Dogs can smell when people are stressed, and it seems to make them feel downhearted.

Humans and dogs have been close companions for around 30,000 years, based on anthropological and DNA evidence. This long history suggests dogs are particularly attuned to interpreting human emotions. They have evolved to read verbal and visual cues from their owners, and previous studies have shown that their acute sense of smell allows them to detect stress in human sweat. Now, researchers have found that not only can dogs smell stress—manifested as higher levels of the hormone cortisol—but they also react to it emotionally.

In a new study published Monday in Scientific Reports, scientists from the University of Bristol in England recruited 18 dogs of various breeds, along with their owners. Eleven volunteers, unfamiliar to the dogs, underwent a stress test involving public speaking and arithmetic, while samples of their underarm sweat were collected on cloths for analysis.

Next, the human participants took part in a relaxation exercise, which involved watching a nature video while seated on a beanbag chair under dim lighting. After this, new sweat samples were collected. Sweat samples from three of these volunteers were used in the study.

The participating dogs were divided into three groups and exposed to sweat samples from one of the three volunteers. Before this, the dogs were trained to associate a food bowl at one location with a treat and a bowl at another location with no treat.

During testing, bowls without treats were occasionally placed in one of three “ambiguous” locations. In one session, when the dogs smelled the sweat sample from a stressed volunteer, they were less likely to approach the bowl in the ambiguous location compared to when they smelled a cloth without a sample. This suggested that the dogs believed the bowl did not contain a treat. Previous research indicates that expecting a negative outcome reflects a down mood in dogs.

The results suggest that when dogs are around stressed individuals, they become more pessimistic about uncertain situations. In contrast, being near people with a relaxed odor does not have this effect. This was explained by Zoe Parr-Cortes, the lead study author and a Ph.D. student at Bristol Veterinary School, University of Bristol.

“For thousands of years, dogs have evolved alongside us, learning to live with humans,” says Zoe Parr-Cortes. “Both humans and dogs are social animals, and there’s an emotional contagion between us. Being able to sense stress from another member of the pack would have been beneficial, as it alerted them to a threat that the other member had already detected.”

Katherine A. Houpt, a professor emeritus of behavioral medicine at Cornell University’s College of Veterinary Medicine, explains that the fact the odor came from an unfamiliar individual highlights the importance of smell for dogs and its influence on their emotions in practical situations.

Houpt, who was not involved in the study, suggests that the smell of stress might have reduced the dogs’ hunger, as stress is known to affect appetite. “It might not be changing their decision-making, but rather their motivation for food,” she says. “It makes sense because when you’re super stressed, you’re not as interested in that candy bar.”

This research, Houpt adds, demonstrates that dogs have empathy based on smell, in addition to visual and verbal cues. When you’re stressed, she suggests, it could lead to behaviors in your dog that aren’t typically seen. Moreover, it raises questions about how stress might affect dogs when they’re exposed to the heightened anxiety of their owners.

“If dogs are responding to mild stress like this, I’d be curious to see how they react to more intense situations, such as an impending tornado, losing a job, or failing a test,” Houpt says. “One would expect the dog to be even more attuned to a real threat.”

Last Updated on November 21, 2024 by News Time

“We Now Know the Nerve Behind Dogs Shaking Water on Your Clothes”

“If you’ve ever spent time with a dog, you’ve likely experienced this: you’re lounging by the pool on a hot day, tossing a stick for your furry friend. After fetching it, Fido trots over, flashes a doggy grin, and shakes cold water all over your dry clothes.”

“Scientists have finally uncovered the reason behind the infamous ‘wet dog shake.’ New research reveals that a receptor in mammal skin called C-LTMR is responsible for this behavior. When droplets of liquid land on the back of the neck, it triggers a consistent shaking response in furry animals, from dogs and cats to mice.”

“It’s a complicated behavior,” said Dawei Zhang, co-author of the research and a doctoral student at the Howard Hughes Medical Institute of Harvard Medical School.

The study, published today (Nov. 7) in Science journal, reveals new insights into the “wet dog shake.” According to Zhang, animals across species tend to shake at the same frequency, typically with three back-and-forth shakes, but until now, researchers didn’t know which receptors and nerves were responsible for this behavior.

New genetic tools allowed Zhang and his colleagues to uncover the cause of the “wet dog shake.” The team began by creating genetic mutations in mice to knock out either the channels in skin receptors that detect mechanical forces or the receptors that respond to temperature changes. This approach helped them pinpoint the culprit behind the shaking behavior.

The researchers discovered that mice unable to detect temperature changes still performed the “wet dog shake” when droplets of oil were sprinkled on their necks — the most reliable way to trigger the behavior. However, mice lacking mechanoreceptor channels, which detect mechanical forces, did not shake at all.

Zhang and his team zeroed in on mechanoreceptors, tracking their activity in response to the oil droplets. They identified three receptors that respond to very light touch. Using optogenetics, a technique that activates specific receptors with light, they were able to trigger the individual nerve types without needing any liquid stimulus, further pinpointing the source of the shaking behavior.

The results were conclusive: when the researchers stimulated a type of nerve called C-fiber low-threshold mechanoreceptors (C-LTMRs), the mice shook as though they’d just been sprayed with water. To confirm their findings, they engineered mice without C-LTMRs and discovered that these mice shook 58% less than normal mice when drizzled with water.

