Chimpanzees found to age in ways similar to humans

MARCH 31, 2020 REPORT

by Bob Yirka , Phys.org

A team of researchers from the University of New Mexico and the Kibale Chimpanzee Project in Uganda has found similarities between the way chimpanzees and humans age. In their paper published in Proceedings of the National Academy of Sciences, the group describes their 20-year study of chimps living at Kibale National Park and what they learned about the ways they age.

Prior research has shown that as people age, they undergo changes to their hypothalamic-pituitary-adrenal (HPA) axis—a biological system that plays a major role in how people respond to stress. One of those ways is bumping up levels of cortisol production. Cortisol is a hormone that plays a role in regulating metabolism and blood pressure. Prior research has also shown that excess cortisol can lead to problems such as a reduction in clear thinking, a weakened immune system and inflammation—all symptoms of aging in humans. But now, it appears that chimpanzees undergo a similar process.

The work by the team was part of a large overall effort to study physical and behavioral traits of chimpanzees in a near-natural setting. As part of that effort, team members placed plastic bags in the trees where the chimps reside in the park to collect urine samples from 59 adults. The team has been collecting urine samples from the chimps for approximately 20 years. In analyzing its composition, the researchers have found that the chimps also experience elevated levels of cortisol as they grow older—and furthermore, the higher levels of the hormone could not be attributed to reproductive activity or social status. They claim the increased levels of cortisol suggest chimps age similarly to humans.

The researchers found that cortisol levels were highest in the males when they were making moves on sexually receptive females. They also found that cortisol levels were highest in the females when they were sexually receptive—a time when females are under stress from competing males. They also suggest that rising cortisol levels in hominids are an ancient attribute, and are thus not a byproduct of aging.

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Adolescent male chimps still need their mamas

FEBRUARY 18, 2020

by Robin A. Smith, Duke University

Even kids who are nearly grown still need a parental figure to help them navigate the long path to adulthood—and our closest animal relatives are no exception.

A new study of wild chimpanzees finds that males whose moms were present during their tween and teen years had higher odds of survival later in life, compared with their peers who lost their mothers before they finished puberty.

The results appear in the February 2020 issue of the journal Behavioral Ecology and Sociobiology.

Beginning in the 1960s, researchers led by primatologist Jane Goodall started monitoring the wild chimpanzees living in Gombe National Park in western Tanzania, making note of things like births, deaths, who was related to who and how the animals interacted. Using more than 50 years of data for 247 chimpanzees, a team from Franklin & Marshall College, The George Washington University and Duke University examined the impacts of having or losing a mother at different stages of a chimpanzee's growing up.

Perhaps not surprisingly, they found that a mom's continued presence after weaning means better outcomes for her kids. Chimpanzees whose mothers were still around by their tenth birthdays lived longer than their orphaned peers.

But at later stages of growing up, the effect was stronger for sons than daughters. Sons whose mothers were still around between the ages of 10 and 15 were more likely to survive than sons who lost their mothers during that time, whereas daughters did just fine either way.

There's a good reason for mom's diminishing influence on daughters, the researchers say. In Gombe National Park, half of all chimpanzee females leave their birth families behind at puberty. But adolescent males stay put, which means mothers and sons are more likely to form lifelong bonds.

Exactly how a mom's continued presence enhances her adolescent offspring's survival is still unclear, the researchers say.

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Less offspring due to territorial conflicts

JANUARY 3, 2020

by Max Planck Society

Both humans and chimpanzees can be extremely territorial, and territorial disputes between groups can turn violent, with individuals killing each other. In humans, such between-group competition can escalate to war and devastating loss of human life. Researchers from the Max Planck Institute for Evolutionary Anthropology studied wild Western chimpanzees to find out whether territorial behavior may have shaped counter-strategies. One important strategy that is evident in both humans and chimpanzees, but rare in the rest of the animal kingdom, is the capacity to work together in order to achieve a goal, for example to defend a territory—even if it is together with individuals who are not one's kin.

