Tag Archives: chimpanzees

Wild Chimpanzees May Get Tipsy from Fermented Fruit

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Two male chimpanzees consuming fruit resembling evergreen plums from Parinar excelsa trees in Taï National Park, Ivory Coast.

Aleksey Maro/UC Berkeley

Wild chimpanzees forage for fermented fruits, consuming the equivalent of two glasses of wine daily, adjusted for their body size relative to humans.

It has long been recognized that many primates, including chimpanzees, consume substantial alcohol from diets rich in ripe fruits and other vegetation. Some suggest this could explain the human affinity for alcoholic drinks.

Alec Malo at the University of California, Berkeley, and his team sought to quantify the ethanol intake of chimpanzees by collecting fruits from two locations frequented by wild populations and measuring their alcohol content.

The research focused on two habitual populations: Eastern chimpanzees (Pan troglodytes schweinfurthi) in Ngogo, Uganda, and Western chimpanzees (Pan troglodytes verus) in the Tai Chimpanzee Project, Ivory Coast.

The researchers first observed the fruits being consumed by the chimps via camera traps and only collected those they confirmed were targeted. For fruits in the canopy, they gathered only samples that had recently fallen or were seen in the fall.

Eastern chimpanzees preferred ripe fruits from fig trees (Ficus mukuso), while Western chimpanzees often favored Guinea plums (Parinari excelsa) and fruits from the bitterburk tree (Sacoglottis gabonensis).

The study determined an overall alcohol concentration of roughly 0.3-0.4% in the fruit. Wild chimpanzees consume about 10% of their body weight in fruit pulp daily, Malo explains. They calculated that the chimpanzees ingest around 14 grams of pure ethanol per day at both sites.

A 125 ml glass of wine at 12.5% contains about 12 grams of ethanol. “This also accounts for the fact that chimpanzees average 40 kilograms versus 70 kg for humans,” says Malo. “Thus, we can assert that chimpanzees consume the equivalent of two glasses of wine each day.”

While chimpanzees and humans diverged millions of years ago, both likely encountered fermented fruits similarly, Malo notes.

“These findings indicate that our ancestors were similarly exposed to dietary alcohol,” he states. “The drunken monkey hypothesis suggests this exposure may have evolved an association between alcohol consumption and the rewards from fruit sugars, explaining humanity’s attraction to alcohol today.”

To gauge how much alcohol chimpanzees have in their systems, Malo collected urine samples beneath them, using an umbrella for protection. He’s currently analyzing this data.

Miguel Rulente, from the University of Girona in Spain and not part of the study, states that this research offers the first quantitative estimate of daily ethanol consumption in wild chimpanzees. “It supports the notion that alcohol exposure has deep evolutionary roots within primate diets and possibly influenced human evolution,” he asserts.

However, he cautions that this study has limitations in its implications for humans. “Unlike humans, ethanol consumption in apes is incidental and not intentional, making the leap from natural exposure to our species’ addiction challenging,” he adds.

Neanderthals, Ancient Humans, Cave Art: France

Join new scientist Kate Douglas on a captivating exploration of key Neanderthal and Upper Paleolithic sites across southern France, spanning from Bordeaux to Montpellier.

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Source: www.newscientist.com

Chimpanzees Utilize Healing Plants for Wound Care

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New research has revealed that wild chimpanzees are capable of self-medicating their wounds with plants, assisting injured companions, and freeing others from traps set by human hunters.

This behavior, documented in a study published in the journal Frontiers of Evolution and Ecology on Wednesday, offers new insights into the evolutionary roots of human medicine.

Over approximately eight months, the study combined video footage and photographs with historical data, revealing that chimpanzees engage in actions like biting plants, applying leaves to wounds as makeshift bandages, and grooming wounds of fellow animals. Observers noted a chimpanzee pressing a leaf against its wound for treatment.

The findings contribute to ongoing discussions about whether altruistic behaviors are exclusive to humans, as they show that even chimpanzees without familial ties can exhibit care toward one another.

Wild chimpanzees in Uganda grooming.
Elodie Freymann

“Humans often pride themselves on being unique in their capacity for empathy and altruism,” says Elodie Freyman, a postdoctoral researcher at Oxford University and the study’s lead author. “These animals demonstrate that they can identify others in need and respond appropriately.”

Chimpanzees and bonobos, the closest genetic relatives to humans, bolster the argument that healthcare concepts may have existed millions of years prior to the emergence of Homo sapiens.

“Our shared ancestors likely exhibited these caring behaviors,” Freyman stated.

An increasing number of studies indicates that various animal species can self-medicate with differing levels of sophistication. For instance, elephants have been observed to consume specific leaves for medicinal purposes, hinting that animals might be addressing health issues like digestion.

As research on animal medicinal behaviors expands, experts believe it provides crucial insights into our own evolutionary past.

“Evidence of healthcare behaviors exists among our ancestors, dating back to pre-Neanderthals, but the evolutionary pathways of such explorative behaviors remain unclear,” remarked Alessandra Mascaro, a primate researcher and doctoral candidate at the University of Osnabrueck in Germany. “We are only beginning to uncover these complexities.”

In 2022, Mascaro published findings illustrating that Gabonian chimpanzees applied insects to their own wounds and anticipates that further observations will clarify how these behaviors evolved.

