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African elephants address one another with name-like calls − similar to humans

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theconversation.com – Mickey Pardo, Postdoctoral Fellow in Fish, Wildlife and Conservation Biology, Colorado State University – 2024-06-11 12:47:10

Elephants have close social bonds, which may have led to the evolution of name-like calls.
Michael Pardo

Mickey Pardo, Colorado State University

What’s in a name? People use unique names to address each other, but we’re one of only a handful of animal species known to do that, including bottlenose dolphins. Finding more animals with names and investigating how they use them can improve scientists’ understanding of both other animals and ourselves.

As elephant researchers who have observed free-ranging elephants for years, my colleagues and I get to know wild elephants as individuals, and we make up names for them that help us remember who is who. The elephants in question live fully in the wild and are, of course, unaware of the epithets we apply to them.

But in a new study published in Nature Ecology and Evolution, we found evidence that elephants have their own names that they use to address each other. This research places elephants among the very small number of species known to address one another in this way, and it has implications for scientists’ understanding of animal intelligence and the evolutionary origins of language.

Finding evidence for name-like calls

My colleagues and I had long suspected that elephants might be able to address one another with name-like calls, but no researchers had tested that idea. To explore this question, we followed elephants across the Kenyan savanna, recording their vocalizations and noting, whenever possible, who made each call and whom the call was addressed to.

When most people think of elephant calls, they imagine loud trumpets. But really, most elephant calls are deep, thrumming sounds known as rumbles that are partially below the range of human hearing. We thought that if elephants have names, they most likely say them in rumbles, so we focused on these calls in our analysis.

Elephant rumbles have a deep, sonorous sound.
Michael Pardo236 KB (download)

We reasoned that if rumbles contain something like a name, then we should be able to identify whom a call is intended for based purely on the call’s properties. To determine whether this was the case, we trained a machine learning model to identify the recipient of each call.

We fed the model a series of numbers describing the sound properties of each call and told it which elephant each call was addressed to. Based on this information, the model tried to learn patterns in the calls associated with the identity of the recipient. Then, we asked the model to predict the recipient for a separate sample of calls. We used a total of 437 calls from 99 individual callers to train the model.

Part of the reason we needed to use machine learning for this analysis is because rumbles convey multiple messages at once, including the identity, age and sex of the caller, emotional state and behavioral context. Names are likely only one small component within these calls. A computer algorithm is often better than the human ear at detecting such complex and subtle patterns.

We didn’t expect elephants to use names in every call, but we had no way of knowing ahead of time which calls might contain a name. So, we included all the rumbles where we thought they might use names at least some of the time in this analysis.

The model successfully identified the recipient for 27.5% of these calls – significantly better than what it would have achieved by randomly guessing. This result indicated that some rumbles contained information that allowed the model to identify the intended recipient of the call.

But this result alone wasn’t enough evidence to conclude that the rumbles contained names. For example, the model might have picked up on the unique voice patterns of the caller and guessed who the recipient was based on whom the caller tended to address the most.

In our next analysis, we found that calls from the same caller to the same recipient were significantly more similar, on average, than calls from the same caller to different recipients. This meant that the calls really were specific to individual recipients, like a name.

Next, we wanted to determine whether elephants could perceive and respond to their names. To figure that out, we played 17 elephants a recording of a call that was originally addressed to them that we assumed contained their name. Then, on a separate day, we played them a recording of the same caller addressing someone else.

YouTube video
We played calls to the elephants in our sample, and some elephants called back.

The elephants vocalized and approached the source of the sound more readily when the call was one originally addressed to them. On average, they approached the speaker 128 seconds sooner, vocalized 87 seconds sooner and produced 2.3 times more vocalizations in response to a call that was intended for them. That result told us that elephants can determine whether a call was meant for them just by hearing the call out of context.

Names without imitation

Elephants are not the only animals with name-like calls. Bottlenose dolphins and some parrots address other individuals by imitating the signature call of the addressee, which is a unique “call sign” that dolphins and parrots usually use to announce their own identity.