The researchers tested whether the effects of territoriality—the pressure that neighboring groups exert on each other on one side, and the competitive capacity of a group on the other side—impact female reproductive success. Reproductive success is a measure of how many of one's genes pass into the next generation and therefore how much of an influence one's traits have on subsequent generations. Using long-term data on four neighboring chimpanzee communities that span several decades of these animals' lives, the researchers show that between-group competition has negative effects on wild female chimpanzees' reproductive success. Competition between groups seems to have a selective impact and could have helped shape associated traits in this species.

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Chimp champ Jane Goodall enlists advanced mapping technology for nature and humanity

JULY 10, 2019

by Bradley J. Fikes

In groundbreaking research beginning nearly 60 years ago, Jane Goodall has devoted her life to understanding our closest relatives, chimpanzees.

Goodall, 85, lived among chimps in Tanzania's Gombe Stream National Park, gathering observations that reached the public in a series of popular books. She was first scientist to describe chimpanzees as individuals, giving them memorable names such as Flo, Fifi and Flint. She also depicted how chimps live in societies, in peace, conflict and even war.

Now the English primatologist has enlisted a provider of 21st-century mapping science to understand and protect nature, and help their human neighbors thrive alongside wildlife without conflict.

Goodall and Geographic Information System, or GIS, provider Esri announced the partnership Monday at Esri's 2019 user meeting in San Diego.

The Redlands-based company will provide the Jane Goodall Institute GIS software tools to document natural and human resources, including wildlife reserves, towns, and flood control areas. The institute, fellow scientists and local volunteers will collect the information and with Esri's help, use that knowledge to refine their conservation efforts.

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Chimpanzees at the crossroads: Adapt to living outside protected areas

Date:  May 22, 2019

Source:  University of Kent

Research carried out into the impact of changes to chimpanzee habitats found they have adapted to human developments in a number of ways -- including learning how to cross roads safely and the best times to visit human habitats -- but their survival is still threatened.

A team of anthropologists from the University of Kent and universities in Spain, in collaboration with the Tacugama Chimpanzee Sanctuary in Sierra Leone, made their discoveries from hidden cameras during an eight-month study in the African country.

Although chimpanzees living in fragmented habitats cross roads to move from one area to another of their home range and may approach human settlements, any further road widening, tarmacking or expansion and urbanisation could significantly affect their distribution and abundance.

Consequently, the research team suggests care with infrastructure development, as well as developing agreements with farmers to allow strategic fallow areas to regenerate into community-managed forest refuges providing corridors for wildlife and vital natural resources and ecosystem services for both humans and wildlife.

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Captive chimpanzees spontaneously use tools to excavate underground food

MAY 15, 2019

by Public Library of Science

Chimpanzees in captivity can successfully work out how to use tools to excavate underground food, even if they've never been presented with an underground food scenario before, according to a study published May 15, 2019 in the open-access journal PLOS ONE by Alba Motes-Rodrigo and colleagues and directed by Adriana Hernandez-Aguilar from the University of Oslo.

Recent studies have indicated that wild chimpanzees and bearded capuchins are capable of using tools to excavate underground food such as plant roots, corms, and tubers—overturning earlier hypotheses that this type of tool use was unique to humans and their ancient hominin ancestors. In this study, the authors studied tool use and selection in captive chimps to further understand how food excavation behavior may have developed.

Motes-Rodrigo and colleagues monitored a colony of ten chimpanzees (Pan troglogytes) living on an island enclosure at the Kristiansand Zoo in Norway, eight of whom were born in captivity and none of whom had previously performed excavating behaviors. The authors dug five small holes and placed whole fruit in each, initially leaving the holes open to alert the chimpanzees to the fruit, and later filling in each hole. At first, the authors provided ready-made tree stick and bark tools; in a second experiment, they did not provide ready-made tools for excavation.

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A case of the chimp sniffles or major outbreak? Syndromic surveillance may hold the key

MAY 10, 2019

by Morris Animal Foundation

Two sniffling chimps could be one too many for a wild chimpanzee community susceptible to respiratory disease outbreaks, report Morris Animal Foundation-funded researchers at the University of Minnesota. The team's findings were a result of their development of a syndromic surveillance system to noninvasively and preemptively detect a potential outbreak of respiratory disease. The study recently was published in EcoHealth.

"This could significantly improve our ability to intervene and slow down, or even stop, outbreaks among great ape groups," said Dr. Tiffany Wolf, Assistant Professor in the College of Veterinary Medicine, University of Minnesota. "Hopefully, we can use this technique to better understand disease transmission among wildlife around the world."