Studying chimpanzee self-medication poses challenges due to the rarity of such behaviors.

Freyman dedicated two months to researching chimpanzees in Budongo Forest, Uganda, where observing these animals can be both physically taxing and demanding.

Wild chimpanzees in Uganda grooming.
Elodie Freymann

“Some days involve sitting at the base of a tree for hours, while others might have you stuck in a muddy hole while trying to observe them. The day’s tasks depend heavily on the group’s activities.

During her fieldwork, Freyman noted numerous instances of care behaviors among chimpanzees. She also discovered historical observational records from previous studies that revealed behaviors not documented until now, indicating a pattern of medicinal practices dating back to the 1990s.

“Collating these observations paints a remarkable picture of chimpanzee care,” she remarked.

From her findings and historical records, Freyman documented 41 instances of chimpanzee wound care, including four cases involving unrelated individuals.

“These results suggest that prosocial behaviors among nonkin may be more widespread than previously recognized,” noted Isabel Laumer, a cognitive biologist at the Max Planck Institute for Animal Behavior in Germany, who was not part of this study. “Further research is essential.”

Mascaro, who has studied chimpanzee healthcare behaviors in Gabon, acknowledged that the new findings from Uganda show similar medicinal behaviors across different populations of chimpanzees.

“Prior to this, we had limited knowledge about chimpanzees in that part of Africa,” Mascaro stated.

The phenomenon of self-medication has also been observed in other primates. Last year, Laumer documented that Indonesian orangutans apply leaves to facial wounds as a remedy for injuries sustained during conflicts. The plants they utilize often possess pain-relieving properties recognized by humans.

This body of research broadly indicates that primates are capable of identifying and utilizing plants with medicinal qualities.

“Chimpanzees consider forests not only as a food source but also as a repository for medicinal resources,” Freyman emphasized, underscoring the importance of preserving forest ecosystems.

She suggested that humans may have learned about medicinal plants from these primates, and that pharmaceutical companies could benefit from studying animal behavior to discover valuable medical compounds in the future.

“If you wish to refine the knowledge of these remarkable medicinal resources, observing and learning from animals is an effective, ethical, and responsible approach,” Freyman concluded.

Source: www.nbcnews.com

Chimpanzees Utilize Various Linguistic Attributes to Communicate About One Another

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Recent research indicates that wild chimpanzees have established a more nuanced communication system than previously thought, employing various mechanisms that merge vocalizations to convey new meanings.

These aspects of chimpanzee communication are detailed in studies published in Friday Journal Science Advances, resembling some basic elements of human language.

Researchers examined recordings from three groups of chimpanzees residing along ivory shores, revealing that they can combine vocalizations much like humans use idioms and rearrange words to form new phrases.

This study marks the first documentation of such complexity in non-human communication systems, suggesting that chimpanzees’ capabilities reflect an evolutionary turning point between basic animal communication and human language.

“The ability to combine sounds to create new meanings is a hallmark of human language,” stated Catherine Crockford, a researcher at the Max Planck Institute for Evolutionary Anthropology and co-director of the Tai Chimpanzee project. “It is crucial to explore whether similar capabilities exist in our closest living relatives, chimpanzees and bonobos.”

Another study published last month provided similar evidence indicating that bonobos can also combine calls to form phrases. Together, these studies imply that both species are evolving fundamental components of human language.

Bonobos and chimpanzees are the species most closely linked to humans in evolutionary history, suggesting all three may have derived from a common ancestor with this capability.

“Our findings indicate a highly generative vocal communication system that is unmatched in the animal kingdom. This aligns with recent discoveries about bonobos and implies that complex combinatorial abilities may have already existed in a common human ancestor.”

Researchers identified these new complexities in chimpanzee vocal systems by tracking specific animals in the field from dawn to dusk for approximately 12 hours daily, capturing the sounds they produced and their interactions with others in the group. They documented over 4,300 vocalizations from 53 wild chimpanzees.

While observing the vocalizations, researchers noted the activities, social interactions, and environmental changes occurring simultaneously, indicating whether the chimpanzees were eating, playing, or encountering predators.

The team performed statistical analyses on particular two-call combinations, such as “bark followed by bark,” recorded across various animals.

Their findings revealed that chimpanzees combine sounds to reference everyday experiences, with combinations that can express a range of meanings.

Simon Townsend, a professor at the University of Zurich who studied primate cognition and contributed to the bonobo study, noted that he wasn’t involved in this particular research.

He suggested that the common evolutionary ancestors of bonobos, humans, and chimpanzees likely possessed this ability.

“This suggests that our linguistic capabilities were already developing about 6-7 million years ago,” Townsend stated, referring to the time when these species likely diverged in the evolutionary tree.

Not all primates showcase such intricate communication. Townsend noted that forest monkeys, with simpler social structures, primarily utilize vocalizations to address predatory threats.

However, he believes that increasingly larger and more intricate social groups—a common trait among great apes and humans—have catalyzed the evolution of more sophisticated communication and ultimately, language.

For bonobos and chimpanzees, “Their biggest challenge is managing their intricate social environment. They exist in larger groups… There are conflicts, reconciliations, territorial disputes, and intergroup interactions. Vocalization is likely one evolutionary response to navigating these complex social dynamics.”

