Contagious Yawning in Dogs and Humans: Are dogs more empathetic towards their owners?

(National Geographic, 8, August 2013) - Pets yawn more in response to owners' yawns than strangers', study says.

Journal article: Familiarity Bias and Physiological Responses in Contagious Yawning by Dogs Support Link to Empathy

Dog owners who claim their pets know their feelings may be on to something: A new study shows that canines yawn more in response to their owners' yawns than they do to strangers' yawns.

That suggests dogs are "emotionally connected" to people, study leader Teresa Romero of the University of Tokyo said in a statement.

Scientists already knew that dogs sometimes yawn when they see people yawn, but it was unclear if that was considered a form of empathy or mild stress, as yawning can be caused by anxiety.

So Romero and her team set up an experiment in which 25 pet dogs watched both their owners and strangers yawn or pretend to yawn. (Read about why people yawn.)

The team ruled out stress when researchers saw no significant differences in the dogs' heartbeats during the experiments, according to the study, published August 7 in the journal PloS ONE.

Not only did the dogs in the study yawn more in response to their owners' yawns, they also yawned less when they saw fake yawns from their owners or from strangers, suggesting they were exhibiting true contagious yawning.

Contagious yawning occurs in humans, chimpanzees, baboons, and dogs.

In a similar study published last year, scientists found that people yawn more in response to the yawns of people they care about most.

In the case of people, scientists suspect that contagious yawning is a form of empathizing with people experiencing a feeling, which—in the case of yawning—usually means stress, anxiety, boredom, or fatigue.

Elisabetta Palagi, of the Institute of Cognitive Sciences and Technologies in Rome, noted that the study is the first time that scientists have shown contagious yawning occurring between different species.

"This could be the result of a long process of domestication," said Palagi, who wasn't involved in the study.  "Once more," she said, the study "demonstrates that dogs are capable of empathic abilities toward humans."

Dog and Human Genomes Evolved Together

(National Geographic, 14, May 2013) - Evolution shaped genes in humans and dogs that correspond to diet, behaviour, and disease, according to a new study.

The bond between dogs and humans is ancient and enduring. Dogs snuggle up to us at night, gambol by our side during daily walks, and flop adoringly at our feet when we crash on our couches. But new research shows that the connection runs deeper than you might think. It is embedded in our genes.

Researchers from the University of Chicago and several international institutions found that several groups of genes in humans and dogs—including those related to diet and digestion, neurological processes, and disease—have been evolving in parallel for thousands of years.

This parallel evolution was likely driven by the shared environments of humans and dogs, wrote the authors in a study published May 14 in the journal Nature Communications.

"As domestication is often associated with large increases in population density and crowded living conditions, these 'unfavourable' environments might be the selective pressure that drove the rewiring of both species," the authors surmise.

For example, living in crowded conditions with humans may have conferred an advantage on less aggressive dogs, leading to more submissive canines and eventually to the pets whose puppy-dog eyes gaze at us with unconditional affection.

The study authors suggest that dogs were domesticated 32,000 years ago; that's much earlier than current estimates, which place domestication at around 15,000 to 16,000 years ago.

"Thirty-two thousand is a little bit old," said Bob Wayne, an evolutionary biologist at the University of California, Los Angeles. Although he does acknowledge that the timing of a split between wolves and dogs has varied widely—ranging between 6,000 and 120,000 years ago.

The study authors also proposed that dog domestication originated in Southeast Asia, rather than the Middle East, as others have suggested.

The scientists involved in the study sequenced the genomes of four gray wolves from Russia and China, three Chinese street dogs, and three domesticated breeds—including a German shepherd, a Belgian malinois, and a Tibetan mastiff.

They were then able to figure out which genes were associated with domestication and how far back that shift may have occurred. The team also looked at the dog genes selected for during domestication and compared them with human genes.

"The history of dog domestication is often depicted as a two-stage process," wrote Weiwei Zhai, a genetics researcher at the Chinese Academy of Sciences in Beijing and a study co-author, in an email. "The first stage is from wolves to dogs. The second stage is from dogs to breeds." (Read "How to Build a Dog" in National Geographic magazine.)

