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Tag: study

How farming changed dogs — and us

bread

It’s no big surprise — given it’s what led them to befriend us in the first place — that dogs have been dining on our scraps since early in their domestication.

What’s more interesting is how dogs adapted to our junk food ways.

A team of researchers from France, Sweden and Romania has found evidence indicating that domesticated dogs underwent a genetic transformation, developing multiple copies of a gene that aids in the digestion of starch.

That’s the same thing we humans did, when we made the transition from a hunting to a farming society, consuming more starches and vegetable and less meat.

In their paper published in the journal Royal Society Open Science, the team describes what they found out by conducting a DNA analysis of ancient dog teeth and other bones.

They conclude that, around 7000 years ago, domesticated dogs were eating so much wheat and millet they made extra copies of starch-digesting genes to help them cope.

starchIn other words, as we began consuming more starches, so too — via our leftovers — did the dogs that were compromising their wolfy ways to hang around with us.

That we and dogs can have our genes altered by the food we consume and the repeated behaviors we engage in, is kind of intriguing, and kind of scary — and it brings new credence to the old phrase “you are what you eat.”

Some of the first insights into how farming changed the canine genome came three years ago, according to Sciencemag.com

That’s when a team led by evolutionary geneticist Erik Axelsson of Uppsala University in Sweden discovered that dogs have four to 30 copies of a gene called Amy2B, whereas wolves typically only have two.

The new study sought to get a better handle on when that happened.

Axelsson teamed up with Morgane Ollivier, a paleogeneticist at Ecole Normale Supéieure de Lyon in France and others, who extracted ancient DNA from the bones and teeth of 13 wolf and dog specimens collected from archaeological sites throughout Eurasia.

Four of the ancient dogs — from a 7000-year-old site in Romania and 5000-year-old sites in Turkey and France — had more than eight copies of Amy2B, Ollivier and his colleagues reported in Royal Society Open Science.

The findings rule out a modern origin for the increase in the number of Amy2B genes in dogs.

pastaDogs were likely domesticated more than 15,000 years ago, and likely continued eating mostly meat after that, as they became hunting companions to humans.

As humans turned to farming, the number of copies of Amy2B increased — first in us, then in dogs.

Being able to survive on whatever humans discarded likely enabled dogs to become widespread as people migrated across the globe, the scientists say.

It’s food for thought — how what we eat, or other repeated practices, can lead, far down the road, to alterations in our DNA.

Might scientists discover, generations from now, for example, that we humans have developed a selfie-taking gene that won’t let us stop taking excessive photos of ourselves?

They’ll name it 02BME.

The nose knows but the ears tell

hotears

Many of us may be most familiar with infrared thermography from its least valuable (I’d argue) use — ghost hunting.

It serves many far more sophisticated purposes, though, than providing fodder for those shaky-camera paranormal TV shows — from assessing medical conditions to military reconnaissance, from finding missing children to sensing mood changes in humans.

And, no big surprise, dogs.

In the latest post on Dog Spies, her blog on Scientific American, Julie Hecht recounted a recent study at the Animal Behavior, Cognition and Welfare Research Group at the University of Lincoln in the UK.

Researchers found, through infrared thermography, that the ear temperature of dogs decreased (turning blue on the camera) when they were isolated, and warmed backed up (turning red) when they reunited with people.

It’s similar to findings in studies of human stress levels — except in humans it’s the nose, instead of the ears, that is the most common giveaway.

As Hecht explained, infrared thermography picks up changes in surface temperature. When frightened, stressed or placed in unfamiliar surroundings, blood rushes away from your extremities, in dogs and humans. They get cooler as your core gets warmer and ready to react to whatever threat may be ahead.

The tip of a scared person’s nose gets cooler in such situations, just as rat paws and tails have been shown to do in experiments. In rabbits and sheep, the ears are the most obvious indicator.

Stefanie Riemer and colleagues placed dogs for brief periods in an isolated and novel environment. As the researchers expected, thermographic images of the dogs in isolation showed their ear temperature increasing, then rising when they were reunited with people.

The study appears in the current issue of Physiology & Behavior.

Six dogs were included in the study, and several were found to be unsuitable for study because their fur was too dense to get a good reading.

It seems like a technology that could be put to good use when it comes to studying dogs, and in learning more about those with behavioral issues and what triggers them.

That seems to me a better pursuit than chasing ghosts who aren’t really bothering anybody. Non-invasive, physically, as it is, even infrared photography has the potential for being cruel.

In a study in Italy two years ago, 20 bank tellers who had been robbed at gunpoint were shown a series of faces — happy, neutral, angry, etc. On the fifth face, the researchers exposed them to a loud and unexpected blast, and recorded, thermographically, how the blood left the noses and face.

Half of the tellers had already been diagnosed with PTSD.

Whether the researchers ended up giving PTSD to the other half is not addressed in the study.