In human language, syntax refers to a set of rules that create a system capable of expressing infinite meanings.

“Syntax pertains to conveying increasingly precise and sophisticated information, which probably becomes necessary as social interactions grow more complex,” Townsend stated.

Source: www.nbcnews.com

Scientists in the Dark as Chimpanzees are Photographed with Drums in the Wild

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Recent studies indicate that wild chimpanzees exhibit a natural talent for drumming, tapping to the rhythms present in their environment.

A significant international collaboration involving researchers from Europe, Africa, and America has concluded that chimpanzees drum with intentional rhythms, striking the trunks and roots of trees as they move and vocalize. These discoveries offer scientists valuable insights into the potential origins of human musicality.

https://c02.purpledshub.com/uploads/sites/41/2025/05/Drumming-Bout-Vesta-Eleuteri.m4v
An adult male western chimpanzee from the Thai East community drumming on a wooden buttress in the Thai forest (Côte d’Ivoire).

“Humans are fundamentally rhythmic beings,” stated Professor Katherine Hofighter from St Andrews University in an interview with BBC Science Focus. “Rhythms permeate our music, dance, and songs, and even in our conversations. This may be part of our evolutionary inheritance, as it is a universal trait among humans.”

To investigate the roots of this rhythm, researchers turned to our closest living relatives.

“Since both language and music are non-fossilized skills, it’s impossible to find them in the geological record and trace their evolution,” remarked the study’s lead author, Vesta Eleuteri from the University of Vienna in an interview with BBC Science Focus. “We must examine other species and investigate the foundational elements that may precede the development of language and music.”

Hobaiter added: “This demonstrates that the elements of rhythm existed long before humans evolved into humans.”

Four images portray an eastern chimpanzee from the son’s community in Budongo Forest (Uganda) drumming with a wooden buttress. – Credit: Adrian Soldati

Recently published research in Current Biology represents the culmination of years of meticulous observations and analyses, encompassing 371 recorded chimpanzee drumming encounters across 11 wild chimpanzee communities in West and East Africa.

“People often underestimate the time commitment required to gather this data,” explains Hobaiter. “While the forest is my happy place, it sometimes means decades of research at each location.”

All recordings were carefully collected, coded, and analyzed. The researchers measured the duration of each drumming sequence, the intervals between hits, and the variability of the rhythms, concluding that these rhythms were not random.

Moreover, individual chimpanzees showcase their own unique styles of drumming. Regional variations also exist among different chimpanzee communities and subspecies.

For instance, West African chimpanzees tend to maintain regular spacing between drum hits, whereas East African chimpanzees display a mix of shorter and longer rhythms.

While the reasons for these differences remain unclear—Hobaiter mentioned they “got a bit crazy”—Eleuteri proposed these variations might stem from social or cultural differences among chimpanzee subspecies.

Habaiter emphasized that these rhythmic distinctions highlight the importance of conservation efforts: “Every group of chimpanzees holds unique significance.”

“Recognizing that distinct populations or subspecies have unique differences is crucial for preservation,” she asserted. “Losing any group could result in the disappearance of a unique culture, music, or rhythmic heritage that can never be restored.”

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About Our Experts

Vesta Eleuteri is a doctoral student at the Faculty of Behavior and Cognitive Biology at the University of Vienna, focusing on African elephant communication. She has previously researched chimpanzee drumming at the University of Rome and the University of St Andrews.

Katherine Hofighter is a professor of psychology and neuroscience at St. Andrews University, with 15 years of experience studying primates in Uganda and across Africa. Her research group, The Wild Minds Lab, emphasizes long-term field studies on communication and cognition in wild African apes. She has spent nearly six months in the field and has recently established new research sites in Uganda (Bugoma Primate Conservation Project) and Guinea (Moenvating Chimpanzee Project).

Source: www.sciencefocus.com

Chimpanzees Share “Fundamental Elements of Musical Rhythms” with Humans

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Young Chimpanzee Drumming in Guinea

Cyril Ruoso/Naturepl.com

Musicality may have originated from a shared ancestor of chimpanzees and humans, given the similarities in their drumming techniques.

Katherine Hoheiter at The University of St Andrews and her research team analyzed 371 instances of drumming from two of the four subspecies of chimpanzees in Africa: Western chimpanzees (Pantroglogistics Vers) and Eastern chimpanzees (Pan troglodytes schweinfurthi).

They utilize their hands and feet, often on buttress roots, creating rapid rhythms mainly during rest, travel, or during displays of threat.

Hoheiter mentions that while capturing chimpanzee drumming is common, the rainforest poses significant research challenges, and gathering data for some populations took decades.

Ultimately, researchers found that chimpanzees drum significantly faster than most humans. “The longest drumming event we recorded exceeded five seconds, while the shortest was less than 0.1 seconds,” notes Hoheiter. “Chimpanzees also tend to repeat these beats, especially while traveling.”

Despite the contrasts between chimpanzee and human drumming, chimpanzees exhibit some “core components of human musical rhythms,” according to team member Vesta Eleuteri from the University of Vienna.

“They employ recognizable rhythms present in various musical cultures, which contrasts with randomly played beats. These consist of hits that are evenly spaced, akin to clock ticks,” she elaborates. “Moreover, we discovered that the Eastern and Western chimpanzee subspecies, residing on different sides of Africa, exhibit distinct rhythmic patterns.”