This system of naming via imitation is a little different from the way names and other words typically work in human language. While we do occasionally name things by imitating the sounds that they make, such as “cuckoo” and “zipper,” most of our words are arbitrary. They have no inherent acoustic connection to the thing they refer to.

Arbitrary words are part of what allows us to talk about such a wide range of topics, including objects and ideas that don’t make any sound.

Intriguingly, we found that elephant calls addressed to a particular recipient were no more similar to the recipient’s calls than to the calls of other individuals. This finding suggested that like humans, but unlike other animals, elephants may address one another without just imitating the addressee’s calls.

Two elephants, and adult and a juvenile, stand together on a desert.
Elephants’ use of name-like calls underscores their intelligence.
Michael Pardo

What’s next

We’re still not sure exactly where the elephant names are located within a call or how to tease them apart from all of the other information conveyed in a rumble.

Next, we want to figure out how to isolate the names for specific individuals. Achieving that will allow us to address a range of other questions, such as whether different callers use the same name to address the same recipient, how elephants acquire their names, and even whether they ever talk about others in their absence.

Name-like calls in elephants could potentially tell researchers something about how human language evolved.

Most mammals, including our closest primate relatives, produce only a fixed set of vocalizations that are essentially preprogrammed into their brain at birth. But language depends on being able to learn new words.

So, before our ancestors could develop a full-fledged language, they needed to evolve the ability to learn new vocalizations. Dolphins, parrots and elephants have all independently evolved this capacity, and they all use it to address one another by name.

Maybe our ancestors originally evolved the ability to learn new vocalizations in order to learn names for each other, and then later co-opted this ability to learn a wider range of words.

Our findings also underscore how incredibly complex elephants are. Using arbitrary sounds to name other individuals implies a capacity for abstract thought, as it involves using sound as a symbol to represent another elephant.

The fact that elephants need to name each other in the first place highlights the importance of their many, distinct social bonds.

Learning about the elephant mind and its similarities to ours may also increase humans’ appreciation for elephants at a time when conflict with humans is one of the biggest threats to wild elephant survival.The Conversation

Mickey Pardo, Postdoctoral Fellow in Fish, Wildlife and Conservation Biology, Colorado State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Chronic kidney disease often goes undiagnosed, but early detection can prevent severe outcomes

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theconversation.com – Eleanor Rivera, Assistant Professor of Population Health Nursing Science, University of Illinois Chicago – 2025-03-28 07:50:00

Testing for kidney function can help identify chronic kidney disease early enough to intervene.
PIXOLOGICSTUDIO/Science Photo Library via Getty Images

Eleanor Rivera, University of Illinois Chicago

For a disease afflicting 35.5 million people in the U.S., chronic kidney disease flies under the radar. Only half the people who have it are formally diagnosed.

The consequences of advanced chronic kidney disease are severe. When these essential organs can no longer do their job of filtering waste products from the blood, patients need intensive medical interventions that gravely diminish their quality of life.

As an assistant professor of nursing and an expert in population health, I study strategies for improving patients’ awareness of chronic kidney disease. My research shows that patients with early-stage chronic kidney disease are not getting timely information from their health care providers about how to prevent the condition from worsening.

Here’s what you need to know to keep your kidneys healthy:

What do your kidneys do, and what happens when they fail?

Kidneys have multiple functions, but their most critical and unglamorous job is filtering waste out of the body. When your kidneys are working well, they get rid of everyday by-products from your normal metabolism by creating urine. They also help keep your blood pressure stable, your electrolytes balanced and your red blood cell production pumping.

The kidneys work hard around the clock. Over time, they can become damaged by acute experiences like severe dehydration, or acquire chronic damage from years of high blood pressure or high blood sugar. Sustained damage leads to chronically impaired kidney function, which can eventually progress to kidney failure.