Respiratory diseases are increasingly recognized as having a significant impact on great ape populations that have at least some level of contact with humans. In Gombe, respiratory disease is responsible for, or has been associated with, more than 50 percent of mortalities in chimpanzees.

Syndromic surveillance is a type of surveillance that can detect a health issue before a disease is diagnosed, or even before a specific pathogen is known to be involved. It uses easily identifiable indicators that do not require physical contact with an individual or a population.

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Bonobos and chimps equally love meat

APRIL 30, 2019

by Jim Barlow, University of Oregon

In an African forest where leopards and poisonous mamba dwell, a University of Oregon team once had to flee charging boar. But it was a brief detour in research that adds to the idea that bonobos are neither hippies nor vegans.

For six months in 2017, the team, including local guides and colleagues from Northern Kentucky University, hiked a 9-square-mile area of the Lomako Forest in the Democratic Republic of the Congo. Their goal was to solidify the idea that bonobos, a female-dominated ape species, eat meat more often than previously believed.

The research effort—funded by the Leakey Foundation and National Geographic Society—paid off.

"Bonobos are a type of chimpanzee, and we are continuing to assess the differences between these different species," said UO doctoral student Colin Brand. "We are finding a lot of similarities and some key differences. Meat-eating seems to be a similar behavior of both species in terms of the rate at which they do it."

Chimps have a broad range in Africa, but bonobos live only in the forest along the big bend of the Congo, the world's ninth-longest river.

While bonobos are known to eat monkeys, some birds and hyrax, their preferred food in the region studied was Weyn's duikers – small antelope easily carried along the ground and up onto tree branches.

In the journal Folia Primatologica, the team documented that bonobos capture and consume meat at the same frequency as male-dominated chimpanzees. They also found that females control the duiker carcasses and get aggressive when other bonobos, especially males, reach for a handout but that they also show tolerance and will share with subadult males.

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Chimpanzees lose their behavioral and cultural diversity

Human impact reduces the behavioral repertoire of chimpanzees

Date:  March 7, 2019

Source:  Max Planck Institute for Evolutionary Anthropology

Chimpanzees exhibit exceptionally high levels of behavioral diversity compared to all other non-human species. This diversity has been documented in a variety of contexts, including the extraction of food resources, communication and thermoregulation. Many of these behaviors are assumed to be socially learned and group-specific, supporting the existence of chimpanzee cultures. As all other great apes, chimpanzees have come under enormous pressure by human activities, leading to a change of the natural environment. Their prime habitat, tropical rainforests and savanna woodlands, are increasingly converted to agricultural farmland, plantations and settlements, or otherwise degraded by the extraction of natural resources and infrastructure development.

Much of the empirical work and resulting debate on the loss of wildlife biodiversity has been conducted in the context of species decline or loss of genetic diversity and ecosystem functions. However, behavioral diversity is also a facet of biodiversity. Due to limited empirical data, until now it had been unclear whether behavioral diversity would similarly be negatively affected by human impact.

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Facial recognition tool tackles illegal chimp trade

By Beth Timmins BBC News

22 January 2019

Wildlife criminals had better watch out! The same software that recognises you in a friend's social media post is being adapted to tackle the illegal trade in chimpanzees.

The amber eyes in the image above belong to Manno, who was trafficked from Africa to Syria before being rescued.

Pictures of Mano are now being used to train the algorithm that could help save members of his endangered species from the same experience. It's a first for chimpanzee conservation.

The algorithm will search through photo posts on social media looking for the faces of rescued apes.

If the technology recognises a trafficked animal, the owners of the accounts featuring the chimp can then be targeted by the authorities.

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Chimpanzees sniff out strangers and family members

October 23, 2018, Max Planck Society

Chemical communication is widely used in the animal kingdom to convey social information. For example, animals use olfactory cues to recognize group or family members, or to choose genetically suitable mates. In contrast to most other mammals, however, primates have traditionally been regarded as "microsmatic—having a poor sense of smell. Although research on olfaction in some primate species has increased in recent years, non-human great apes have been greatly neglected in these studies. Researchers from the University of Leipzig and the Max Planck Institute for Evolutionary Anthropology as well as Durham University have now conducted one of the first studies investigating the signaling function of social odors in non-human great apes. 