Eleuteri explains that Eastern chimpanzees alternate between short and long intervals between beats, while Western chimpanzees maintain equally spaced hits. Additionally, these chimpanzees initiate drumming more quickly and use more hits to commence drumming early during a unique pant-hoot call.

Miguel Rulente from the University of Girona finds the notion that different subspecies display unique drumming styles compelling. “These patterns suggest the potential for not just individual idiosyncrasies but also cultural distinctions in how groups utilize drumming as communication tools.”

It is well understood that rhythm plays a crucial role in human social interaction, whether through music, dance, or even conversational rhythms, explains Hoheiter. “I’m not implying that chimpanzee drumming reflects the sophistication of modern human rhythms. However, this research is the first to show that we share fundamental rhythmic elements, suggesting that rhythms are intrinsic to our social environment even before we evolved into humans.”

“Previously, it was claimed that rhythmicity was exclusive to humans,” states Gisela Kaplan from the University of New England. “However, a growing body of evidence suggests this is not the case.”

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Source: www.newscientist.com

New Study Reveals Differences Between Your Brain and Chimpanzees

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We share 98.8% of DNA with our closest living relatives, chimpanzees. However, despite this almost identical genetic blueprint, chimpanzees have not built civilizations, fought wars, or mastered the art of Tiktok dance routines.

But what exactly makes us stand out? Now, neuroscientists may finally have the answer.

New research published in the journal jneurosci looks at new data from the brains of humans, chimpanzees, and macaques.

“We were interested in finding things that ticked different brains.” Professor Logier Mars, the study co-author said to BBC Science Focus. “And the human brain is something we were particularly interested in, for obvious reasons.”

According to Mars, most studies comparing human brains with other animal brains tend to focus on factors such as overall size, the size of a particular region, or the number of neurons. “But our philosophy is that if we really want to understand what is going on, we need to look into how our brains are organized,” he said.

With that approach in mind, Mars and his team set out to investigate. Similar to the scans used in hospitals, published MRI data were used to create a “connectivity blueprint” for three different species of brains. These blueprints essentially map out whether different regions of the brain communicate with each other.

One area the team expected to find a difference was in the prefrontal cortex. This region is related to complex thinking, planning, and decision making.

This area, often referred to as the “personality center” of the brain, plays an important role in regulating emotions and teaching behaviors. At first glance, it seems to be an obvious place to search for the essence of what makes us human. In fact, this study revealed that this region exhibited more connectivity than in other species.

But was that the whole story?

This image highlights the (red) behavioral domains of the left and right hemispheres showing high divergence after comparison. -Bryant et al. , Jneurosci 2025

“The prefrontal cortex is where researchers tend to see when they look for something unique about humans,” Mars said. “But we have found a difference in many places in the cortex of time just above your ears.

Temporal cortex plays an important role in the processing of sensory information – especially visual, sound, and language. Given our highly social and cooperative nature, it is probably not surprising that these areas are connected more intricately in the human brain.

“We are a very social and cooperative species,” explained Mars. “So these properties are likely the driving force behind the changes we observe.”

All of these suggest that there is no single definition switch that makes humans human. Some believe that highly evolutionary events have led us to dominance, but reality can be more complicated.

Like relatives not too far in the trees, we are the result of the progressive, widespread evolutionary changes that have shaped us over time.

Or, as Mars said, “There’s nothing big that makes us different.”

About our experts

Rosier Mars is a professor of neuroscience at Oxford University. His work focuses on the differences between primate brains, especially humans. Mars’s research is published in the following journals: Natural Communication, Frontiers of human neuroscience, and Science.

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Source: www.sciencefocus.com

Chimpanzees and bonobos engage in genital rubbing to alleviate social tension

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Male chimpanzees may have sexual contact during stressful periods

Jake Brooker/Chimhunsi Wildlife Orphanage Trust

Some chimpanzees seem to use sexual behaviors like genital rubbing to manage stressful situations. This shows that our closest living relatives – or in fact, as we thought, isn’t that different from highly sensitive bonobos.

Jake Brooker Durham University in the UK and his colleagues investigated the sexual behavior of non-human primates Rolaya Bonobo Sanctuary The Democratic Republic of the Congo and Chimhunsi Wildlife Orphanage Trust In Zambia. Both sanctuaries contain a mixture of wild and captive-born apes, allowing them to roam freely and forage within them.

Researchers observed 53 bonobos (Pampaniscus) It spans three groups: Lola Ya Bonobo and 75 chimpanzees (Pantrogloid) across two groups of chimhunsi over the course of the feeding event of events, including swings distributing limited supply of peanuts to specific regions.

“Bonobos and chimpanzees both live in extremely complex social structures. Zanna Clayat Durham University. Predicting such feeding events can be stressful due to the competition for those who will first reach the food.

Researchers observed 107 instances of genital contact in bonobos and 201 instances of chimpanzees five minutes before 45 feeding events in five groups.

“This involves placing your hands or feet in another primate's biogenic area, and it could also involve the genital organs that touch each other, like the bonobo's very well-known genital friction behavior,” says Brooker.

