Monkeys negotiate with stolen goods, and elephants discern human words — the astonishing adaptations of animals

Monkeys Learn "Hostage Negotiation," Elephants Discern "Human Differences"—When Animals Adapt to Human Society

Monkeys snatch sunglasses and smartphones from tourists and wait for food offerings in exchange for their return. Meanwhile, elephants can discern whether approaching humans are a threat just by listening to their voices. At first, these stories might sound like jokes. However, these behaviors are not merely "cute incidents." Researchers are seriously studying these cases as examples of how wild animals adapt remarkably flexibly to human-altered environments, acquiring the wisdom needed to survive.

The German magazine Spiegel highlighted two symbolic examples of "animals adapting to humans." One is the long-tailed macaques living around the Uluwatu Temple in Bali, Indonesia, and the other is the African elephants in Kenya. What they have in common is that these animals do not see humans merely as "background" but as entities whose behavior should be predicted, and in some cases, utilized or avoided. This represents a modern adaptation strategy where the boundary between the wild and human society has become blurred.

Let's first look at the monkeys in Bali. The long-tailed macaques at Uluwatu Temple have long been known for snatching tourists' glasses, hats, wallets, and smartphones. What's important is that this doesn't end as mere theft. The monkeys don't immediately destroy or discard the stolen items; instead, they hold onto them, waiting for humans to offer food. If the conditions are right, they return the stolen goods. This series of actions is referred to in research as "robbing and bartering," analyzed as a rather unique behavioral pattern observed in natural environments.

A study published in Scientific Reports in 2022 organizes this behavior into three consecutive stages: ① stealing items from humans, ② holding onto them for a while, and ③ returning them in exchange for food. The research team views this not as simple mischief but as a behavior sequence established through interaction with humans. Moreover, this behavior is not commonly observed throughout Bali but has been particularly studied in the Uluwatu population. This suggests that it is more likely a behavior formed and inherited within a specific historical relationship with humans rather than a general "instinct" of monkeys.

Furthermore, a 2021 paper in the Proceedings of the Royal Society describes this behavior as a "culturally maintained token economy." Here, a token economy refers to a state where non-edible objects function as "exchange means" to extract food. While there have been studies in laboratories where monkeys and apes use objects as tokens, in Uluwatu, this occurs in the wild and with humans. While it may be a misfortune for tourists, it is a highly stimulating case from a behavioral perspective.

Interestingly, it seems that the monkeys do not steal indiscriminately. General reports have introduced that items like electronic devices and wallets, which humans are eager to retrieve, are more highly "valued." In fact, the Guardian reported in 2021 that the Uluwatu monkeys target items of high value to humans and use them to maximize their returns. Academic research also shows differences in the extent to which different groups engage in this behavior and the ease of obtaining rewards, with groups having more frequent human contact tending to engage in more theft.

What is crucial here is that it cannot be simplistically concluded that "monkeys understand the concept of human ownership." Research indicates that monkeys learn human reactions and empirically understand which items, when stolen, will prompt humans to offer food. In other words, rather than linguistically understanding the rules of human society, they likely perceive human attachments and behavior patterns at a behavioral level. This reflects a highly realistic and sophisticated learning ability rather than "human-like" traits.

Moreover, this behavior does not end as an individual's spontaneous idea but seems to spread socially. The 2022 paper suggests the possibility of intergenerational persistence and learning through observing other individuals, discussing the potential to view it as a "tradition of behavior." It has also been reported that young individuals, especially subadult males, frequently exhibit this behavior, and social standing is thought to influence the skill and success rate of the behavior. It can be said that as humans created tourist spots and continued to react through food, a "way of earning" became established on the monkey's side.

On social media, reactions to this topic are quite straightforward. Recent Reddit posts highlight surprise and laughter with comments like "Monkeys stealing people's phones to negotiate for food" and "The most striking story of the day." Meanwhile, some comments rationally interpret the situation, suggesting that "since humans will physically retrieve their phones if not returned, the monkeys might be learning this negotiation." While often consumed as amusing stories, many also perceive that human tourist behavior is shaping animal behavior.

Considering the reality of tourist spots, it's not all laughs. If tourists reflexively offer food, it reinforces theft for the monkeys. Conversely, if they try to retrieve the items, it increases the risk of conflict between humans and animals. A 2024 report mentioned that the management of Uluwatu Temple is working with researchers to explore how to appropriately manage this behavior. It's not that the monkeys are "bad," but rather that the interaction between humans and monkeys has mutually altered behaviors.

Now, what about the elephants? This is also a story full of surprises. A 2014 study published in PNAS showed that African elephants around Kenya's Amboseli National Park can discern differences in danger levels from human voices. The research team recorded voices of people from different ethnic groups, genders, and age groups, playing them back to wild elephant herds to compare reactions. The results showed that elephants exhibited stronger defensive reactions to the voices of Maasai men, who are more likely to pose a threat. They are not merely distinguishing "whether it's a human voice" but potentially classifying "what kind of human" in detail.

