Tag Archives: evolution

Women influenced co-evolution of dogs and humans

Man’s best friend might actually belong to a woman.

Photo by Wade Austin Ellis

In a cross-cultural analysis, Washington State University researchers found several factors may have played a role in building the mutually beneficial relationship between humans and dogs, including temperature, hunting and surprisingly—gender.

“We found that dogs’ relationships with women might have had a greater impact on the dog-human bond than relationships with men,” said Jaime Chambers, a WSU anthropology Ph.D. student and first author on the paper published in the Journal of Ethnobiology. “Humans were more likely to regard dogs as a type of person if the dogs had a special relationship with women. They were more likely to be included in family life, treated as subjects of affection and generally, people had greater regard for them.”

While dogs are the oldest, most widespread domesticated animal, very few anthropologic studies have directly focused on the human relationship with canines. Yet when the WSU researchers searched the extensive collection of ethnographic documents in the Human Relations Area Files database, they found thousands of mentions of dogs.

Ultimately, they located data from more than 844 ethnographers writing on 144 traditional, subsistence-level societies from all over the globe. Looking at these cultures can provide insight into how the dog-human relationship developed, Chambers said.

“Our modern society is like a blip in the timeline of human history,” she said. “The truth is that human-dog relationships have not looked like they do in Western industrialized societies for most of human history, and looking at traditional societies can offer a wider vision.”

The researchers noted specific instances that showed dogs’ utility, or usefulness, to humans, and humans’ utility to dogs as well as the “personhood” of dogs—when canines were treated like people, such as being given names, allowed to sleep in the same beds or mourned when they died.

A pattern emerged that showed when women were more involved with dogs, the humans’ utility to dogs went up, as did the dogs’ personhood.

Another prevalent trend involved the environment: the warmer the overall climate, the less useful dogs tended to be to humans.

“Relative to humans, dogs are really not particularly energy efficient,” said Robert Quinlan, WSU anthropology professor and corresponding author on the paper. “Their body temperature is higher than humans, and just a bit of exercise can make them overheat on a hot day. We saw this trend that they had less utility to humans in warmer environments.”

Quinlan noted there were some exceptions to this with a few dog-loving cultures in the tropics, but it was a fairly consistent trend.

Hunting also seemed to strengthen the dog-human connection. In cultures that hunted with dogs, they were more valued by their human partners: they were higher in the measures of dogs’ utility to humans and in personhood. Those values declined, however, when food production increased whether it was growing crops or keeping livestock. This finding seemed to go against the commonly held perception of herding dogs working in concert with humans, but Quinlan noted that in many cultures, herding dogs often work alone whereas hunting requires a more intense cooperation.

This study adds evidence to the evolutionary theory that dogs and humans chose each other, rather than the older theory that humans intentionally sought out wolf pups to raise on their own. Either way, there have been clear benefits for the dogs, Chambers said.

“Dogs are everywhere humans are,” she said. “If we think that dogs are successful as a species if there are lots of them, then they have been able to thrive. They have hitched themselves to us and followed us all over the world. It’s been a very successful relationship.”

Source: Washington State University

Study of ancient dog DNA traces canine diversity to the Ice Age

A global study of ancient dog DNA, led by scientists at the Francis Crick Institute, University of Oxford, University of Vienna and archaeologists from more than 10 countries, presents evidence that there were different types of dogs more than 11,000 years ago in the period immediately following the Ice Age.

In their study, published in Science, the research team sequenced ancient DNA from 27 dogs, some of which lived up to nearly 11,000 years ago, across Europe, the Near East and Siberia.* They found that by this point in history, just after the Ice Age and before any other animal had been domesticated, there were already at least five different types of dog with distinct genetic ancestries. 

This finding reveals that the diversity observed between dogs in different parts of the world today originated when all humans were still hunters and gatherers.