The scientists presented two groups of chimpanzees with urine from group members, strangers and an unscented control in aerated plexiglass boxes and videotaped their behavior. Chimpanzees sniffed longer at urine than at the control, suggesting they perceive the odor of other chimpanzees. More importantly, they discriminated between the smell of group members and strangers, sniffing outgroup odors longer than ingroup odors. "Chimpanzees are highly territorial, and encounters between groups are mostly hostile—in fact, they sometimes kill individuals from other communities—so olfactory cues might help them to locate other animals and determine whether they are group members or strangers, enhancing their survival and leading to fitness benefits", says lead author Stefanie Henkel of the University of Leipzig and the Max Planck Institute for Evolutionary Anthropology. "Odor might be especially important because most chimpanzees live in dense forests where visibility is low, and because in chimpanzee societies, group members split up into subgroups that may not see each other for days", Henkel adds. 

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Active participation in group-hunts earns wild chimpanzees meat access

September 10, 2018, Max Planck Society

Wild chimpanzees of the Taï National Park, Ivory Coast, hunt in groups to catch monkeys. By observing group-hunts and meat sharing, an international team of researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, found that chimpanzee hunting behavior is a cooperative act that earns participants a fair share of the prey.

"Chimpanzee hunting success increased when more chimpanzees participated in the hunt or in joint prey searches prior to the start of a hunt", says Liran Samuni of the Max Planck Institute for Evolutionary Anthropology and first author of the study. "The sharing of meat following successful hunts encouraged hunt participation, as prey catchers shared more frequently with hunters than non-hunters, despite similar begging attempts."

Furthermore, the researchers found that chimpanzee hunting behavior was associated with the activation of oxytocin, a neuro-hormone established as a facilitator of cooperative behavior in humans and other animals. Oxytocin activation during chimpanzee hunting is a potential mechanism facilitating cooperative hunting. "Our new study provides strong support for the cooperative nature of hunting behavior in some wild chimpanzees, likely facilitated by neuroendocrine and behavioral mechanisms", says senior author Roman Wittig.

Like with humans, hunting success is likely motivation and performance dependent, with little guarantee that the effort invested in hunting will pay off. A mechanism in which active hunt participants that did not catch the prey are still rewarded with meat, a highly valuable food source, supports future cooperation to potentially increase performance.

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Tough life in the savannah? Chimpanzee foods are mechanically more demanding than previously thought

Date:  August 10, 2018

Source:  Max Planck Institute for Evolutionary Anthropology

Summary:

A study has analyzed the mechanical properties and the isotopic composition of plant foods eaten by chimpanzees living in the tropical rain forest and savannah woodland. They found that the savannah chimpanzees eat foods that are more mechanically challenging and therefore may place higher selective pressures on their chewing apparatus compared to their conspecifics living in the rainforest.

Chimpanzees are generally known as the ripe fruit specialist among the great apes but also incorporate other food items such as leaves and seedpods into their diets. Savannah chimpanzees are thought to rely on these non-fruit resources more than their forest counterparts. The mechanical properties of plant foods can vary substantially but to date there were no comparative data available for chimpanzee populations living in distinct habitat types.

Adam van Casteren of the Max Planck Weizmann Center for Integrative Archaeology and Anthropology at the Max Planck Institute for Evolutionary Anthropology went out to compare the material properties of various plant foods eaten by chimpanzees in a tropical rainforest (Ngogo, Uganda) and a savannah woodland (Issa Valley, Tanzania). Using a portable mechanical tester, he measured the physical properties of plant tissues and found that some plant parts from the mosaic savannah woodland habitat, such as the outer casing of the Strychnos fruit, had much higher toughness and stiffness values than the plant tissues he tested from the rainforest. "I was surprised to see that some values even exceed those recorded for orangutan foods as they are generally considered to consume the most mechanically challenging diet of all the great apes," says van Casteren.

