Chimps sometimes care for others' wounds, and scientists want to know why
But as she flipped through a field book at the site containing the observations of researchers dating back to 1993, she began to notice accounts of the chimps not just ingesting plants to self-medicate, but using them for wound care — and sometimes not always on themselves.
In looking through 30 years of observations — as well as eight months of their own — Freymann and her colleagues found that the chimpanzees of Budongo have, in dozens of instances, administered first aid on themselves and others. According to Freymann, these observations, published Wednesday in Frontiers in Ecology and Evolution, raise questions over chimpanzees' capacity for empathy and altruism.
'It's hard to prove that a nonhuman animal has empathy because you can't sit down and have a conversation with them,' Freymann said. 'Most studies have been done in captivity. But this provides a case study, or several case studies, of chimpanzees in the wild possessing the ability to not just take care of themselves, but to transfer those skills to others.'
Chimpanzees and their behaviors have long dominated the field of zoopharmacognosy, the study of nonhuman self-medication. In addition to Freymann's previous research looking into chimpanzees ingesting healing plants to self-medicate, researchers who documented chimpanzees using insects to treat themselves and others in Loango National Park in Gabon argued that their behavior was evidence of their capacity for 'prosocial behaviors,' or voluntary actions that serve the best interest of another.
The research into the chimpanzees of Budongo found 34 instances of the chimpanzees practicing self-care, whether it be something as simple as licking their wounds or using leaves to wipe after a bowel movement or mating, to something more complex, such as chewing up plants and putting the material on a wound. There have been seven more instances of chimpanzees providing this sort of care on other chimpanzees and not just related kin.
In 2012, a subadult male — a chimpanzee between the age of 10 and 14 — identified as PS sucked the wound on the leg of another subadult male identified as ZG. In 2008, researchers documented an adult male identified as NK removing the nylon snare off an unrelated adult female.
The behavior also raises questions over whether the animals' caring skills are instinctual or acquired and then passed on through social learning, Freymann said. In 2008, researchers observed an adult female identified as NB, injured in a bout of intragroup aggression, applying a folded and chewed leaf to her wound. Her daughter, a juvenile female identified as NT, observed her mother doing this and then mimicked the behavior, chewing a leaf and then applying it to her mother's wound.
'I'm not making a case that every certain medicinal behavior is learned, but I think it's not out of the question that chimpanzees are capable of possessing medicinal culture,' she said.
Given that apes are considered the closest evolutionary cousin to human beings, understanding 'cognitive and social foundations of health-care behaviors in humans requires examining their evolutionary precursors in our closest living relatives,' Freymann argued in her research article. The chimpanzee behavior observed in Budongo suggests that 'the shared ancestors that we have with chimps and apes would have likely been capable of this kind of caregiving and have the capacity to identify those in need of care and to provide that to others,' Freymann said.
But Alexander Piel, a University College London associate professor of evolutionary anthropology who was not involved in Freymann's research, noted that the prosocial behavior demonstrated by chimpanzees in Budongo was very rare, which makes him reluctant to tie the findings to human evolution. There's always an inclination, he said, to connect similarities between humans and apes to evolution, and while it's always a possibility, 'we share other features with them, like our intense sociality, and we share them with non-apes.'
Researchers have observed prosocial health-care behaviors among non-ape species such as elephants and dwarf mongooses, Freymann wrote in her study. 'The fact that we see them in non-closely related species suggests that there are some other drivers to this beyond humanness or human-relatedness. … Empathy is a part of the equation, but the data doesn't support that it's the ultimate driver of this behavior,' Piel said.
The findings provide a good jumping-off point, Piel said, for exploration into the drivers behind this rare type of prosocial behavior — for example, why chimps are so selective in providing health care to other chimps. Freymann said there will be more studies to come, as well as more long-term monitoring.
'I think we're going to find medicinal cultures not just in chimps but in other animals as well,' Freymann said. 'There's debate always, but there are some medicinal behaviors that appear to be instinctual, the more basic ones. There are some behaviors that we've observed that I think are too complex to be instinctual.'