This study revealed differences between species. “We found that sex frequency in these situations was more common in other women and female bonobos, but more common among chimpanzee men,” says Clay. It may be related to the fact that bonobos live in patriarchal groups, but chimpanzees live in patriarchal groups, she says.

“By using sex as a social tool to navigate all kinds of social issues, bonobos have given them a bit of a reputation as a kind of sexy hippie ape,” says Clay. “This study shows that the differences between the two species are not as large as previously assumed. Chimpanzees are known to be aggressive and violent, but in reality they have a truly rich repertoire of behaviors used to manage social life.”

“Chimpanzees definitely draw PR short straws compared to bonobos.” Matilda Brindle At Oxford University.

Chimpanzees use sex in ways that go beyond breeding, unlike human sexuality, but we don’t just have sex for breeding, says Clay. for example, Stress reduction It was given as a reason for people to have sex.

Kit Opie At the University of Bristol in the UK, I wonder if the same level of behavior can be seen in wild environments rather than sanctuaries.

The work may also shed light on our last common ancestors, who lived around five to seven million years ago, before humans branch out from dicks and bonobos, he says.

“If we consider that all three use sexual behaviors to navigate social relationships, it is likely that the common ancestors we share did too,” Brindle says.

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Source: www.newscientist.com

Research: Urination in chimpanzees can be contagious

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The decision to urinate involves a complex combination of both physiological and social considerations. However, the social aspects of urination remain largely unknown. More specifically, timing urination (i.e., synchrony) and triggering urination by observing similar behavior in others (i.e., social contagion) occur in humans across different cultures. It is thought that it probably occurs in animals other than humans as well. in new paper in diary current biologyScientists have discovered that urination is socially contagious in chimpanzees, one of our closest relatives, measured through more than 600 hours of total outbreak records in 20 captive chimpanzees at Japan's Kumamoto Sanctuary. is reported. Their results suggest that socially contagious urination is an overlooked aspect of social behavior and potentially widespread.

<div id="attachment_102786" style="width: 590px" class="wp-caption aligncenter"><a href="https://cdn.sci.news/images/enlarge12/image_13596e-Chimpanzees.jpg"><img aria-describedby="caption-attachment-102786" class="wp-image-102786 size-full" src="https://cdn.sci.news/images/2025/01/image_13596-Chimpanzees.jpg" alt="A chimpanzee eats leaves in the Kumamoto Preserve. Image credit: Onishi et al., doi: 10.1016/j.cub.2024.11.052." width="580" height="436" srcset="https://cdn.sci.news/images/2025/01/image_13596-Chimpanzees.jpg 580w, https://cdn.sci.news/images/2025/01/image_13596-Chimpanzees-300x226.jpg 300w" sizes="(max-width: 580px) 100vw, 580px"/></a><p id="caption-attachment-102786" class="wp-caption-text">A chimpanzee eats leaves in the Kumamoto Preserve. Image provided by: Onishi <em>others</em>., doi: 10.1016/j.cub.2024.11.052.</p></div>
<div>
    <p>"In humans, urinating together can be considered a social phenomenon," said Kyoto University researcher Ena Onishi, lead author of the study.</p>
    <p>There is an Italian proverb that says:<em>People who don&#39;t pee at work are either thieves or spies.</em>&#39;(<em>Chi non piscia in compagnia o è un ladro o è una spia</em>), In Japanese, the act of urinating with another person is called ``.<em>connection</em>""</p>
    <p>"This behavior has been expressed in art across cultures for centuries and continues to appear in modern social contexts."</p>
    <p>"Our study suggests that this phenomenon may have deep evolutionary roots."</p>
    <p>"We found that chimpanzees, our closest relatives, tend to urinate in response to the urination of nearby individuals."</p>
    <p>Researchers decided to study this behavior after noticing that the chimpanzees at the sanctuary seemed to urinate at about the same time.</p>
    <p>It reminded me of human behavior and I thought it might be comparable to a contagious yawn.</p>
    <p>To find out, they recorded the urination behavior of Kumamoto chimpanzees over 600 hours, including 1,328 urination events.</p>
    <p>They analyzed observational data to see if the chimpanzees&#39; pees were significantly synchronized in time.</p>
    <p>They also investigated whether it was influenced by nearby individuals or shaped by social factors.</p>
    <p>The evidence showed that micturition events during observation were significantly more synchronized than would be expected if the chimpanzees simply urinated at random times on each other.</p>
    <p>Physical proximity to the first urinator also increased the likelihood of contagious urination.</p>
    <p>Interestingly, individuals with lower dominance rankings were more likely to pee when others were peeing.</p>
    <p>This finding suggests that urinary patterns are influenced by social class and that behavior tends to flow along dominant structures.</p>
    <p>"We were surprised to find that transmission patterns are influenced by social status," Dr. Onishi said.</p>
    <p>"Since there have been no previous studies of contagious urination in any species, we draw parallels with contagious yawning, another semi-voluntary physiological behavior."</p>
    <p>"Based on this, we initially expected that the social effects might be similar to those seen with yawns, such as stronger contagion between socially close pairs."</p>
    <p>"However, our results showed no evidence of effects related to social intimacy."</p>
    <p>"Instead, we observed a clear effect of social status, with lower status people being more likely to defer to others&#39; urination."</p>
    <p>"This was an unexpected and interesting result because it opens up multiple possibilities of interpretation," said lead author Dr. Shinya Yamamoto, also from Kyoto University.</p>
    <p>"For example, it may reflect covert leadership in synchronizing group activities, strengthening social bonds, or attentional biases between subordinate individuals."</p>
    <p>"These findings raise interesting questions about the social function of this behavior."</p>
    <p><span style="color: #808080;">_____</span></p>
    <p><span style="color: #808080;">Ena Onishi <em>others</em>. 2025. Socially contagious urination in chimpanzees. <em>current biology</em> 35 (2): R58-R59;doi: 10.1016/j.cub.2024.11.052</span></p>
</div>

Source: www.sci.news

Chimpanzees show signs of increasing technological advancement through their cultural development.