Kidneys that have failed stop producing urine, which prevents the body from eliminating fluids. This causes electrolytes like potassium and phosphate to build up to dangerous levels. The only effective treatments are to replace the work of the kidney with a procedure called dialysis or to receive a kidney transplant.

Kidney transplants are the gold standard treatment, and most patients can be eligible to receive them. But unless they have a willing donor, they can spend an average of five years waiting for an available kidney.

Most patients with kidney failure receive dialysis, which artificially replicates the kidneys’ job of filtering waste and removing fluid from the body. Dialysis treatment is extremely burdensome. Patients usually have to undergo the procedure multiple times per week, with each session taking several hours. And it comes with a major risk of death, disability and serious complications.

A dialysis machine at work, with lines into a patient's arm
If your kidneys aren’t working, dialysis can do their job for them.
Picsfive via Getty Images

What are the risk factors of chronic kidney disease?

In the U.S., the biggest contributors to developing chronic kidney disease are high blood pressure and diabetes. Up to 40% of people with diabetes and as many as 30% of people with high blood pressure develop chronic kidney disease.

The problem is, as with high blood pressure, people with early-stage chronic kidney disease almost never experience symptoms. Clinicians can test a patient’s overall kidney function using a measure called the estimated glomerular filtration rate. Current guidelines recommend that everyone – particularly people with risk factors like high blood pressure and diabetes – get their kidney function routinely tested to ensure the condition doesn’t progress silently.

Early treatment for kidney disease often relies on managing high blood pressure and diabetes. New medications called SGLT2 inhibitors, originally developed to treat diabetes, may be able to directly protect the kidneys themselves, even in people who don’t have diabetes.

Patients with early-stage kidney disease can benefit from knowing their kidney function scores and from treatment innovations like SGLT2 inhibitors, but only if they are successfully diagnosed and can discuss treatment options during routine visits with their health care providers.

What are some barriers to early treatment?

Early treatment for chronic kidney disease often gets overlooked during routine clinical care. In fact, as many as one-third of patients with kidney failure have no record of health care treatment for their kidneys in the early stages of their disease.

Even if a diagnosis for chronic kidney disease is noted in a patient’s medical record, their provider might not discuss it with them: As few as 10% of people with the disease are aware that they have it.

That’s partly due to the constraints of the U.S. health care system. The diagnosis, treatment and monitoring of early-stage chronic kidney disease occurs mostly in the primary care setting. However, primary care visit time is limited by insurance company reimbursement policies. Especially with patients who have multiple health problems, doctors may prioritize more noticeably pressing concerns.

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Chronic kidney disease can progress silently over many years.

The result is that many clinicians put off addressing chronic kidney disease until symptoms emerge or test results worsen, often leaving early-stage patients undiagnosed and poorly informed about the disease. Research shows that people who are nonwhite, female and of lower socioeconomic status or education level are most likely to fall into this gap.

But patients are eager for this knowledge, according to a study I co-authored. I interviewed patients who had early-stage kidney disease about their experiences receiving care. In their responses, patients expressed dissatisfaction with the lack of information they received from their health care providers and voiced a strong interest in learning more about the disease.

As kidney disease progresses to the later stages, patients get treated by kidney specialists called nephrologists, who provide patients with targeted treatment and more robust education. But by the time patients progress to late-stage disease or even kidney failure, many symptoms can’t be reversed and the disease is much harder to manage.

How can patients take charge of kidney health?

People who are at risk for chronic kidney disease or who have developed early-stage disease can take several steps to minimize the chances that it will progress to kidney failure.

First, patients can ask their doctors about chronic kidney disease, especially if they have risk factors such as high blood pressure or diabetes. Studies show that patients who ask questions, make requests and raise concerns with their provider during their health care visit have better health outcomes and are more satisfied with their care.