Southeastern Asia street dogs, including the Chinese street dogs in the study, may be an evolutionary bridge between wolves and purebred dogs due to their greater genetic diversity when compared with other street dogs from around the world, Zhai explained. This would make the Chinese street dogs a kind of "missing link" among canines.

When Zhai and colleagues took their canine sequences and compared them with the human genome, the team found that sequences for things such as the transport of neurotransmitters like serotonin, cholesterol processing, and cancer have been selected for in both humans and dogs.

Though selection in the same gene in two different species, known as convergent evolution, is rare in nature, said Zhai, their results weren't too surprising. After all, humans and dogs have shared the same living environment for years.

In addition to sharing genes that deal with diet and behavior, dogs and humans also share diseases, including obesity, obsessive-compulsive disorder, epilepsy, and some cancers including breast cancer, wrote Ya-ping Zhang, a professor at the Chinese Academy of Sciences in Kunming (map), in an email.

This might be due to the fact that genes often have multiple effects, explained Zhai. "Some of the effects will be beneficial, while others can be deleterious. When the selective advantage outweighs the deleterious cost, the gene can still be selected [for]."

The cancer-related genes the research team found evolving together in both dogs and humans could be the result of processes like this, said Zhai.

"This is nice that [their study is] based on complete genome data," said UCLA's Wayne, who provided reference data the study authors compared with their genetic sequences. Other studies have used only snippets, such as mitochondrial DNA.

But he cautioned that comparing human and canine genomes can be tricky, adding that the evaluation of canine sequences from other places in addition to China and Russia would have helped in the dating of domestication and in establishing its location.

Furthermore, Wayne said, without further comparisons between humans and other domestic animals like goats or horses, it's hard to know whether the parallel evolution in the genomes of humans and dogs is unique or not.

Even so, he added, the study adds another chapter to the story of dog domestication—a story far from over.

Sneaky Canines: No Longer Out of Sight Out of Mind – [Article]

Om nom nom nom

(University of Portsmouth, 11, Feb 2013) - Domestic dogs are much more likely to steal food when they think nobody can see them, suggesting for the first time they are capable of understanding a human’s point of view.

Many dog owners think their pets are clever or that they understand humans but, until now, this has not been tested by science.

Dr Juliane Kaminski, of the University of Portsmouth’s Department of Psychology, has shown that when a human forbids a dog from taking food, dogs are four times more likely to disobey in a dark room than a lit room, suggesting they take into account what the human can or cannot see.

Dr Kaminski said: “That’s incredible because it implies dogs understand the human can’t see them, meaning they might understand the human perspective.”

This is the first study to examine if dogs differentiate between different levels of light when they are developing strategies on whether to steal food. It is published in the journal Animal Cognition. The research was funded by the Max Planck Society, Dr Kaminski’s former employer.

Dr Kaminski said: “Humans constantly attribute certain qualities and emotions to other living things. We know that our own dog is clever or sensitive, but that’s us thinking, not them.

“These results suggest humans might be right, where dogs are concerned, but we still can’t be completely sure if the results mean dogs have a truly flexible understanding of the mind and others’ minds. It has always been assumed only humans had this ability.”

The research is an incremental step in our understanding of dogs’ ability to think and understand which could, in turn, be of use to those who work with dogs, including the police, the blind and those who use gun dogs, as well as those who keep them as pets.

Dr Kaminski ran a series of experiments in varied light conditions. In each test, a dog was forbidden by a human from taking the food. When the room was dark, the dogs took more food and took it more quickly than when the room was lit.

The tests were complex and involved many variables to rule out that dogs were basing their decisions on simple associative rules, for example, that dark means food.

There is no evidence on how well dogs can see in the dark, but the results of this research show dogs can differentiate between light and dark.

Dr Kaminski said: “The results of these tests suggest that dogs are deciding it’s safer to steal the food when the room is dark because they understand something of the human’s perspective.”

Dogs’ understanding may be limited to the here and now, rather than on any higher understanding, Dr Kaminski said, and more research is needed to identify what mechanisms are controlling dogs’ behaviour.

In total, 42 female and 42 male domestic dogs aged one year or older took part in the tests. They were chosen only if they were comfortable without their owners in the room, even in complete darkness, and if they were interested in food. “Some dogs are more interested in by food than others,” Dr Kaminski said.