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Some chimpanzees use sticks to catch termites

Manoj Shah/Getty Images

Chimpanzees in the wild, just like humans, seem to learn skills from each other and improve their skills from generation to generation.

In particular, young females who migrate between groups bring cultural knowledge with them, allowing groups to combine new and existing techniques to become better at foraging. Such “accumulated culture” means that some chimpanzee communities are becoming more technologically advanced over time, even if very slowly, he says. Andrew Whiten At the University of St. Andrews, UK.

“If chimpanzees have cultural knowledge that the community they migrate to doesn’t have, they may pass it on in the same way they pass on genes,” he says. “And that’s where the culture is built.”

Scientists already knew that chimpanzees use tools in sophisticated ways and can pass on that knowledge to their offspring. However, compared to humans’ rapid technological development, chimpanzees did not seem to have advanced in previous technological innovations, Whiten said. The fact that chimpanzee tools are often made from biodegradable plants makes it difficult for scientists to track chimpanzee cultural evolution.

Cassandra Gunasekaram Researchers at the University of Zurich in Switzerland thought they might be able to apply genetic analysis to this puzzle. Male chimpanzees remain in their home regions, but young females leave their home communities to search for mates elsewhere. She wondered if these women were bringing their skill sets to the new group.

To find out, she and her colleagues obtained data from 240 chimpanzees representing all four subspecies. previously collected by other research groups At 35 research facilities in Africa. The data included precise information about what tools, if any, each animal used and their genetic connections over the past 15,000 years. “Genetics gives us a kind of time machine to see how culture was transmitted among chimpanzees in the past,” Whiten says. “It’s quite a revelation to have new insights like this.”

Some chimpanzees used complex combinations of tools to hunt termites, including drill rods and fishing brushes made by pulling plant stems between their teeth. The researchers found that even if they lived thousands of miles apart, chimpanzees with the most advanced tool sets had the same level of performance compared to chimpanzees that used simple tools or chimpanzees that did not use any tools at all. They found that they were three to five times more likely to share DNA. Also, the use of advanced tools is more strongly associated with women’s migration compared to the use of simple tools or no tool use.

“Our interpretation is that these complex toolsets were actually invented, perhaps building on earlier, simpler forms, so we learned from the community that first invented them and from all the others along the way. “We need to rely on women’s transmission to communities,” she says. Whitens the skin.

“This shows that complex tools rely on social interactions between groups, which is very surprising and interesting,” says Gunasekaram.

thibault gruber The University of Geneva professor said he was not surprised by the results, but said the definition of complex behavior was debatable. “Having worked with chimpanzees for 20 years, I would argue that cane use itself is complex,” he says.

For example, his own team discovered what is called a cumulative culture of chimpanzees that make sponges from moss instead of leaves. This is not very complicated, but Works more efficiently to absorb mineral-rich water from the clay pores.. “It’s not a matter of more complexity, it’s just that some technologies build on previously established technologies,” he says.

Gunasekaram says that cumulative culture in chimpanzees is still significantly slower than in humans, likely due to differences in chimpanzees’ cognitive abilities and lack of language skills. Additionally, chimpanzees interact far less with others outside their community than humans, and have fewer opportunities to share culture.

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Source: www.newscientist.com

Research Shows Chimpanzees Excel at Challenging Computer Tasks in the Presence of Others

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Human cognitive abilities can be greatly influenced by the presence of an audience. Although often associated with reputation management, which is thought to be unique to humans, it is unclear to what extent this phenomenon is common to non-human animals. To investigate such audience effects in chimpanzees, researchers Kyoto University Contains performances by 6 people Chimpanzee (pan-troglodytes) Over a period of 6 years, we conducted experiments on three different numerical touch screen tasks of varying difficulty and cognitive demands, in a variety of audience compositions. The results showed that chimpanzee performance was influenced by the number and type of audience present.

To investigate whether chimpanzees' task performance is influenced by the presence of an audience, Lin others. analyzed multiple chimpanzee cognitive task data across different types of tasks. Image provided by: Akiho Muramatsu

“It was very surprising to discover that chimpanzees were influenced by the audience, and even by the human audience, in their task performance,” said Kyoto University researcher Dr. Kristen Lin.

“Although we might not expect chimpanzees to particularly care whether other species are watching them perform a task, chimpanzees are influenced by human spectators even depending on the difficulty of the task. The fact that it looks like this suggests that this relationship is more complex than we thought and initially expected. ”

Lin and his colleagues wanted to find out whether the audience effect often attributed to reputation management in humans also existed in non-human primates.