C-LTMRs have long been a mystery, Zhang explained. While research conducted 80 years ago suggested they might be responsible for creating ticklish sensations in animals, it wasn’t clear how animals experienced this stimulus. In humans, similar mechanoreceptors called C-mechanoreceptors are linked to pleasurable, brushing sensations on the skin.

Last Updated on November 21, 2024 by News Time

Why Do Dogs Look Like Their Owners?

It’s a common phenomenon: dogs and their owners seem to bear striking resemblances to each other. Whether it’s the shape of the face, the color of the hair, or even the way they carry themselves, many dog owners find themselves drawing comparisons between themselves and their pets. But is there any science behind this? Why do dogs look like their owners? Let’s explore the reasons behind this fascinating phenomenon.

1. The Power of Selection
One of the main reasons dogs resemble their owners is the simple act of selection. When people adopt or purchase a dog, they are often subconsciously drawn to dogs that resemble them in some way. It could be the dog’s breed, physical traits, or even personality.

Studies have shown that people tend to choose dogs that match their own facial features or even their emotional temperament. For example, people with round faces might gravitate toward breeds like Cocker Spaniels or Bulldogs, while those with angular faces might lean towards dogs like Greyhounds or Dobermans. This selection process is often subtle and unconscious but influences the bond between the pet and the owner.

2. Shared Environment and Lifestyle
The longer a person lives with a dog, the more likely they are to share similar habits, movements, and facial expressions with their pet. Dogs often mirror their owners’ behavior and moods, and in turn, owners begin to imitate their dogs’ behavior. Over time, this shared environment can lead to physical similarities, too.

For example, if an owner frequently smiles or has a cheerful demeanor, their dog may display a similar “happy” expression. Likewise, owners who are calm and relaxed may have a dog that exudes the same sense of tranquility. This “contagion effect” works both ways — dogs tend to mimic their owners’ emotional states, and owners often subconsciously mirror their dogs’ expressions.

3. Facial Recognition The Science of Similarity
A 2004 study published in *Psychological Science* explored the link between dog-owner resemblances. The research found that people were able to match photos of dogs with their owners based on appearance alone, even when the pair wasn’t familiar to the observer. This suggests that there may be a subconscious connection between dog and owner features.

According to the study’s findings, people tend to identify facial similarities between themselves and their dogs because they subconsciously focus on key facial features such as the eyes, mouth, and overall shape. For instance, a person with a strong jawline might notice a similar jaw structure in their dog, even if the dog has a different overall body shape.

4. Evolutionary Influence  Canine Companionship and Human Nature**
There’s also an argument to be made from an evolutionary perspective. Humans have been living alongside dogs for thousands of years, and in that time, a unique bond has formed. Dogs have evolved to communicate with humans through body language, facial expressions, and even vocalizations. In turn, humans have developed a keen ability to read and mirror their dogs’ expressions.

This mirroring effect likely goes beyond just physical resemblance. It’s a reflection of the deeper emotional and psychological connection between dogs and their owners. Over generations, the bond between humans and dogs has led to a shared understanding of each other’s needs and behaviors, which may explain why dogs and owners sometimes begin to look alike.

5. Dogs Can Mimic Their Owners’ Emotions
Another factor in why dogs resemble their owners might be the emotional connection they share. Research has shown that dogs are highly sensitive to their owner’s emotions, and they often mimic those feelings. When a dog feels its owner is happy, calm, or anxious, the dog may adjust its behavior or expression accordingly.

This emotional mirroring extends to facial expressions, too. If an owner frequently displays a certain expression — for example, smiling or frowning — the dog might adopt a similar look. Some researchers believe this emotional synchrony between humans and their dogs contributes to the physical resemblance that we often see.

6.The Role of Genetics and Breeding
While selection and environmental factors play a large part in why dogs resemble their owners, genetics and breeding also come into play. People who are fond of certain breeds or have a preference for a specific type of dog may inadvertently select a dog with similar genetic traits to their own. For example, certain breeds might be chosen because they possess physical characteristics that owners find attractive, which can influence the perceived resemblance between pet and owner.

Additionally, over time, people may have bred dogs to possess certain traits that appeal to human sensibilities, from personality traits to physical appearance. In the case of purebred dogs, there’s often a consistency in physical traits that can lead to similarities between owners and their pets, especially if the owner is particularly fond of that breed’s unique characteristics.

7. Cultural Influences
Cultural trends can also influence the types of dogs people choose. For instance, certain dog breeds are more popular in specific regions or social circles, and these breeds often reflect cultural values or trends. In such cases, the physical traits of the dog may align with the preferences or appearance of the people in that culture.

In some cultures, for example, smaller, lap-sized dogs are often favored, and these breeds may resemble their owners in terms of size and demeanor. Similarly, larger or more rugged breeds might be more popular in outdoor or rural communities, where their physical traits mirror the active, sturdy lifestyle of their owners.

Conclusion: A Connection Beyond the Surface
While the idea that dogs look like their owners is often rooted in coincidence, selection, and environmental factors, it’s clear that the bond between a dog and its owner runs deeper than just physical appearance. Dogs and their owners share not only a home but also experiences, emotions, and even body language that create an extraordinary connection.

Ultimately, whether through genetics, shared experiences, or simple mirroring, the relationship between dogs and their owners is one of the most unique and rewarding bonds in the animal kingdom — and it’s no wonder that, over time, they might begin to look alike.

Last Updated on November 18, 2024 by News Time