Some specific questions to ask include “Am I at risk of developing chronic kidney disease?” and “Have I been tested for chronic kidney disease?” To help patients start these conversations at the doctor’s office, researchers are working to develop digital tools that visually represent a patient’s kidney disease test results and risks. These graphics can be incorporated into patients’ medical records to help spur conversations during a health care visit about their kidney health.

Studies show that patients with chronic kidney disease who have a formal diagnosis in their medical records receive better care in line with current treatment guidelines and experience slower disease progression. Such patients can ask, “How quickly is my chronic kidney disease progressing?” and “How can I monitor my test results?” They may also want to ask, “What is my treatment plan for my chronic kidney disease?” and “Should I be seeing a kidney specialist?”

In our research, we saw that patients with chronic kidney disease who had seen a loved one experience dialysis treatment were especially motivated to stick with their treatment to prevent kidney failure.

But even without the benefit of direct experience, the possibility of kidney failure may motivate patients to follow their health care providers’ recommendations to eat a healthy diet, get regular physical activity and take their medications as prescribed.The Conversation

Eleanor Rivera, Assistant Professor of Population Health Nursing Science, University of Illinois Chicago

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Rethinking repression − why memory researchers reject the idea of recovered memories of trauma

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theconversation.com – Gabrielle Principe, Professor of Psychology, College of Charleston – 2025-03-24 07:52:00

Memories and photos both can misrepresent the past.
Westend61 via Getty Images

Gabrielle Principe, College of Charleston

In 1990, George Franklin was convicted of murder and sentenced to life in prison based on the testimony of his 28-year-old daughter Eileen. She described seeing him rape her best friend and then smash her skull with a rock.

When Eileen testified at her father’s trial, her memory of the murder was relatively fresh. It was less than a year old. Yet the murder happened 20 years earlier, when she was 8 years old.

How can you have a one-year-old memory of something that happened 20 years ago? According to the prosecution, Eileen repressed her memory of the murder. Then much later she recovered it in complete detail.

Can a memory of something so harrowing disappear for two decades and then resurface in a reliable form?

This case launched a huge debate between memory researchers like me who argue there is no credible scientific evidence that repressed memories exist and practicing clinicians who claim that repressed memories are real.

This controversy is not merely an academic one. Real people’s lives have been shattered by newly recollected traumatic experiences from childhood. I’ve seen this firsthand as a memory expert who consults on legal cases involving defendants accused of crimes they allegedly committed years or even decades ago. Often the only evidence linking the defendant to the crime is a recovered memory.

But the scientific community disagrees about the existence of the phenomenon of repressed memory.

Freud was the father of repression

Nineteenth-century psychoanalytic theorist Sigmund Freud developed the concept of repression. He considered it a defense mechanism people use to protect themselves from traumatic experiences that become too overwhelming.

The idea is that repression buries memories of trauma in your unconscious, where they – unlike other memories – reside unknown to you. They remain hidden, in a pristine, fixed form.

In Freud’s view, repressed memories make themselves known by leaking out in mental and physical symptoms – symptoms that can be relieved only through recovering the traumatic memory in a safe psychological environment.

In the 1980s, increasing numbers of therapists became concerned about the prevalence of child sexual abuse and the historical tendencies to dismiss or hide the maltreatment of children. This shift gave new life to the concept of repression.

Rise of repressed memory recovery

Therapists in this camp told clients that their symptoms, such as anxiety, depression or eating disorders, were the result of repressed memories of childhood sexual abuse that needed to be remembered to heal. To recover these memories, therapists used a range of techniques such as hypnosis, suggestive questioning, repeated imagining, bodywork and group sessions.

Did recovered-memory therapy work? Many people who entered therapy for common mental health issues did come out with new and unexpected memories of childhood sexual abuse and other trauma, without physical evidence or corroboration from others.

But were these memories real?

The notion of repressed memories runs counter to decades of scientific evidence demonstrating that traumatic events tend to be very well remembered over long intervals of time. Many victims of documented trauma, ranging from the Holocaust to combat exposure, torture and natural disasters, do not appear to be able to block out their memories.