People knew that paying attention to who was looking at them, sometimes unconsciously, would affect their performance.

Chimpanzees live in hierarchical societies, but it was not clear to what extent they were also influenced by the people observing them.

“Our research site is special in that the chimpanzees frequently interact with and even enjoy human company, participating in various touchscreen experiments almost daily for food rewards. '' said Dr. Akiho Muramatsu of Kyoto University.

“So we thought there was an opportunity to not only explore potential similarities in effects that are relevant to viewers, but also do it in the context of chimpanzees, which share a unique bond with humans.”

The researchers made this discovery after analyzing thousands of sessions in which chimpanzees completed touchscreen tasks over a six-year period.

The researchers found that across three different number-based tasks, the chimpanzees performed better on the most difficult task as the number of experimenters observing them increased.

In contrast, they also found that on the simplest tasks, chimpanzees performed worse when they were observed by more experimenters and other familiar people.

Scientists note that the specific mechanisms underlying these audience-related effects remain unclear, even in humans.

They suggest that further studies in non-human apes may provide more insight into how this trait evolved and why it developed.

“Our findings suggest that how much humans care about witnesses and audiences may not be so unique to our species,” said Shinya Yamamoto of Kyoto University. said the doctor.

“These characteristics are a core part of how our society is primarily based on reputation, and if chimpanzees also pay special attention to their audience when performing their tasks, then these It stands to reason that audience-based traits may have evolved before reputation-based traits.''Society arose in our great ape lineage. ”

of the team findings Published in a magazine iscience.

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Kristen Lin others. The presence of an audience influences chimpanzees' performance on cognitive tasks. isciencepublished online on November 8, 2024. doi: 10.1016/j.isci.2024.111191

Source: www.sci.news

Chimpanzees Perform Better at Difficult Tasks with an Audience present.

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Chimpanzee taking a number test on a touch screen

Akiho Muramatsu

Audience pressure can affect human performance both positively and negatively, and it turns out the same is true for our closest relatives.

Kristen Lin He and his colleagues at Kyoto University in Japan tested groups of six chimpanzees kept at the university's Primate Research Institute on three numerical tasks of varying difficulty.

In the first task, numbers from 1 to 5 appeared in random positions on the screen, and the chimpanzees simply had to touch the numbers in the correct order to receive a reward.

In the second task, the numbers were not adjacent. For example, 1, 3, 5, 7, 11, 15 might appear on the screen. Again, the chimpanzees had to press a number from the minimum value to the maximum value to receive a reward.

Finally, in the most difficult test, when the first digit in the sequence was pressed, the remaining digits were hidden behind a checkered square on the screen. This meant that the chimps had to memorize the positions of the numbers in order to press them in the correct order.

The chimpanzees were tested on this task thousands of times over six years with a variety of audiences, including one to eight human observers, people familiar with chimpanzees, and people new to chimpanzees.

When the task was easy, the chimpanzees performed worse as more people watched. However, on the most difficult task, all six chimpanzees performed better as the audience size increased.

“It was very surprising that performance improved so much as the number of human experimenters increased, because having more humans present can be distracting,” Lin says. “However, the results suggest that this may actually motivate them to perform even better.

“For the easiest tasks, humans may distract them, but for the most difficult tasks, humans can become a stressor and actually motivate them to perform better.”

team members Shinya YamamotoResearchers from Kyoto University also said they were surprised to find this effect in chimpanzees.

“Such audience effects are thought to be unique to humans who live in reputation-based and normative societies, where it is possible to perform well in front of an audience, and others to perform well in front of an audience. Sometimes they perform worse than they do,” he says. “However, our study shows that this audience effect may have evolved in the ape lineage before this type of normative society developed.”

Yamamoto says it's difficult and sometimes dangerous to tease out direct human implications from non-human research. “However, by telling people that chimpanzees are the same way, it may be possible to subtly calm the nerves of people who are extremely nervous in front of others.”

Miguel Llorente A team of researchers from the University of Girona in Spain suggests that it may be possible to further study how audience effects relate to individual chimpanzee personalities.

“To generalize these results to natural chimpanzee behavior, we will investigate these effects with chimpanzee audiences to more fully understand how these dynamics play out in natural social contexts.” “It would also be interesting to understand that,” he says.

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Source: www.newscientist.com

Chimpanzees communicate with each other at a speed comparable to human conversation

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Chimpanzees in Budongo Forest, Uganda

Catherine Hobaiter

When chimpanzees socialize, they exchange gestures at a rate similar to how humans converse.

The researchers surveyed five wild chimpanzees.Pan troglodytesThe researchers studied 8,559 gestures made by 252 chimpanzees across chimpanzee (Pan troglodytes) communities in East Africa — one of the largest studies of its kind. They recorded face-to-face interactions between the apes, recording the timing of one chimpanzee's gestures relative to those of the other.

An analysis of the ape “conversations” found that chimpanzees' signaling intervals are remarkably similar to human interactions, and even a little faster: “On average, it takes 120 milliseconds between the end of one gesture and the start of the next,” the researchers say. Gal Badig “In humans, the average is about 200 milliseconds, so this is very close,” said researchers at the University of St Andrews in the UK.