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Monkeys benefit from the nut-cracking abilities of chimpanzees and hogs

Mangabey monkeys get free access to fresh tropical nuts by profiting from the nut-cracking skills of chimpanzees and the strong jaws of hogs

Date:  July 19, 2018

Source:  Max Planck Institute for Evolutionary Anthropology

To investigate the scavenging behaviour first author Bryndan van Pinxteren of the University of Amsterdam analysed all video material from the camera traps by scoring the visiting behaviour of mangabey monkeys, fowl species and squirrels to chimpanzee nut-cracking sites in relation to known nut-cracking events. Furthermore, since mangabeys are infrequently preyed upon by chimpanzees, he investigated whether they perceive an increased predation risk when approaching nut remnants. In total, 190 nut-cracking events were observed in four different areas of Tai National Park, Ivory Coast.

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Chimps Seen Sucking Brains from Monkeys' Heads

By Mindy Weisberger, Senior Writer | April 12, 2018 12:28pm ET

Chimpanzees are primarily plant eaters, though they enthusiastically eat animals when they can catch them, and monkeys are an especially desirable treat. But once the snack is in hand — and with so many delicious body parts to choose from — which do the predatory primates eat first?

Wonder no longer. Scientists have discovered that it all depends on the age of the unfortunate prey.

Researchers recently filmed chimpanzees (Pan troglodytes) in Tanzania's Gombe National Park excitedly munching on monkeys, hoping to learn more about the chimps' carnivorous eating habits. Whenever older monkeys were on the menu, chimps tended to initially harvest the organs — particularly the liver, which is rich in fat, the scientists reported in a new study.

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How infighting turns toxic for chimpanzees

March 26, 2018 by Robin A. Smith, Duke University

Power. Ambition. Jealousy. According to a new study, the same things that fuel deadly clashes in humans can also tear apart chimpanzees, our closest animal relatives.

In the early 1970s, primatologist Jane Goodall and colleagues studying chimpanzees in Gombe National Park, Tanzania, watched as a once-unified chimp community disintegrated into two rival factions. What followed was a period of killings and land grabs, the only civil war ever observed in wild chimpanzees.

Now, thanks to newly digitized field notes in the Jane Goodall Institute Research Center at Duke University, scientists have been able to take a closer look at the seeds of the conflict. What started as infighting among a few top males vying for status and mates is likely what eventually caused the whole group to splinter.

The study was published March 22 in the American Journal of Physical Anthropology.

The exact nature and cause of the split leading to what Goodall called the "Four-Year War" at Gombe from 1974 to 1978 has long been a mystery, said first author Joseph Feldblum, postdoctoral associate with professor Anne Pusey at Duke. During the war, males within an area of the park known as Kasekela teamed up to raid neighboring territories, brutally beating and killing half a dozen former comrades.

Some researchers have suggested the friction was sparked by the banana feeding station Goodall used to lure chimpanzees for observation. They proposed that two distinct chimp communities may have existed all along or were already dissolving when Goodall began her research, and the feeding station merely brought them together in a temporary truce until they parted again. But new results from a team at Duke and Arizona State University suggest something more was going on.

Using data extracted from Goodall's copious hand-written notes and checksheets, which Pusey has spent the last 25 years archiving and digitizing, the researchers analyzed the shifting alliances among 19 male chimpanzees leading up to the split.

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Bonobo and chimpanzee gestures share multiple meanings

Date:  February 27, 2018

Source:  University of York

Summary:

Two closely related great ape species, the bonobo and chimpanzee, use gestures that share the same meaning researchers have found.

Chimpanzees and bonobos use gestures in a variety of different situations and for multiple purposes, such as to initiate and change positions during grooming.

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Chimpanzee deaths in Uganda pinned on human cold virus

Date:  December 13, 2017

Source:  University of Wisconsin-Madison

Summary:

In the wild, chimpanzees face any number of dire threats, ranging from poachers to predators to deforestation. That’s why scientists, investigating an outbreak of respiratory disease in a community of wild chimpanzees in Uganda’s Kibale National Park, were surprised and dismayed to discover that a human “common cold” virus known as rhinovirus C was killing healthy chimps.

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Chimps make an extra effort to warn their oblivious friends when deadly snakes are nearby - via Herp Digest

by Alessandra Potenza Nov 15, 2017, Verge

                 

A chimp in Uganda’s Budongo Forest sees the fake snake. Video: Taï Chimpanzee Project

Chimpanzees live in dense forests filled with poisonous snakes and other threats — but luckily, they’ve got each other’s backs.