Photo by E.E. Antipina

Pontus Skoglund, author and group leader of the Crick’s Ancient Genomics laboratory, says: “Some of the variation you see between dogs walking down the street today originated in the Ice Age. By the end of this period, dogs were already widespread across the northern hemisphere.”

This study of ancient genomics involves extracting and analysing DNA from skeletal material. It provides a window into the past, allowing researchers to uncover evolutionary changes that occurred many thousands of years ago.

The team showed that over the last 10,000 years, these early dog lineages mixed and moved to give rise to the dogs we know today. For example, early European dogs were initially diverse, appearing to originate from two highly distinct populations, one related to Near Eastern dogs and another to Siberian dogs. However, at some point this diversity was lost, as it is not present in European dogs today.

Anders Bergström, lead author and post-doctoral researcher in the Ancient Genomics laboratory at the Crick, says: “If we look back more than four or five thousand years ago, we can see that Europe was a very diverse place when it came to dogs. Although the European dogs we see today come in such an extraordinary array of shapes and forms, genetically they derive from only a very narrow subset of the diversity that used to exist.” 

The researchers also compared the evolution in dog history to changes in human evolution, lifestyles and migrations. In many cases comparable changes took place, likely reflecting how humans would bring their dogs with them as they migrated across the world.

But there are also cases when human and dog histories do not mirror each other. For example, the loss of diversity that existed in dogs in early Europe was caused by the spread of a single dog ancestry that replaced other populations. This dramatic event is not mirrored in human populations, and it remains to be determined what caused this turnover in European dog ancestry. 

Greger Larson, author and Director of the Palaeogenomics and Bio-Archaeology Research Network at the University of Oxford, says: “Dogs are our oldest and closest animal partner. Using DNA from ancient dogs is showing us just how far back our shared history goes and will ultimately help us understand when and where this deep relationship began.”

Ron Pinhasi, author and group leader at the University of Vienna, says: “Just as ancient DNA has revolutionised the study of our own ancestors, it’s now starting to do the same for dogs and other domesticated animals. Studying our animal companions adds another layer to our understanding of human history.”  

While this study provides major new insights into the early history of dog populations and their relationships with humans and each other, many questions still remain. In particular, research teams are still trying to uncover where and in which human cultural context, dogs were first domesticated. 

*The researchers sequenced ancient DNA from 27 dogs. Their analysis also included previously sequenced genomic data from a further 5 dogs.

Source: The Francis Crick Institute

The evolution of puppy dog eyes

Dogs have evolved new muscles around the eyes to better communicate with humans. New research comparing the anatomy and behavior of dogs and wolves suggests dogs’ facial anatomy has changed over thousands of years specifically to allow them to better communicate with humans.

Puppy dog eyes

In the first detailed analysis comparing the anatomy and behavior of dogs and wolves, researchers found that the facial musculature of both species was similar, except above the eyes. Dogs have a small muscle, which allows them to intensely raise their inner eyebrow, which wolves do not.

The authors suggest that the inner eyebrow raising movement triggers a nurturing response in humans because it makes the dogs’ eyes appear larger, more infant like and also resembles a movement humans produce when they are sad.

The research team, led by comparative psychologist Dr Juliane Kaminski, at the University of Portsmouth, included a team of behavioural and anatomical experts in the UK and USA.

It is published in PNAS (Proceedings of the National Academy of Sciences).

Dr Kaminski said: “The evidence is compelling that dogs developed a muscle to raise the inner eyebrow after they were domesticated from wolves.

“We also studied dogs’ and wolves’ behavior, and when exposed to a human for two minutes, dogs raised their inner eyebrows more and at higher intensities than wolves.

“The findings suggest that expressive eyebrows in dogs may be a result of humans unconscious preferences that influenced selection during domestication. When dogs make the movement, it seems to elicit a strong desire in humans to look after them. This would give dogs, that move their eyebrows more, a selection advantage over others and reinforce the ‘puppy dog eyes’ trait for future generations.”

Dr Kaminski’s previous research showed dogs moved their eyebrows significantly more when humans were looking at them compared to when they were not looking at them.