Previous studies have shown chimpanzees have a sophisticated understanding and seem to know when someone else can or can’t see them and can also remember what others have seen in the past. It is not known how sophisticated dogs’ understanding is in comparison. Many earlier research papers have found that, for dogs, a human’s eyes are an important signal when deciding how to behave, and that they respond more willingly to attentive humans, than inattentive ones.

An Old Wolf Can't Learn New Tricks, But Dogs Can - [Article]

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(Science Daily, 17, Jan 2013) - Dogs and wolves are genetically so similar; it's been difficult for biologists to understand why wolves remain fiercely wild, while dogs can gladly become "man's best friend." Now, doctoral research by evolutionary biologist Kathryn Lord at the University of Massachusetts Amherst suggests the different behaviours are related to the animals' earliest sensory experiences and the critical period of socialization. Details appear in the current issue of Ethology.

Journal article: A Comparison of the Sensory Development of Wolves (Canis lupus lupus) and Dogs (Canis lupus familiaris)

Until now, little was known about sensory development in wolf pups, and assumptions were usually extrapolated from what is known for dogs, Lord explains. This would be reasonable, except scientists already know there are significant differences in early development between wolf and dog pups, chief among them timing of the ability to walk, she adds.

To address this knowledge gap, she studied responses of seven wolf pups and 43 dogs to both familiar and new smells, sounds and visual stimuli, tested them weekly, and found they did develop their senses at the same time. But her study also revealed new information about how the two subspecies of Canis lupus experience their environment during a four-week developmental window called the critical period of socialization, and the new facts may significantly change understanding of wolf and dog development.

When the socialization window is open, wolf and dog pups begin walking and exploring without fear and will retain familiarity throughout their lives with those things they contact. Domestic dogs can be introduced to humans, horses and even cats at this stage and be comfortable with them forever. But as the period progresses, fear increases and after the window closes, new sights, sounds and smells will elicit a fear response.

Through observations, Lord confirmed that both wolf pups and dogs develop the sense of smell at age two weeks, hearing at four weeks and vision by age six weeks on average. However, these two subspecies enter the critical period of socialization at different ages. Dogs begin the period at four weeks, while wolves begin at two weeks. Therefore, how each subspecies experiences the world during that all-important month is extremely different, and likely leads to different developmental paths, she says.

Lord reports for the first time that wolf pups are still blind and deaf when they begin to walk and explore their environment at age two weeks. "No one knew this about wolves, that when they begin exploring they're blind and deaf and rely primarily on smell at this stage, so this is very exciting," she notes.  She adds, "When wolf pups first start to hear, they are frightened of the new sounds initially, and when they first start to see they are also initially afraid of new visual stimuli. As each sense engages, wolf pups experience a new round of sensory shocks that dog puppies do not."

Meanwhile, dog pups only begin to explore and walk after all three senses, smell, hearing and sight, are functioning. Overall, "It's quite startling how different dogs and wolves are from each other at that early age, given how close they are genetically. A litter of dog puppies at two weeks are just basically little puddles, unable to get up or walk around. But wolf pups are exploring actively, walking strongly with good coordination and starting to be able to climb up little steps and hills."

These significant, development-related differences in dog and wolf pups' experiences put them on distinctly different trajectories in relation to the ability to form inter-species social attachments, notably with humans, Lord says. This new information has implications for managing wild and captive wolf populations, she says.

Her experiments analysed the behaviour of three groups of young animals: 11 wolves from three litters and 43 dogs total. Of the dogs, 33 border collies and German shepherds were raised by their mothers and a control group of 10 German shepherd pups were hand-raised, meaning a human was introduced soon after birth.

At the gene level, she adds, "the difference may not be in the gene itself, but in when the gene is turned on. The data help to explain why, if you want to socialize a dog with a human or a horse, all you need is 90 minutes to introduce them between the ages of four and eight weeks. After that, a dog will not be afraid of humans or whatever else you introduced. Of course, to build a real relationship takes more time. But with a wolf pup, achieving even close to the same fear reduction requires 24-hour contact starting before age three weeks, and even then you won't get the same attachment or lack of fear."