New research shows that when chimpanzees see a poisonous snake, they make an extra effort to alert other chimps that are unaware of the danger by making alarm calls and pointing out the location of the snake by gazing at it. That suggests that chimps communicate — and cooperate — with each other in more complex ways than previously thought possible.

Previous studies have shown that chimps warn others of danger, and are more likely to stop making alarm calls after the other chimps have climbed to safety. But today’s study, published in Science Advances, goes an extra step: it shows that chimps change their behavior — and adapt their alarm calls — based on whether the other chimps are aware of the danger. In other words, chimps take other animals’ perspective into account when communicating. And that’s pretty much what people do: when we talk, we consider what information is available to others.

“There seems to be more going on in chimpanzee communication — and possibly in other animal communication, especially the vocalization part — than has been assumed possible before,” says study co-author Catherine Crockford, a researcher at the Max Planck Institute for Evolutionary Anthropology.

Crockford got the idea for her research while spending hours in Uganda’s Budongo Forest, and observing chimps alerting each other of poisonous snakes. First, she and her team created fake snakes out of chicken wire and plaster that resembled deadly gaboon and rhinoceros vipers. “They were convincing enough to scare our field assistants,” she says. The researchers then placed the fake snakes where chimpanzees were expected to pass by, setting up a video camera to record their reactions. One-third of the animals were observed alarm calling other chimps in their group; then they indicated the snake’s position by gazing back and forth from the snake to the other chimps, continuing to do this until the others had seen the snake.

In a second experiment, the researchers also played prerecorded calls — either an alarm hoo or a rest hoo. The two calls influenced how the chimps reacted: those that had heard the rest call a few seconds before coming across the fake snake — which suggested that a nearby group member was unaware of the snake — gave more warnings, making more alarm calls and using body language. The findings suggest that when a chimp thinks its fellows don’t know about the danger, the chimp will make an extra effort to make sure they’re informed. In other words, its vocalizations seem to change based on what the other chimps know or don’t know.

The findings add to our understanding of how animals communicate with each other. They also tell us a bit about human evolution: it suggests that relatively complex forms of communication may have emerged before humans developed a language. “I think it helps us learn much more about ourselves, how our brains work,” Crockford says. And perhaps even more about how we interact with each other.

The chimps in the study were found to give more warnings about the snake if the other chimps were friends or kins. “They really have these strong friendships,” Crockford says. These friendships help individuals thrive: chimps and other primates who are more socially connected are found to have more offspring, Crockford says. “The motivation to keep friends [safe], to stop them being taken away by others, probably occupies quite a lot of their day and their brain work,” she says. “It’s a really crucial part of survival.”

What grosses out a chimpanzee? The origins of disgust

Origins of disgust

Date:  November 17, 2017

Source:  Kyoto University

Chimps show increased latencies to feed, and tendencies to maintain greater distances from possible contaminants and/or outright refusals to consume food in test conditions, hinting at the origins of disgust in humans.

Chimpanzees do some pretty disgusting things.

In their natural habitats, chimpanzees are known to pick up seeds from feces and re-ingest them. In captivity, some practice coprophagy: the deliberate ingestion of feces. These behaviors usually involve their own fecal matter, or that of their closest family members. If presented with feces and other bodily fluids from others, however, that's an entirely different story.

In 2015, researchers from Kyoto University's Primate Research Institute went to the Primate Center at the 'Centre International de Recherches Médicales de Franceville' (CIRMF) in Gabon to test whether chimpanzees are grossed out by some of the same things as humans, particularly those that are sources of infectious disease.

Avoiding biological contaminants is a well-known manifestation of the adaptive system of disgust. In theory, animals evolved with this system to protect themselves from pathogens and parasites, which are often associated with media or substrates that invoke our sense of disgust. For example, bodily products are universal disgust elicitors in humans, but until now we did not know whether they also elicit similar reactions in our primate cousins.

In a new study published in Royal Society Open Science, researchers found evidence that exposure to biological contaminants -- ie feces, blood, semen -- via vision, smell, and touch, influences feeding choices even in chimpanzees.

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