Hashtags
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
Yahoo
2 hours ago
- Yahoo
Fossils show two types of ancient human ancestors lived at the same place and time. One was possibly an unknown species
Ancient, fossilized teeth, uncovered during a decades-long archaeology project in northeastern Ethiopia, indicate that two different kinds of hominins, or human ancestors, lived in the same place between 2.6 million and 2.8 million years ago — and one of them may be a previously unknown species. The discovery provides a new glimpse into the complex web of human evolution. Ten of the teeth, found between 2018 and 2020, belong to the genus Australopithecus, an ancient human relative. Meanwhile, three teeth, found in 2015, belong to the genus Homo, which includes modern humans, or Homo sapiens. The results were published Wednesday in the journal Nature. Such an overlapping of two hominins in the fossil record is rare, which had previously led scientists to believe that Homo appeared after Australopithecus, rather than the two being contemporaries. Australopithecus species walked upright much like modern humans, but had relatively small brains, closer in size to those of apes. The emergence of Homo species, with their larger brains, is easy for people today to view as some sort of evolutionary upgrade on a path to modern humanity. But the coexistence of the two demonstrates that hominins developed, and lived, in multiple varieties at once. 'This new research shows that the image many of us have in our minds of an ape to a Neanderthal to a modern human is not correct — evolution doesn't work like that,' said study coauthor Kaye Reed, research scientist and president's professor emerita at the Institute of Human Origins and emeritus professor at the School of Human Evolution and Social Change at Arizona State University, via email. 'Here we have two hominin species that are together. And human evolution is not linear, it's a bushy tree, there are life forms that go extinct.' Since 2002, Reed has been a codirector of the Ledi-Geraru Research Project, which is focused, in part, on searching for evidence of early Homo species. In 2015, the team announced the discovery of the oldest known Homo jawbone at 2.8 million years old. It has also searched for later evidence of Australopithecus afarensis, which first appeared 3.9 million years ago, but there is no sign of these ancient human relatives in the fossil record after 2.95 million years ago — suggesting they went extinct before Homo's first appearance. Australopithecus afarensis is best represented by the famed fossilized remains of Lucy, discovered in 1974 in Ethiopia. Lucy was shorter than an average human, reaching about 3.3 feet (1 meter) in height, had an apelike face and a brain about one-third the size of a human brain. Her fossil showcased a mixture of humanlike and apelike traits and provided proof that ancient human relatives walked upright 3.2 million years ago. When the team discovered the Australopithecus teeth during two separate digs in 2018 and 2020, it compared them with species such as afarensis and another hominin group known as garhi, but they didn't match up. Instead, the scientists believe the teeth belong to a previously unknown species of Australopithecus that walked the Earth after Lucy — and alongside an early Homo species. 'Once we found Homo, I thought that was all we would find, and then one day on survey, we found the Australopithecus teeth,' Reed said. 'What is most important, is that it shows again, that human evolution is not linear. There were species that went extinct; some were better adapted than others, and others interbred with us — we know this for Neanderthals for sure. So anytime that we have another piece to the puzzle of where we came from, it is important.' Cracks in Earth's surface The teeth were found in Ethiopia's Afar region, a key place for researchers seeking answers about human evolution. A variety of preserved fossils have been found there as well as some of the earliest stone tools, Reed said. The Afar region is an active rifting environment — the tectonic plates beneath its earth are actively pulling apart and exposing older layers of sediment that shed light on almost 5 million years of evolution, Reed said. 'The continent is quite literally unzipping there, which creates a lot of volcanism and tectonics,' said study coauthor Christopher Campisano, associate director and associate professor at the Institute of Human Origins and associate professor at the School of Human Evolution and Social Change at Arizona State, in a video the school released. 'At 2 1⁄2, 3 million years ago, these volcanoes spewed out ash that contain crystals called feldspars that allow us to date the eruptions that were happening on the landscape when they're deposited.' The Australopithecus teeth documented in the new study were dated to 2.63 million years ago, while the Homo teeth are from 2.59 million and 2.78 million years ago. But the team is cautious about identifying a species for any of the teeth until it has more data and more fossils. 'We know what the teeth and mandible of the earliest Homo look like, but that's it,' said Brian Villmoare, lead study author and associate professor in the department of anthropology at the University of Nevada, Las Vegas, in a statement. 'This emphasizes the critical importance of finding additional fossils to understand the differences between Australopithecus and Homo, and potentially how they were able to overlap in the fossil record at the same location.' The Australopithecus teeth broadly resembled those of the afarensis species in contour and the size of the molars, but features of the cusps and canine teeth had not been previously seen in afarensis or garhi teeth, Villmoare said. The teeth were also different in shape than those of any Homo species, or of the ancient human relative Paranthropus, known for its large teeth and chewing muscles. 