(Photo: S. Riemer / Physiology & Behavior)

Dig this: Uncovered tooth shows Mesolithic man took road trips — and with dogs

stonehenge

Archaeologists say they have uncovered evidence that dogs weren’t just already domesticated by man 7,000 years ago, but they were taking road trips with him as well.

They say a dog’s tooth found one mile from Stonehenge is the earliest evidence of people traveling to the site of the prehistoric monument — even before its famous rock formation was constructed, believed to be 5,000 years ago.

An isotope analysis of the tooth’s enamel at Durham University showed the dog originally hailed from York, or at least had consumed water there. Bones found near the site suggest the dog feasted on salmon, trout, pike, wild pig and red deer.

toothThe dog most likely resembled a German shepherd, but with a more distinctly wolf-like appearance.

Researchers believe the dog made the 250-mile trip from York to Wiltshire 7,000 years ago with a Mesolithic hunter-gatherer.

Possibly, they say, he was taking it there to trade.

Archaeologist David Jacques, who leads the team digging at an encampment site called Blick Mead, said the findings show that dogs were domesticated by Mesolithic times, and that, contrary to popular thought, man was doing some long distance travel back then.

And it shows that what’s now the world’s most famous prehistoric monument was drawing people from afar even before whoever arranged those rocks arranged those rocks.

“The fact that a dog and a group of people were coming to the area from such a long distance away further underlines just how important the place was four millennia before the circle was built,” said Jacques, a senior research fellow at the University of Buckingham.

As the decade-long dig continues, The Guardian reported, evidence is accumulating that Stonehenge — as long as 7,000 years ago — was a gathering place.

“It makes us wonder if this place is a hub point, a really important place for the spread of ideas, new technologies and probably genes,” Jacques said.

Our guess? It was a flea market.

Dogs are better at filtering out useless info

While both human children and dogs learn from copying adult humans, dogs are better at spotting the bullshit.

So says (though not in those words) a new study from Yale University’s Canine Cognition Center.

Imitation, in addition to being the sincerest form of flattery, is how we — be we a puppy or a baby — learn. But young humans tend to be more trusting, following adult advice exactly. Dogs are more likely to see a shorter route to accomplishing the goal and opt for it, filtering out unnecessary steps that are just a waste of time.

(Might this explain why dogs don’t watch television all that much, or get on the Internet?)

In the experiment, researchers presented over 40 breeds of dogs with treats hidden inside puzzles.

They showed the dogs the steps necessary to solving the puzzle, but in doing so they included many unnecessary steps.

When the dogs’ turn came to solve the puzzle, they skipped the irrelevant steps that had nothing to do with getting to the treats, showing that dogs are able, or at least more able than human children, to separate bad advice from good advice.

Researchers contrasted their study results with those from a similar study at Yale that examined children, and they found humans relied more on imitation than the dogs. The children, after watching an adult solve the puzzle, tended to duplicate every step — even the unnecessary ones.

The study is similar to one about a decade ago that compared chimpanzees with human puzzle solvers. Chimpanzees, while prone to imitation, were slightly better at discerning the unnecessary steps and avoiding them than humans.

“So this tells us something really important about how humans learn relative to other animals,” said Yale Professor of Psychology Laurie Santos, one of the study’s authors. “We’re really trusting of the information that we get from other individuals – even more trusting than dogs are.”

“And what this means is we have to be really careful about the kinds of information we present ourselves with,” she added. “We’re not going to have the right filter for bad information, so we should stick to looking at information that’s going to be positive, information that’s going to be good.”

Or, as easily duped as our species is, we could just let dogs give us the advice.

It’s what you say AND how you say it

enik kubinyi

Traditional wisdom holds that it’s not so much what you say to your dog as how you say it that counts — that tone, in other words, is everything.

But scientists in Hungary say dogs may understand more words than we think — and that it takes a combination of positive words and a positive tone for their brains to register a pleasurable reaction.

“Both what we say and how we say it matters to dogs,” said Attila Andics, a research fellow at Eotvos Lorand University in Budapest.

MRI readings conducted in the study showed the right hemisphere of dogs’ brains react to intonation, while the left hemisphere reacts to the meaning of words — as is the case with humans.

Their paper was published in this week’s issue of the journal Science.

The researchers — using words, positive tones and plenty of treats, we’d imagine — trained dogs to enter a magnetic resonance imaging machine and lie still while the machine recorded their brain activity.

The methods, similar to those being used at Emory University, are allowing scientists to better understand what goes on in the canine brain.

enik kubinyi2A trainer spoke common words of praise used by dog owners, including the Hungarian words for “good boy,” “super” and “well done,” as well as neutral words like “however” and “nevertheless.”

All the words were spoken using both positive tones and neutral tones, according to the New York Times.

Only words of praise spoken in a positive tone provoked significant reactions, making the reward centers in a dog’s brain light up.

The researchers at Eötvös Loránd University in Budapest recruited 13 family dogs for the study, and trained them to sit totally still for seven minutes in an fMRI scanner. The dogs were not restrained, and “could leave the scanner at any time,” the authors said.