She said: “The AU101 movement is significant in the human-dog bond because it might elicit a caring response from humans but also might create the illusion of human-like communication.”

Lead anatomist Professor Anne Burrows, at Duquesne University, Pittsburgh, USA, co-author of the paper, said: “To determine whether this eyebrow movement is a result of evolution, we compared the facial anatomy and behaviour of these two species and found the muscle that allows for the eyebrow raise in dogs was, in wolves, a scant, irregular cluster of fibres.

“The raised inner eyebrow movement in dogs is driven by a muscle which doesn’t consistently exist in their closest living relative, the wolf.

“This is a striking difference for species separated only 33,000 years ago and we think that the remarkably fast facial muscular changes can be directly linked to dogs’ enhanced social interaction with humans.”

Dr Kaminski and co-author, evolutionary psychologist Professor Bridget Waller, also at the University of Portsmouth, previously mapped the facial muscular structure of dogs, naming the movement responsible for a raised inner eyebrow the Action Unit (AU) 101.

Professor Waller said: “This movement makes a dogs’ eyes appear larger, giving them a childlike appearance. It could also mimic the facial movement humans make when they’re sad.

“Our findings show how important faces can be in capturing our attention, and how powerful facial expression can be in social interaction.”

Co-author and anatomist Adam Hartstone-Rose, at North Carolina State University, USA, said: “These muscles are so thin that you can literally see through them – and yet the movement that they allow seems to have such a powerful effect that it appears to have been under substantial evolutionary pressure. It is really remarkable that these simple differences in facial expression may have helped define the relationship between early dogs and humans.”

Co-author Rui Diogo, an anatomist at Howard University, Washington DC, USA, said: “I must admit that I was surprised to see the results myself because the gross anatomy of muscles is normally very slow to change in evolution, and this happened very fast indeed, in just some dozens of thousands of years.”

Soft tissue, including muscle, doesn’t tend to survive in the fossil record, making the study of this type of evolution harder.

The only dog species in the study that did not have the muscle was the Siberian husky, which is among more ancient dog breeds.

An alternative reason for the human-dog bond could be that humans have a preference for other individuals which have whites in the eye and that intense AU 101 movements exposes the white part of the dogs eyes.

It is not known why or precisely when humans first brought wolves in from the cold and the evolution from wolf to dog began, but this research helps us understand some of the likely mechanisms underlying dog domestication.

Source:  University of Portsmouth

Dogs’ brains respond to human voices

Yet more research on how dogs’ brains work.  This time from a research team at Eötvös Loránd University in Hungary and published in the journal Current Biology.

Using functional MRI, the team could see where blood flowed in the brains of a group of 11 dogs.  The dogs had been specially trained using positive reinforcement techniques to lie still in the MRI scanner for six minutes.

A dog lies still in the fMRI scanner, wearing earphones to pipe in sounds as part of the study. (Photo by Eniko Kubinyi)

A dog lies still in the fMRI scanner, wearing earphones to pipe in sounds as part of the study. (Photo by Eniko Kubinyi)

which tracks blood flow to various areas of the brain, a sign of increased activity—to peer inside the minds of dogs. One of a handful of labs groups worldwide that’s using the technology in this way, they’ve used positive reinforcement training to get a study group of 11 dogs to voluntarily enter the fMRI scanner and stay perfectly still for minutes at a tRead more: http://www.smithsonianmag.com/science-nature/your-dog-can-tell-from-your-voice-if-youre-happy-or-sad-180949807/#DXcpTX0jfeQGFWVY.99
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The team played each dog a series of over 200 sounds across several MRI sessions.  The sounds included human voices, dog vocalizations, and meaningless noises.

When the results were compared, it showed that the dogs’ brains appear to have a dedicated area that displays more activity in response to voices (whether human speech or dogs barking) than other meaningless noises (such as glass breaking).