'Obviously these are only teeth,' Villmoare said, 'but we are continuing field work in the hopes of recovering other parts of the anatomy that might increase resolution on the taxonomy.' Even just finding the teeth was a complicated task, according to Campisano. 'You're looking at little teeth, quite literally, individual teeth that look just like a lot of other of the little pebbles spread on the landscape,' he said in the video. 'And so, we have a great team of local Afars that are excellent fossil hunters. They've seen these things their entire lives walking around the landscape.' A blip for evolution The new study is important because it provides insight into a time frame from 3 million to 2 million years ago, a mysterious period in human evolutionary studies, said Dr. Stephanie Melillo, paleoanthropologist and assistant professor at Mercyhurst University in Pennsylvania. Melillo was not involved in this research, but she has participated in the Woranso-Mille Paleontological Research Project in the Afar Triangle of Ethiopia. Part of the problem in learning about this stretch of prehistory is how ancient layers of dirt were deposited over the course of history in eastern Africa. 'Erosion in rivers and lakes were at a low level and only a little bit of dirt was deposited in the Afar,' Melillo wrote in an email. 'That deposited dirt contains the fossils — of our ancestors and all the animals that lived with us. When there is little deposition, there are few fossils.' A key feature helping archaeologists to understand humanity's evolution are structural basins, or 'bowls' on Earth's surface that naturally collect layers of sediment better than the surrounding landscape does — like the Turkana Basin stretching across southern Ethiopia and northern Kenya, Melillo said. Previous research has found evidence to suggest that Homo and Paranthropus coexisted there 1.5 million years ago. The new study focuses on the Afar Depression, a basin to the north of the Turkana. 'This contribution by Villmoare and colleagues demonstrates that in the Afar there was also some other species around with Homo — but it isn't Paranthropus,' Melillo said. 'Instead, they identify this 'non-Homo' genus as Australopithecus. They do a very convincing job of demonstrating why the new fossils are not Paranthropus.' The study adds to growing evidence that Australopithecus was not roaming the Afar Depression alone, she said. A mysterious coexistence When Australopithecus and Homo were alive, the Afar Region, now mostly a semidesert, had much more seasonal variation in rainfall than it does today, Reed said. Millions of years ago, the environment there was still dominated by a dry season, but it was interrupted by a brief wet season. Rivers that carried water across the landscape existed for only part of the year. Few trees grew near the river, and the environment nearby was largely wetlands and grasslands. 'We have a fossil giraffe species that was eating grass, which probably indicates they were stressed as they eat trees and bushes almost every place else,' Reed said. 'Were the hominins eating the same thing? We are trying to find out by examining isotopes in their teeth and microscopic scratches on their teeth.' Understanding whether or not Homo and Australopithecus had the same food sources could paint a portrait of how our ancient ancestors shared or competed for resources, Reed said. The team also wants to try to identify which hominin made the stone tools found at the site. At the moment it's impossible to tell exactly how the two hominins coexisted, but Reed said she is hoping that future findings will provide more answers. 'Whenever you have an exciting discovery, if you're a paleontologist, you always know that you need more information,' Reed said. 'You need more fossils. More fossils will help us tell the story of what happened to our ancestors a long time ago — but because we're the survivors we know that it happened to us.' Sign up for CNN's Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.
Yahoo
2 hours ago
- Yahoo
The Reason Why Everyone's Confused About UPFs – and What the Current Science Actually Says
The term 'ultra-processed food' (or UPF, for short) has launched into the nutritional spotlight in recent years, with study after study linking the food group to obesity, heart disease, type 2 diabetes, and a multitude of other chronic conditions. And in the UK, we eat a lot of ultra-processed foods. A recent landmark study showed that UPFs made up a whopping 53% of people's energy intake in the UK, coming second only to the US, where UPFs comprised 55%. This trend has led some researchers to claim that ultra-processed foods are 'a primary causal driver of the obesity pandemic'. But is the study of ultra-processed food actually a genuine scientific breakthrough in understanding diet and disease? Or is it just a fancy new label for foods we already knew were unhealthy? What we know now is there's a lack of a clear definition for ultra-processed foods – and we could sure use one. What Are Ultra-processed Foods? The definition of ultra-processed foods has shifted a bit since the term was first coined by Brazilian researchers in 2009, but now the term basically involves a food product meeting two specific criteria. The first is that the main components of the food are a result of multiple stages of industrial processing. Examples: white sugar, white flour, vegetable oil. The second is that the food has additives not commonly used in at-home cooking. This includes preservatives like BHT, emulsifiers like soy lecithin, stabilising agents like modified corn starch, food dyes, thickening agents, and the ever mysterious 'artificial flavours'. That's a tough definition for the average person to remember, understand, and apply to their food choices. Research actually bears this out. Even people who claim to know what ultra-processed foods are often misidentify which foods are actually ultra-processed. To make things even more confusing, some foods fall into an ultra-processed grey area. Let's take bacon, for example. While bacon certainly has additives thanks