Using the brain activity images, the researchers saw that the dogs processed the familiar words regardless of intonation, and they did so using the left hemisphere, just like humans. Tone, on the other hand, was analyzed in the auditory regions of the right hemisphere.

Using neutral words in a positive tone, or positive words in a neutral tone, produced little reaction — or at least not one that shows up in MRI machines.

“It shows that for dogs a nice praise can very well work as a reward, but it works best if both words and intonation match,” Andics said. “So dogs not only tell apart what we say and how we say it, but they can also combine the two, for a correct interpretation of what those words really meant.”

(Photos by Enik Kubinya, via New York Times)

Which motivates more — food or praise?

kadypraise

A study at Emory University suggests that dogs aren’t strictly the food-obsessed beasts they’ve traditionally been seen as — and that many, maybe even most, prefer attention and praise over a chewy treat.

While only 13 dogs participated in the study, there were only two of them who — judging from their neural reactions — showed a distinct preference for food over praise.

The study, published in the journal Social, Cognitive and Affective Neuroscience, is one of the first to combine brain-imaging data with behavioral experiments to explore what kind of rewards canines prefer.

“We are trying to understand the basis of the dog-human bond and whether it’s mainly about food, or about the relationship itself,” says Gregory Berns, a neuroscientist at Emory and lead author of the research.

“Out of the 13 dogs that completed the study, we found that most of them either preferred praise from their owners over food, or they appeared to like both equally. Only two of the dogs were real chowhounds, showing a strong preference for the food.”

Berns heads the Dog Project in Emory’s Department of Psychology. It was the first to train dogs to voluntarily enter a functional magnetic resonance imaging (fMRI) scanner and remain motionless during scanning, without restraint or sedation.

Their previous research using the technique identified the ventral caudate region of the canine brain as a reward center and showed that region responds more strongly to the scents of familiar humans than to the scents of other humans, or even to those of familiar dogs.

Phys.org reports that, in the new study, researchers trained the dogs to associate three different objects with different outcomes. A pink toy truck signaled a food reward; a blue toy knight signaled verbal praise from the owner; and a hairbrush signaled no reward, to serve as a control.

The dogs then were tested on the three objects while in an fMRI machine. Each dog underwent 32 trials for each of the three objects as their neural activity was recorded.

Four of the dogs showed a particularly strong activation for the stimulus that signaled praise from their owners. Nine of the dogs showed similar neural activation for both the praise stimulus and the food stimulus. And two of the dogs consistently showed more activation when shown the stimulus for food.

Berns says the findings run counter to the old view that dogs “just want food and their owners are simply the means to get it … Another, more current, view of their behavior is that dogs value human contact in and of itself.”

In another part of the study, dogs were put into a Y-shaped maze in which one path led to a bowl of food and the other path to the dog’s owner.

The dogs were repeatedly released into the room and allowed to choose one of the paths.

While most dogs alternated between the food and their owner, dogs who showed a greater response to praise in the first part of experiment chose to go to their owners 80 to 90 percent of the time.

Berns said the study “shows the importance of social reward and praise to dogs. It may be analogous to how we humans feel when someone praises us.”

ozziefood

(Photos: At top, Kady, a Lab-retriever mix in the study who preferred praise from her owner to food; at bottom, Ozzie, a shorthaired terrier mix who chose food over his owner’s praise / Emory University)

Is the quality of dog semen declining? And are contaminants in dog food to blame?


Researchers at the University of Nottingham say they’ve documented a serious decline in the fertility of male dogs — and suggest that dog food or environmental causes may be to blame.

In a study spanning 26 years, researchers tracked the sperm motility levels of five different breeds — Labrador retrievers, golden retrievers, curly coat retrievers, border collies and German shepherds.

They took samples from between 42 and 97 dogs each year, according to the study, published in Scientific Reports.

Between 1988 and 1998, the team recorded a 2.5 percent decline in the amount of motile sperm per year. Between 2002 and 2014, this trend continued at a rate of 1.2 percent each year.

The researchers also found that male pups produced by dogs with declining sperm quality had an increased incidence of cryptorchidism, a condition where one or both of the testicles don’t descend properly.

The study suggests that the sperm quality may have been impacted by contaminants in dog food.

“We looked at other factors which may also play a part, for example, some genetic conditions do have an impact on fertility,” said Dr Richard Lea, leader of the study. “However, we discounted that because 26 years is simply too rapid a decline to be associated with a genetic problem.”

Dogs used for the study were all bred, raised and trained as service animals for disabled people at an unidentified center in England, according to the New York Times.

The scientists said that in addition to collecting samples throughout the study, they examined the testicles collected from dogs that had undergone castration.

Both showed environmental contaminants in high enough concentrations to affect sperm motility. These same chemicals were also discovered in various commercially available dog foods.

The researchers say the findings raise the question of whether a reported decline in human semen quality over the last 70 years could also be a result of environmental factors.

(Photos: Roscoe, a yellow Lab who was not involved in the study, and has no interest in the results, by John Woestendiek)