He lives in Gunung Leuser National Park in South Aceh, Indonesia, where scientists from the Institute of Animal Behavior meticulously observe animals like Rakus, documenting their activities every two minutes.
A team of researchers led by evolutionary biologist Caroline Schuppli and cognitive biologist Isabelle Laumer were observing Rakus when they noticed he had a deep facial wound.
They believe it was caused by a neighboring male in what’s known as a “long call battle,” Laumer told Business Insider. Adult male orangutans like Rakus shout out “long calls” to attract females and let rival males know that this is their territory. However, sometimes, those verbal warnings attract males too, which can escalate to physical violence.
The research team heard a series of long calls before spotting Rakus’ wound, leading them to believe he was involved in a fight with another male, Laumer told Business Insider.
But what they saw him do over the next several days was remarkable. They published their findings in the peer-reviewed journal Nature this week.
Three days after he was hurt, Rakus began feeding on a species of liana called Akar Kuning, a potent medicinal plant that isn’t a part of an orangutan’s regular diet. The researchers observed him chewing the leaves and then applying them to his wound with his finger.
“This was, to our knowledge, the first time that a wild animal applied a potent healing plant to his own wounds,” Laumer said.
Self-medication: a rare animal behavior
Scientists have seen animals self-medicate before. For example, a group of chimpanzees in Gabon has been observed applying insects to their wounds.
But scientists aren’t sure whether these insects actually have medicinal properties, “so we don’t know if this behavior is in any way efficient or functional,” Laumer said. In other words, it’s unclear if the chimp’s behavior is intentional.
What Rakus did was different for a few reasons.
For starters, he selected a plant that his species rarely eats. Then he applied the mashed-up leaves precisely onto his wound. During this time, he also spent more than half the day sleeping, a behavior that can help wounds heal.
And, most importantly, his treatment actually worked.
“The wound healing was quite rapid, Laumer said. “Within four days, the wound was closed, and there are no signs of any infection.”
All of this evidence suggests that this was an intentional self-medicating behavior.
Seeing something like this in the wild is incredibly rare, Laumer said, because they only occur in ancient, highly evolved species, and researchers need to be in the right place at the right time.
Happy accident, or learned behavior?
If Rakus was intentionally applying medication to his wound, as the evidence suggests, how did he know to do it? We can only guess, Laumer said, but there are a few possible explanations.
It could have been a case of individual innovation, when an animal invents a new behavior for the very first time. If that’s the case, it may have been a total accident.
Rakus may have unintentionally touched his leaf-mush-covered finger to his face, and instantly felt the pain-relieving properties of the plant, Laumer explained. That would have encouraged him to repeat the behavior over and over again.
Or, it could be a learned behavior. Orangutans are known to be capable of social learning. They’re often observed “peering” at their group members, which is the act of getting very close and watching what another orangutan is doing.
It’s common for juvenile orangutans to exhibit this behavior with their mothers, for example, watching their every move to learn how to survive. So, it’s possible that Rakus may have learned this behavior from another orangutan.
But, because this is the first time this behavior has ever been observed in orangutans, scientists can’t say for sure why or how Rakus did it.
More alike than we are different
Rakus’s behavior reminds us a lot of our own behavior with medicinal plants, which could help us understand where our knack for medicinal treatment first evolved.
Our earliest shared ancestor with orangutans dates back over 10 million years, so this behavior may originate from many millions of years ago.
“It also shows how similar we are, more similar than we are different,” Laumer said. “It points to how amazing and incredibly smart these animals are, and how important it is to protect them.”
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