More importantly, that part of the brain shows more activity upon hearing an emotionally positive sound, as compared to a negative one.  This means that our dogs are able to distinguish a tone of voice that is positive from one that is negative. (Something many of us probably already knew)

The voice areas of the dogs’ brains is similar to that found in humans, suggesting that our species evolved from a common ancestor almost 100 million years ago, enabling a high degree of communication and social structure.

“We know that dogs don’t have language, per se, but we see now that dogs have very similar mechanisms to process social information as humans,” Attila Andics, lead researcher on the study says. “It makes us wonder what aspects of so-called ‘language skills’ are not so human-specific after all, but are also there in other species. That’s something we plan to look at.”

Source:  Smithsonian Magazine

Here are my earlier blogs about functional MRI studies on dogs:

they show that the dogs’ brains appear to have a dedicated area that displays more activity in response to voices (whether human speech or dogs barking) than other meaningless noises (such as glass breaking), and that part of this area shows more activity upon hearing an emotionally positive sound, as compared to a negative one.Read more: http://www.smithsonianmag.com/science-nature/your-dog-can-tell-from-your-voice-if-youre-happy-or-sad-180949807/#DXcpTX0jfeQGFWVY.99
Give the gift of Smithsonian magazine for only $12! http://bit.ly/1cGUiGv
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Adapting to the high altitudes of Tibet

In a new study published in the journal Molecular Biology and Evolution, author Dong-Dong Wu, et. al., explored the genetic basis of high-altitude adaptation of Tibetan Mastiffs, which were originally domesticated from the Chinese native dogs of the plains.

Credit: © zuzule / Fotolia

Credit: © zuzule / Fotolia

The authors examined genome-wide mutations (called single nucleotide polymorphisms, or SNPs) of 32 Tibetan Mastiffs, and compared them to 20 Chinese native dogs and 14 grey wolves. Overall, they identified more than 120,000 SNPs, and in their analysis, narrowed these down to 16 genes that have undergone positive selection in mastiffs, with 12 of these relevant to high altitude adaption.

These candidate genes have been shown to be involved in energy production critical to high-altitude survival under low oxygen conditions.

For future studies, the authors will explore whole genome sequences from individual Tibetan Mastiffs to gain better insights into high-altitude adaptations and canine evolution.

Source:  EurekAlert! media statement

Doing the dog paddle

If you have ever watched your dog swim, you’ve probably noticed that intense look of concentration on their face.  Research has confirmed that swimming doesn’t come as naturally as, say,  walking, running or trotting on land.

Photo by the Society for Integrative and Comparative Biology

Photo by the Society for Integrative and Comparative Biology

Dr. Frank Fish, a professor of biology at West Chester University, set out with his colleagues to understand how real dogs perform the dog paddle.

Dr Fish found a large horse rehabilitation pool for filming eight dogs of six different breeds during swimming.  Dr Fish’s own dog was one of the study subjects.

The team analyzed the videos and found that the dogs were swimming with a gait that was similar to a familiar trot on land. When a dog trots, moving at a pace more brisk than a walk, diagonal pairs of legs move together. In swimming, the dog’s legs move in a similar fashion, but even faster than a trot, and the legs move beyond the range of motion for a trot.  (This is one reason why I recommend swimming for many – but not all – of my massage and rehab customers.)

Swimming dogs are, essentially, using a basic movement but with some modification. Also, while the movements that make up terrestrial gaits like trotting can vary from one dog breed to another, the dog paddle gait showed very little variation among the different breeds.

Dr Fish says that dogs can be used as a model for precursors to early swimming mammals.   He hopes to unravel the steps in evolution that allowed four-legged terrestrial animals to become swimming mammals like the dolphin.

In the meantime, get out there and let your dog swim.   For most dogs, it’s great exercise!

Daisy concentrates during her swim at the Dog Swim Spa

Daisy concentrates during her swim at the Dog Swim Spa

Want to know more about physical rehabilitation and whether swimming is right for your dog?  Get in touch with me by completing the information below.