In fact, trauma sometimes is too well remembered, as in the case of post-traumatic stress disorder. Recurrent and intrusive traumatic memories are a core symptom of PTSD.

No memory ≠ repressed memory

There are times when victims of trauma may not remember what happened. But this doesn’t necessarily mean the memory has been repressed. There are a range of alternative explanations for not remembering traumatic experiences.

Trauma, like anything you experience, can be forgotten as the result of memory decay. Details fade with time, and retrieving the right remnants of experience becomes increasingly difficult if not impossible.

Someone might make the deliberate choice to not think about upsetting events. Psychologists call this motivated forgetting or suppression.

There also are biological causes of forgetting such as brain injury and substance abuse.

Trauma also can interfere with the making of a memory in the first place. When stress becomes too big or too prolonged, attention can shift from the experience itself to attempts to regulate emotion, endure what’s happening or even survive. This narrow focus can result in little to no memory of what happened.

blank photo atop a stack of old black and white pictures
A forgotten memory isn’t just waiting around to be rediscovered – it’s gone.
malerapaso/E+ via Getty Images

False memories

If science rejects the notion of repressed memories, there’s still one question to confront: Where do newly recollected trauma memories, such as those triggered in recovered-memory therapy, come from?

All memories are subject to distortions when you mistakenly incorporate expectations, assumptions or information from others that was not part of the original event.

Memory researchers contend that memory recovery techniques might actually create false memories of things that never happened rather than resurrect existing memories of real experiences.

To study this possibility, researchers asked participants to elaborate on events that never happened using the same sorts of suggestive questioning techniques used by recovered-memory therapists.

What they found was startling. They were able to induce richly detailed false memories of a wide range of childhood traumatic experiences, such as choking, hospitalization and being a victim of a serious animal attack, in almost one-third of participants.

These researchers were intentionally planting false memories. But I don’t think intention would be necessary on the part of a sympathetic therapist working with a suffering client.

Are the memory wars over?

The belief in repressed memories remains well entrenched among the general public and mental health professionals. More than half believe that traumatic experiences can become repressed in the unconscious, where they lurk, waiting to be uncovered.

This remains the case even though in his later work, Freud revised his original concept of repression to argue that it doesn’t work on actual memories of experiences, but rather involves the inhibition of certain impulses, desires and fantasies. This revision rarely makes it into popular conceptions of repression.

As evidence of the current widespread belief in repressed memories, in the past few years several U.S. states and European countries have extended or abolished the statute of limitations for the prosecution of sexual crimes, which allows for testimony based on allegedly recovered memories of long-ago crimes.

Given the ease with which researchers can create false childhood memories, one of the unforeseen consequences of these changes is that falsely recovered memories of abuse might find their way into court – potentially leading to unfounded accusations and wrongful convictions.The Conversation

Gabrielle Principe, Professor of Psychology, College of Charleston

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How many types of insects are there in the world?

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theconversation.com – Nicholas Green, Assistant Professor of Biology, Kennesaw State University – 2025-03-24 07:48:00

This is a close-up photo of an ordinary garden fly.
Amith Nag Photography/Moment via Getty Images

Nicholas Green, Kennesaw State University

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to CuriousKidsUS@theconversation.com.


How many types of insects are there in the world? – Sawyer, age 8, Fuquay-Varina, North Carolina


Exploring anywhere on Earth, look closely and you’ll find insects. Check your backyard and you may see ants, beetles, crickets, wasps, mosquitoes and more. There are more kinds of insects than there are mammals, birds and plants combined. This fact has fascinated scientists for centuries.

One of the things biologists like me do is classify all living things into categories. Insects belong to a phylum called Arthropoda – animals with hard exoskeletons and jointed feet.

All insects are arthropods, but not all arthropods are insects. For instance, spiders, lobsters and millipedes are arthropods, but they’re not insects.