All chimpanzee groups responded quickly, but the exact timing varied from group to group: for example, chimpanzees from Sonso, Uganda, took a few milliseconds longer to return the gesture than the other chimpanzee groups studied.

Such differences in timing exist in human languages ​​too. For example, Japanese speakers generally Faster turn changes Japanese people have a different conversational style than Danish speakers. “We don't know exactly why,” says Vadig. “As with humans, we don't know if it's a cultural difference, something we've learned over time, or a reaction to our environment.”

Chimpanzees interacting in the Budongo Forest in Uganda

Adrian Soldati

Only 14 percent of the interactions the researchers observed between chimpanzees involved any kind of interaction. Most consisted of a single gesture, such as “go away” or “follow me,” in which the other person ran away or followed. But interactions were more frequent when the chimpanzees were negotiating over food or grooming.

“What's really exciting about this study is that it shows that communication is a cooperative, socially engaged process in non-human animals,” Budig says, “and that the processes involved in human language may have actually evolved much earlier than we thought.”

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Source: www.newscientist.com

Ill chimpanzees search for different plants with medicinal qualities

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A chimpanzee eating sandpaper nuts in Budongo Forest, Uganda.Fig genus

Elodie Freyman (CC-BY)

Some plants that chimpanzees eat when they are sick or injured have been found to have medicinal properties, providing some of the strongest evidence yet that our close relatives self-medicate.

Although there have been reports for decades of chimpanzees using plants to self-medicate, it's difficult to pinpoint when wild animals get sick and what effect their diet may have.

Elodie Freyman Oxford University researchers tracked wild chimpanzees in Uganda's Budongo Forest, recording when they became ill and what they ate. By analysing feces for signs of intestinal parasites and examining urine samples for elevated levels of immune cells, the researchers identified chimpanzees with obvious wounds or intestinal infections.

An analysis of 53 plant extracts ingested by sick or injured chimpanzees found that 88 percent were effective against bacteria pathogenic to humans, including antibiotic-resistant strains like MRSA, and extracts from all species sampled had anti-inflammatory properties.

This systematic approach has allowed the researchers to identify and characterize more species used by chimpanzees than ever before. Kirsty Graham “It's a very impressive project,” said Robert Cole, a researcher at the University of St. Andrews in the UK who was not involved in the work.

Sick chimpanzees would leave the safety of their group to eat certain plants, often choosing plants that were rarely eaten in that area. The rarity of these events makes self-medicating behavior very difficult to observe, but at the same time, it is one of the strongest pieces of evidence that it is a targeted response to illness.

Chimps are typically hesitant to try unfamiliar foods that might be dangerous, Freiman says, so choosing to eat an unusual plant means they have a special reason to do so: “If they're sick, they're not going to stuff their mouths with things that might make them sicker,” she says.

But this doesn't capture everything that's going on, Graham says, because chimpanzee diets are still very diverse. Over generations, a chimpanzee community may be able to overcome this reluctance to new foods if chimpanzees learn from other animals which plants to eat. Simultaneous direct comparisons of the diets of sick and healthy chimpanzees might reveal whether these are active choices, Graham suggests.

Team Members Fabian Schultz Researchers at the Brandenburg University of Applied Sciences in Germany hope that by identifying active compounds in plant extracts, they might uncover promising drug candidates for humans. “What if we could save human lives by following the example of our animal companions?” he says.

In a report released earlier this year, an orangutan, another great ape, was spotted applying plant leaves directly to a wound in an apparent act of self-medication.

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Source: www.newscientist.com

Chimpanzees can remember and recognize photos of long-lost friends

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Chimpanzees at a zoo were shown photos of old group members to test their memory.

Johns Hopkins University

Bonobos and chimpanzees appear to be able to recognize photos of former group members, even animals they haven’t seen in over 20 years. This means that these apes have the longest social memory of any non-human animal.

Great apes such as gorillas, chimpanzees, and bonobos are known to have impressive memories. For example, some chimpanzees The exact location of a particular fruit tree In the forest, predict what will happen next in a previously seen movie. The researchers also found hints that great apes have long-term memories of individuals.

“When we went back to great ape populations that we had studied in the past, we noticed that they seemed to recognize and remember us,” he says. laura lewis at the University of California, Berkeley.

To investigate how long this social memory lasts in great apes, Lewis and her colleagues tested 12 bonobos and 15 chimpanzees living in zoos in the UK, Japan, and Belgium.

For each animal, the researchers flashed side-by-side photos of two different great apes on a screen for three seconds. One of the photos was of a monkey that had been living with them for at least a year, and the other was of a stranger.

Using eye-tracking technology, the researchers found that all participants looked on average about a quarter of a second longer at images of former group members than at images of strangers. As zookeepers say, former co-workers with whom they had a good relationship stay in the picture even longer.

This finding shows that these apes remember their acquaintances even after long periods of time. “It’s not that different from walking down the street in a big city and unexpectedly running into someone you went to school with and doing a double take,” team members say. Christopher Krupenier at Johns Hopkins University in Maryland.

In the most extreme case, a bonobo called Louise appeared to recognize her sister Loretta and nephew Erin after being separated for more than 26 years.

“This is the longest long-term social memory ever recorded in a non-human animal,” Lewis said.

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Source: www.newscientist.com