to its preservatives, whether it undergoes multiple stages of industrial processing is more nebulous. As a result, bacon has been classified as ultra-processed in some scientific papers, but not ultra-processed in others. Whole-grain bread, certain aged cheeses, and tomato sauce – healthy by most definitions – have also been slapped with an ultra-processed label, only adding to consumer confusion. The (New) Science for Ultra-processed Foods Not only is the definition of ultra-processing a bit fuzzy, there's also some debate as to why ultra-processed foods promote worse health outcomes in the first place. Because not all ultra-processed foods are harmful (see whole-grain bread and tomato sauce, but also yoghurt and dark chocolate), researchers have tried to explain why only some foods categorised as ultra-processed are linked to disease. One hypothesis is that (of all things) eating speed is a central factor. Due to their processing, ultra-processed foods are often softer and easier to chew (think peanut butter vs. peanuts), which makes people eat them faster. Rapid consumption may outpace the brain's ability to signal fullness, causing people to overeat, which may eventually lead to obesity and its associated diseases. But this is only a guess. The science that has been done on eating speed as a major factor in overeating tends to be underwhelming. Another hypothesis is that food additives are the key. Some research suggests that emulsifiers commonly found in UPFs (including polysorbate 80 and carboxymethylcellulose) might harm gut health and set off a cascade of inflammation leading to disease, or that taste enhancers, like MSG and added flavours, might override satiety signals and promote overeating. But the existing evidence for these claims is weak. Plus, given that there are hundreds (if not thousands) of food additives in use, studying the long-term effects of individual additives is challenging. But here's another take: The problem with ultra-processed foods might not be due to ultra-processing at all. The (Old) Science Behind Ultra-processing and Health Before ultra-processed food was ever a buzzword, research had established that certain processed foods were low in beneficial nutrients (fibre, potassium) and high in other not-so-great-for-you things like saturated fat, sugar, and salt. This nutritional imbalance alone could explain why ultra-processed foods are dangerous for our health – with no need to bring processing into the discussion. In fact, when studies have actually analysed ultra-processed foods separately, the biggest offenders for health tend to be soda, processed meat products like hot dogs, take-out style foods like pizza and french fries, and refined grains. These are foods that most dietary guidelines and health professionals have long recommend limiting. Given this, perhaps avoiding ultra-processed foods is just a modern repackaging of the same dietary advice we've heard a million times before. So where does that leave us now –and for the future? The Path Forward for Ultra-processed Food There's a real concern over the lack of clear definition for 'ultra-processed foods'. We've seen it before with health buzzwords like 'healthy', 'all-natural', and 'plant-based'. If ultra-processed food means many different things, does it mean anything at all? After decades of fixating on individual nutrients – from fat and cholesterol to carbohydrates and gluten – it's certainly refreshing that the discussion around ultra-processed foods is a more top-down approach to figuring out what makes us sick. But it's far from perfect right now. You Might Also Like The 23 Best Foods to Build Muscle 10 of the Best Waterproof Boots to Buy in 2019 6 Ways to Improve Your Mental Health
New York Times
5 hours ago
- New York Times
Why Do Screens Keep You Up? It May Not Be the Blue Light.
Experts have long warned about the dangers of blue light before bed. When exposed via smartphones, TVs, laptops and other devices, our brains suppress the production of the hormone melatonin, which normally makes you feel drowsy. As a result, you feel more alert, making it harder to fall — and stay — asleep. But the link between blue light and sleep is murkier than we thought, said Lauren E. Hartstein, an assistant professor of psychiatry at the University of Arizona. She and other researchers have been taking a closer look at the evidence, which suggests that blue light alone may not be causing poor sleep. And in some cases, screen use could even help you drift off. Here's what studies on blue light actually suggest — and what may help you sleep more soundly. Research on blue light and sleep is mixed. Many of the available studies on blue light and sleep are old and are limited by their small sample sizes. They were also often performed in carefully controlled laboratories, so their results don't always reflect real life, Dr. Hartstein said. While it's true that blue light exposure can sink melatonin levels, the limited evidence we have suggests that screen use does not always cause this dip, said Mariana Figueiro, a scientist at the Icahn School of Medicine at Mount Sinai in New York City who studies how light influences health. Some of Dr. Figueiro's research suggests, for instance, that how long you use your device for, how close it is to your eyes and how bright it is may play a role. One of her studies from 2013 found that using an iPad at full brightness for two hours caused melatonin levels to drop slightly, whereas using it for one hour caused no change. Another study from 2014 concluded that watching television from nine feet away had no effect on melatonin levels. And using an iPad at a higher brightness level may suppress melatonin more than using it at a lower brightness level, according to a 2018 study. What you do during the day may also influence screen-related melatonin drops at night. The more bright sunlight you're exposed to during the day, some research suggests, the less susceptible you may be to an evening dip. Want all of The Times? Subscribe.