The paper concludes that elephants use multiple vocal cues such as ethnicity, gender, and age to identify the most dangerous individuals. Particularly, young adult Maasai men, who traditionally pose a threat to elephants with spears, are high-risk, while the Kamba people in the same area are relatively less dangerous. Elephants may be distinguishing these differences solely through voice. For humans, it might be as simple as "different languages" or "different tones," but for elephants, it's life-or-death information.

Again, it's important to note that saying "elephants understand human language" would be an overstatement. The research showed that elephants estimate danger from vocal features, not that they understand vocabulary or grammar. Still, the ability to identify differences within the human species as "subcategories" of predators or threats is highly advanced. The paper positions this as a detailed demonstration of human voice discrimination in large, long-lived mammals with high cognitive abilities.

On social media and forums, this elephant research has also garnered strong reactions. On Reddit, there are voices of admiration, saying, "It's different from distinguishing between lion and sheep voices. Even humans find it hard to distinguish language differences in nearby regions, so this is amazing." Meanwhile, some suggest, "They've learned about dangerous humans over a long evolutionary period." While there are many joking posts, a consistent theme is a near-awe that elephants might be observing, remembering, and classifying humans more than we imagine.

Monkeys and elephants. At first glance, these two examples might seem like entirely different stories. Monkeys "utilize" humans, while elephants "beware" of them. However, the underlying theme is the same. Humans have entered the natural world as a massive pressure, and animals are beginning to read humans precisely as targets for behavioral prediction to cope with this. Urbanization, tourism, land use changes, hunting pressure, feeding—such human activities present new cognitive challenges to animals. They respond to these challenges not just by fleeing but through learning and discrimination.

In this context, we are prone to anthropomorphize animal behavior. We might call monkeys "little rascals" or "con artists" and elevate elephants as "sages who understand human language." Of course, such metaphors make the story easier to understand. However, they also cause us to overlook many things. The exchange behavior of monkeys is based on a reward structure repeatedly provided by humans. The discrimination ability of elephants may be the result of learning the differences in danger from humans over a long experience. Therefore, what should surprise us is not the "humanization" of animals, but the fact that humans have already significantly altered their ecology and learning environments.

In this sense, these studies are both a celebration of animal intelligence and a report on the Anthropocene. As humans have rewritten the world's rules, animals are trying to adapt to these new rules. Monkeys using stolen smartphones as "bargaining chips" and elephants discerning the danger level of approaching voices have acquired ways to live in environments restructured around human presence. Rather than just being impressed by their cleverness, when we consider who created the situation that forced them to display such cleverness, the story becomes much heavier.

Animals observe us more than we think. Monkeys watch what humans do not want to lose. Elephants discern who among humans is dangerous. Even if humans think they are unilaterally studying animals, animals are also desperately studying humans. With this perspective, sunglasses snatched at tourist spots or a voice echoing across the savannah are not just rare incidents but responses from another intelligence living in the same era.

【Source URL】

・Article summarizing monkey theft exchange and elephant language discrimination
https://podcasts.apple.com/us/podcast/affen-handeln-mit-diebesgut-fische-schrumpfen-und-elefanten/id1568722007?i=1000753392383

・Research organizing the "robbing and bartering" of monkeys at Bali's Uluwatu Temple into three stages
https://www.nature.com/articles/s41598-022-11776-7

・Research positioning the behavior of Bali's monkeys as a "culturally maintained token economy"
https://royalsocietypublishing.org/doi/10.1098/rstb.2019.0677

・Abstract confirmation for the above study (PubMed)
https://pubmed.ncbi.nlm.nih.gov/33423623/

・Abstract confirmation for 2017 study on differences among monkey groups at Uluwatu Temple
https://pubmed.ncbi.nlm.nih.gov/28516338/

・General report conveying the tendency of monkeys to target high-value items for humans
https://www.theguardian.com/science/2021/jan/14/balis-thieving-monkeys-seek-bigger-ransoms-for-high-value-swag-study

・Primary research showing elephants' ability to identify human ethnic, gender, and age cues from voices (full text)
https://pmc.ncbi.nlm.nih.gov/articles/PMC3986134/

・General report summarizing elephant research
https://www.nationalgeographic.com/science/article/elephants-hear-age-gender-ethnicity-in-human-voices

・Reference source for SNS reactions to monkey research (Reddit)
https://www.reddit.com/r/interesting/comments/1r3p44x/monkeys_in_bali_have_learned_that_they_can_steal/

・Reference source for SNS reactions to elephant research (Reddit)
https://www.reddit.com/r/todayilearned/comments/29h4go/til_elephants_can_distinguish_different_human/

・Report on Uluwatu Temple's exploration of managing monkey behavior
https://www.news.com.au/travel/destinations/asia/bali/they-will-exploit-you-research-to-begin-into-how-to-manage-uluwatus-cunning-monkeys/news-story/3e49ac677772ce410a80056dd84535d6