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Example of a Bayaka woman hunting in southern Central African Republic in 2014. Source: Max Chiswick/CC BY SA 4.0

Hunter Gatherer Society Has a Time-Tested, Secret Method to Traverse the Rainforest

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How do human foragers find food or the way home in rainforests, where heavy vegetation limits visibility, without a map, compass, or smartphone?

Researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, show that rainforest-dwelling Mbendjele BaYaka people from the Republic of Congo point to out-of-sight targets with high precision. Pointing accuracy was equally good in men and women; children’s performance improved when the sun was clearly visible in the sky. The study has been published in Proceedings of the Royal Society B .

Who are the Mbendjele BaYaka?

Knowing which direction to go in order to reach a food location or home is important for many animal species, including humans. For human foragers who travel long distances every day hunting and gathering, orientation skills are essential. Haneul Jang and her colleagues from the Max Planck Institute for Evolutionary Anthropology set out to study how the Mbendjele BaYaka people in Republic of Congo orient themselves in the dense rainforest.

To this aim, the researchers conducted more than 600 pointing tests with 54 Mbendjele BaYaka men, women, and children aged between 6 and 76 years, in which the participants were asked to point an out-of-sight target in more than 60 different rainforest locations (including the camp).

The Mbendjele BaYaka have been living in the rainforest as hunter gatherers for hundreds of years. Moreover, there is archaeological evidence that hunter gatherer groups have inhabited some parts of the rainforest for 100,000 years (although it’s uncertain if they are related to the current inhabitants.) They are sometimes referred to as Pygmies (although with some differences from other Pygmy groups) and they live as semi-nomadic hunter-gatherers.

Mbendjele BaYaka men. (libcom.org)

Mbendjele BaYaka men. ( libcom.org)

Most of the year they live in the rainforest, however they also work with agriculturalists sometimes to trade food, alcohol, money, and other goods. Some people have also begun to work with logging companies. Libcom.org provides some insight on Mbendjele BaYaka economy, stating that they have “economies based on demand-sharing,” and practice “important rituals associated with elephant hunting”.

Pointing Accuracy is Equally Good in Men and Women

Jang and her colleagues found that the Mbendjele BaYaka are highly accurate at pointing to distant and out-of-sight target locations. The researchers found pointing accuracy was equally good in men and women. Jang, lead author of the study, said:

"Gender equality in the Mbendjele BaYaka population may result in Mbendjele women’s long-distance foraging for fishing and hunting as do men. This might allow women and men to develop similar orientation abilities. Our results are consistent with previous studies that found no sex differences in orientation abilities in hunter-gatherer societies where both sexes actively travel away from home. Studies from various cultures suggest that sex differences in orientation abilities may indeed result from sex-specific mobility, and our results add to this growing body of evidence.”

"In contrast to men and women in our society, where women may still be more likely to work at home or closer to home compared to men, we observed that Mbendjele men and women travel equally far from home, and it is therefore perhaps not surprising that they score equally well in orientation tasks. The results of our study confirm how important experience is for our cognitive development", says Karline Janmaat, main supervisor of the study.

A Mendjele BaYaka woman, here carrying GPS before leaving for a hunting trip in the rainforest in the Republic of Congo. (© Haneul Jang)

A Mendjele BaYaka woman, here carrying GPS before leaving for a hunting trip in the rainforest in the Republic of Congo. (© Haneul Jang )

Libcom.org also emphasizes the importance of rainforest hunting for Mbendjele BaYaka people. Traditional they have spent “at least four months a year hunting and gathering in the forest; strongly identifying with and preferring forest life; contrasting the “forest world” to the “village world.”” With the rainforest playing such a prominent role in traditional Mbendjele BaYaka lives, it is clearly important that they have a method to orient themselves in that environment.

Learning to Navigate from an Early Age

Interestingly, Jang and her colleagues found that at around age six, Mbendjele BaYaka children already performed as accurately as adults in the pointing tests when the tests were conducted close to the camp. Moreover, the researchers found that when the sun was visible in the sky, children’s pointing accuracy increased substantially, especially in more distant and less familiar areas. Adults, on the other hand, performed accurately throughout their range also on cloudy days.

"Unlike the adults, who have a very good sense of direction in distant areas even if they cannot see the sun’s position , the children make large pointing errors in less familiar areas when they cannot see the sun. However, if they can see the sun, children’s performances improve considerably", says Jang.

"The Mbendjele BaYaka people live in flat lowland rainforests where orienting oneself is challenging due to heavy vegetation and the absence of distant landmarks like mountain peaks. People who live in such an environment may need to start learning how to use the position of the sun to ascertain a direction from a very early age."

“People who live in such an environment may need to start learning how to use the position of the sun to ascertain a direction from a very early age.” (CC0)

People who live in such an environment may need to start learning how to use the position of the sun to ascertain a direction from a very early age.” ( CC0)

The First Known Case of Sun Compass Use

According to the authors, this study provides the first behavioral evidence for sun compass use in humans. "We know that bees can use the sun to navigate, but surprisingly there has been no scientific evidence yet that humans may have this skill, too, and that children may develop this skill by age six", says Janmaat.

"Our study shows that there is still so much to discover and with a high level of urgency. All forests inhabited by human rainforest foragers in Congo have been sold to foreign companies, causing these people to lose not only their foraging grounds, but their intriguing navigation skills as well."

Young Mbendjele boy of age 8.5 years pointing at a food location. Here with researcher Haneul Jang in the tropical rainforest of the Republic of Congo. (© Karline Janmaat)

Young Mbendjele boy of age 8.5 years pointing at a food location. Here with researcher Haneul Jang in the tropical rainforest of the Republic of Congo. (© Karline Janmaat)

Although the Max Planck press release doesn’t go into detail on how the Mbendjele BaYaka use their ‘sun compass’ an article titled ‘The sun compass revisited,’ published in Animal Behavior in 2014, provides some insight on how others use this method:

“Having set a heading by whatever means, animals, like aviators, must make continued use of directional information in order to maintain that heading. Although it is possible in principle to use a compass for this task, the directional information that is required to maintain a heading need not involve any absolute geographical reference at all. The value of this simpler kind of directional information will be familiar to anyone who has strayed from a footpath in dense forest, flown through cloud or dived in murky waters. In such circumstances, it may not matter that you know which way is north or south, but it matters greatly that you can monitor your heading so as to maintain a straight course in a given direction, and reverse it accurately if required. Surface-bound animals may use idiothetic cues associated with walking on a substrate to achieve this […] the sun and its attendant cues, such as the polarization axis of the sky, provide a reliable celestial heading reference, analogous to the inertial heading reference provided by the gyroscope in an aircraft's heading indicator.”

Top Image: Example of a Bayaka woman hunting in southern Central African Republic in 2014. Source: Max Chiswick/ CC BY SA 4.0

This article was first published as a press release titled Finding one’s way in the rainforest and has been edited for style and length.

Source: Haneul Jang, Christophe Boesch, Roger Mundry, Vidrige Kandza, Karline R. L. Janmaat

Sun, age, and test location affect spatial orientation in human foragers in rainforests

Proceedings of the Royal Society B, 24 July 2019, DOI: 10.1098/rspb.2019.0934

Max Planck Institute, July 23, 2019 Finding one’s way in the rainforest

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