Instead, insects are a subgroup within Arthropoda, a class called “Insecta,” that is characterized by six legs, two antennae and three body segments – head, abdomen and the thorax, which is the part of the body between the head and abdomen.

A diagram of an ant, pointing out various body parts, including the antennae, thorax and legs.
The mandibles of the ants are its jaws; the petiole is the ant’s waist.
Vector Mine/iStock via Getty Images Plus

Most insects also have wings, although a few, like fleas, don’t. All have compound eyes, which means insects see very differently from the way people see. Instead of one lens per eye, they have many: a fly has 5,000 lenses; a dragonfly has 30,000. These types of eyes, though not great for clarity, are excellent at detecting movement.

What is a species?

All insects descend from a common ancestor that lived about about 480 million years ago. For context, that’s about 100 million years before any of our vertebrate ancestors – animals with a backbone – ever walked on land.

A species is the most basic unit that biologists use to classify living things. When people use words like “ant” or “fly” or “butterfly” they are referring not to species, but to categories that may contain hundreds, thousands or tens of thousands of species. For example, about 18,000 species of butterfly exist – think monarch, zebra swallowtail or cabbage white.

Basically, species are a group that can interbreed with each other, but not with other groups. One obvious example: bees can’t interbreed with ants.

But brown-belted bumblebees and red-belted bumblebees can’t interbreed either, so they are different species of bumblebee.

Each species has a unique scientific name – like Bombus griseocollis for the brown-belted bumblebee – so scientists can be sure which species they’re talking about.

This close-up of a dragonfly reveals its blue head, bulging compound eyes and black antennae.
This is what a dragonfly looks like up close.
Dieter Meyrl/E+ via Getty Images

Quadrillions of ants

Counting the exact number of insect species is probably impossible. Every year, some species go extinct, while some evolve anew. Even if we could magically freeze time and survey the entire Earth all at once, experts would disagree on the distinctiveness or identity of some species. So instead of counting, researchers use statistical analysis to make an estimate.

One scientist did just that. He published his answer in a 2018 research paper. His calculations showed there are approximately 5.5 million insect species, with the correct number almost certainly between 2.6 and 7.2 million.

Beetles alone account for almost one-third of the number, about 1.5 million species. By comparison, there are “only” an estimated 22,000 species of ants. This and other studies have also estimated about 3,500 species of mosquitoes, 120,000 species of flies and 30,000 species of grasshoppers and crickets.

The estimate of 5.5 million species of insects is interesting. What’s even more remarkable is that because scientists have found only about 1 million species, that means more than 4.5 million species are still waiting for someone to discover them. In other words, over 80% of the Earth’s insect biodiversity is still unknown.

Add up the total population and biomass of the insects, and the numbers are even more staggering. The 22,000 species of ants comprise about 20,000,000,000,000,000 individuals – that’s 20 quadrillion ants. And if a typical ant weighs about 0.0001 ounces (3 milligrams) – or one ten-thousandth of an ounce – that means all the ants on Earth together weigh more than 132 billion pounds (about 60 billion kilograms).

That’s the equivalent of about 7 million school buses, 600 aircraft carriers or about 20% of the weight of all humans on Earth combined.

YouTube video
For every person on Earth, it’s estimated there are 200 million insects.

Many insect species are going extinct

All of this has potentially huge implications for our own human species. Insects affect us in countless ways. People depend on them for crop pollination, industrial products and medicine. Other insects can harm us by transmitting disease or eating our crops.

Most insects have little to no direct impact on people, but they are integral parts of their ecosystems. This is why entomologists – bug scientists – say we should leave insects alone as much as possible. Most of them are harmless to people, and they are critical to the environment.

It is sobering to note that although millions of undiscovered insect species may be out there, many will go extinct before people have a chance to discover them. Largely due to human activity, a significant proportion of Earth’s biodiversity – including insects – may ultimately be forever lost.


Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.The Conversation

Nicholas Green, Assistant Professor of Biology, Kennesaw State University

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