’s lead author.

She stated, “Here we show evidence that migrant orangutan males use observational social learning to learn new ecological knowledge from local individuals after dispersing to a new area.”

 She added, “Our results suggest that migrant orangutan males not only learn where to find food and what to feed on from locals, but also continue to learn how to process these new foods.”

How do migrant orangutans acquire this new knowledge?

The answer lies in a behavior termed ‘peering.’ This action involves intensely observing for at least five seconds from within two meters of a role model. When peering, the observing orangutan mimics the role model’s actions with head movements, indicating keen interest.

This learning process is critical for the male orangutans, who tend to migrate to new areas after becoming independent. Females, on the other hand, usually stay close to their birth homes.

Mörchen added, “What we don’t yet know is how far orangutan males disperse, or where they disperse to. But it’s possible to make informed guesses: genetic data and observations of orangutans crossing physical barriers such as rivers and mountains suggest long-distance dispersal, likely over tens of kilometers.”

The research team analyzed 30 years of observations collected by 157 trained observers. They examined 77 migrant adult male Sumatran orangutans at the Suaq Balimbing research station in Southwest Aceh, and 75 adult migrant male Bornean orangutans at the Tuanan station in Central Kalimantan.

Observing the peering behavior of migrant orangutans

The focus of their study was peering behavior during 4,009 instances when these males were within 50 meters of a neighbor, be they adult females, juveniles, or other males. They observed peering behavior by males 534 times, occurring in 5.2% of these associations.

In Suaq Balimbing, males peered most frequently at local females and juveniles, and least at adult males. This trend was reversed in Tuanan, where males primarily peered at other males and juveniles, and rarely at adult females.

The observed males interacted more frequently with the food they had peered at, indicating that they were putting their newly learned skills into practice.

Research team very happy with their results

“Our detailed analyses further showed that the migrant orangutan males in our study peered most frequently at food items that are difficult to process, or which are only rarely eaten by the locals,” said Dr. Anja Widdig, a professor at the University of Leipzig and co-senior author of the study.

Dr. Caroline Schuppli, a group leader at the Max Planck Institute of Animal Behavior in Konstanz and co-senior author, added, “Interestingly, the peering rates of migrant males decreased after a couple of months in the new area, which implies that this is how long it takes them to learn about new foods.”

However, the researchers cautioned that it is still unknown how many times an adult orangutan needs to peer at a particular behavior to master it.

Depending on the complexity or novelty of the learned skill, adults may continue to experiment with certain food items they first learned about through peering. This continued exploration may help them better understand, strengthen, and memorize new information, or compare it with prior knowledge.

More about orangutans

Orangutans, native to the rainforests of Borneo and Sumatra, are majestic creatures. They’re our closest relatives, sharing nearly 97% of their DNA with humans.

But today, these gentle giants are on the brink of extinction. They’re under threat due to human activities such as deforestation, illegal hunting, and the wildlife trade.


There are three recognized species of orangutans: Bornean, Sumatran, and Tapanuli. All three face significant challenges.

The International Union for Conservation of Nature (IUCN) classifies Bornean orangutans as “Critically Endangered.” Sumatran orangutans as “Critically Endangered.” Tapanuli orangutans, with a population of fewer than 800, are listed as “Critically Endangered.”

Endangered status

Deforestation is the main threat to orangutan survival. Vast expanses of their forest habitats are disappearing to make way for palm oil plantations.

Palm oil, used in countless products from shampoo to chocolate, drives a multi-billion-dollar industry. This industry is responsible for the destruction of over 80% of orangutan habitat in the last 20 years.

Illegal hunting also poses a serious threat. Despite protective laws, hunters kill orangutans for meat, capture babies for the illegal pet trade, or shoot them out of fear or retaliation. These practices have led to severe population declines.

Conservation efforts

Efforts to conserve orangutans are underway. Numerous organizations are fighting to protect the existing habitats and rehabilitate orphaned or injured orangutans.

These include Borneo Orangutan Survival (BOS) Foundation, Orangutan Foundation International (OFI), and Sumatran Orangutan Conservation Programme (SOCP).

The BOS Foundation rehabilitates and reintroduces orangutans back into protected forests. The OFI focuses on protecting orangutan habitats and supports research and education about orangutans. The SOCP works specifically on the Sumatran orangutan’s conservation.

These groups also fight against illegal activities like hunting and capturing orangutans. They provide local communities with education about the importance of orangutans and their role in the ecosystem.

Help needed from both governments and consumers

Consumers worldwide can also help by choosing products made with sustainable palm oil. By doing this, we can support companies that commit to deforestation-free palm oil production.

Governments also play a crucial role in orangutan conservation. Stricter laws against deforestation and harsher punishments for illegal hunting can significantly help protect these creatures.

Moreover, government-led reforestation projects can help restore orangutan habitats. These initiatives are vital for orangutan survival and the health of our planet.

In conclusion, the orangutan’s conservation status is critical. Their survival depends on urgent, concerted efforts from governments, conservation groups, and individuals. We must all take part in the fight to protect these incredible creatures, our forests, and our planet’s future.

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