Kathleen Crisley, specialist in dog massage, rehabilitation and nutrition, Canine Catering Ltd, Christchurch, New Zealand

Source:  Society for Integrative and Comparative Biology media release

The ancestral roots of your dog

A genetic study by Peter Savolainen, a researcher in evolutionary genetics at KTH Royal Institute of Technology in Stockholm, has found that dog breeds from North and South America have Asian ancestry.

The Chihuahua definitely has Mexican heritage

The Chihuahua definitely has Mexican heritage

The native breeds have 30 percent or less modern replacement by European dogs.  It had been thought, prior to this study, that when Europeans settled in the American continent their dog breeds successively replaced the genetics of the native breeds.

Savolainen’s research group, in cooperation with colleagues in Portugal, compared mitochondrial DNA from Asian and European dogs, ancient American archaeological samples, and American dog breeds, including Chihuahuas, Peruvian hairless dogs and Arctic sled dogs.

They traced the American dogs’ ancestry back to East Asian and Siberian dogs, and also found direct relations between ancient American dogs and modern breeds.

The research confirmed conclusively that the modern day Chihuahua has Mexican roots.  The breed shares a DNA type uniquely with Mexican pre-Columbian samples.

The team also analysed stray dogs, confirming them generally to be runaway European dogs; but in Mexico and Bolivia they identified populations with high proportions of indigenous ancestry.

Source:  AlphaGalileo Foundation news release

Dog intelligence

Most dog owners have an opinion about their dog’s intelligence.  I regularly hear comments like, “He’s so smart, he’s ahead of the rest of his obedience class” or “He’s not very bright, but we love him.”

 When I was working on my management qualification years ago, we were told to go home and ask our partner/flatmate about how they solved problems.  Ebony, my Labrador flatmate at the time, came up with these tips, which I thought were very intelligent:

  1. Remember that chasing your tail does not get you anywhere.  It also makes you dizzy and less able to focus on the task at hand.
  2. Eat regularly and often.  Problem solving is hard work and requires energy.
  3. Don’t underestimate the value of a nap.  A problem looks different after you’ve had a good sleep.
  4. If you stare at a problem long enough, it might move on its own.
  5. Don’t be afraid to ask for help.  Try looking cute.
  6. If looking cute doesn’t work, try whining.
  7. If whining fails, loud retching noises are guaranteed to get the attention of those around you.
  8. Some problems soften over time.  Burying them in the garden hastens this process.
  9. Some problems require more immediate attention.  An immediate problem, if left unattended, is likely to result in a much more smelly mess to be cleaned up later.

There are many published works on the subject of dog intelligence.  Over the years, I’ve read countless research studies into this subject.  There are many institutions involved in the research.  All projects have the goal of understanding how dogs think.

Professor Stanley Coren of the University of British Columbia has authored several books about dog intelligence.  He states that dogs have the intellectual capacity of a two-year old and can understand more than 150 words.[1]

Researchers at the Max Planck Institute for Evolutionary Anthropology have studied the ability of dogs to interpret human gestures.  When researchers hid food beneath one container in a group and pointed to the ‘right’ container, dogs consistently picked up on those cues better than even chimpanzees (a species widely studied because of the evolutionary link between apes and humans).

Earlier this year, a research team at the University of Otago reported on their study that showed that dogs could readily distinguish happy human sounds from sad or angry ones, suggesting an ability to understand human emotions.

Even the dog toy market has recognised that dogs need mental stimulation.  The Nina Ottosson range, for example, offers a range of skill level toys designed to make your dog think about how to reveal their food reward.

Daisy demonstrates her intelligence with a Nina Ottosson toy

Despite all of this evidence, including videos of my Daisy using her interactive toys, many of the non-dog people in my life remain unconvinced about the intelligence of dogs.  I believe that persistence will pay off.  Over time we will see more and more research about the intellectual capacity of our dogs.  The non-believers will become believers.


[1] Science Daily, 10 August 2009