Dog Behavior Blog

What To Do With A Pulling Dog

Training your dog not to pull on a leash is a common goal for many dog owners. Pulling can be uncomfortable for the owner and make walks unpleasant. In a pulling contest, the dog usually wins. But with patience and consistency, you can teach your dog to walk calmly on a leash.

Here are some steps you can follow to train your dog not to pull on a leash:

1. Use the right equipment: Choose a comfortable, properly fitting harness and a leash that is the right length for your dog's size. For most dogs, a 6 foot leash usually works well. Pick a leash that is comfortable for your hand and comfortable for the dog.
2. Start with rewards: Reinforce good behavior by giving your dog treats and praise when he is walking calmly on a leash. Praise usually works better than treats, because with treats, dogs can sometimes learn to refuse to do anything unless they receive a treat.
3. Avoid pulling: If your dog begins to pull, stop walking and stand still until she calms down and comes back to you. Then continue walking and reward your dog for walking calmly.
4. Practice: Consistent training is the key to success. Practice short walks several times a day, gradually increasing the length of the walks as your dog improves.
5. Change direction: If your dog begins to pull, change direction abruptly. This will disrupt the pulling behavior and encourage your dog to pay attention to you.
6. Incorporate commands: Teach your dog to respond to commands like "heel" or "come." Use these commands during walks to help redirect your dog's focus to you and encourage good behavior.
7. Be patient: Training takes time and patience. It's important to avoid punishment and stay positive and encouraging during the training process.

With consistency and patience, you can teach your dog to walk calmly on a leash. This will make walks more enjoyable for both you and your dog friend. Remember, positive reinforcement and consistency are key to success.

 

Ethology Nobel Laureate Konrad Lorenz

As this year’s Nobel Prizes were announced, I faced my annual wish for anyone interested in dog training and behavior to know that three scientists in the field of Ethology have been awarded this prize. In 1973, Niko Tinbergen (The Netherlands), Karl von Frisch (Austria), and Konrad Lorenz (Austria) were awarded the Nobel Prize in Physiology or Medicine “for their discoveries concerning organization and elicitation of individual and social behaviour patterns.” They are regarded as being among the founders of the field of Ethology, which is the study of animals in their natural habitat.

While they are best known for their work with birds, insects, and fish, all of them studied a variety of species. Konrad Lorenz was quite interested in dogs, and wrote a wonderful book called Man Meets Dog. One of the great contributions of this book to the study of animals concerns Lorenz’ interdisciplinary approach to understanding dogs. As Donald McCaig states in the introduction to a recent edition, “He made it respectable to bring the practical observations of animals trainers and handlers into the academy. It was a great first step, and although the gulf between academic study and practical applications remains with us today, Lorenz did much to merge what is known from different areas into a cohesive body of knowledge in order to further our understanding of animals.

(photo: Konrad Lorenz, Eurobas, wikipedia.org)

Some of my favorite aspects of this book are personal stories. For example, Lorenz describes the close relationship between his future brother-in-law, Peter, and a Newfoundland named Lord who joined the family when the dog was 1½ years old. Peter was the smallest of four brothers, and the youngest in a gang of boys who participated in their fair share of mischief. The dog protected him to such a degree that even his schoolmaster dared not raise his voice to Peter, lest he growl and leap up with his massive size on the shoulders. Naturally, this dog kept the other boys from teasing or bullying him as well.

Lorenz discusses his great sadness at losing dogs to old age. When he was 17, his dog Bully died of a stroke and he describes his sadness that the dog had left no offspring. For a long time after Bully’s death, Lorenz says he heard the pattering of Bully’s peculiar gait following after him as he had done for so many years in life. He writes, “If I listened consciously, the trotting and snuffling ceased at once, but as soon as my thoughts began to wander again I seemed to hear them once more.” Only when his new puppy Tito began to run behind him and follow him everywhere did the “ghost” of Bully cease to follow him in his mind.

Years later when Tito died, Lorenz felt a great guilt knowing that another dog would take the place of Tito just as Tito had replaced Bully in his heart. He says he felt ashamed of his own unfaithfulness and decided that for the rest of his life, only descendents of Tito would be his companions.

--Karen London

 

Toys That Dogs Like

My Standard Poodle Raja loves to play "ball." In his case, "ball" is anything that he can chase, catch, and bring back to the person throwing the "ball." Although he will do this with round balls that he can fit into his mouth, he really prefers plush toys that look like chipmunks or rabbits, that are small enough for him to fit into his mouth, and that squeak when he chews on them.

The downside of his playing "ball" is that he needs to convince some willing person to play this game with him.

What about dogs who don't have a person around? What sort of toys do they like to play with?

When I tried to find some scientific articles that have looked at this, I found that few had studied this problem.

However, a recent article in the scientific literature investigated what sorts of toys dogs in kennels like to play with (Pullen, A J et al. 2010. Preferences for toy types and presentations in kennel housed dogs. Applied Animal Behaviour Science 125: 151-156).

The experimenters studied the kinds of toys that dogs liked to play with in two different types of kennels:

· Re-homing kennels (the equivalent of Humane shelters), where dogs are brought in off the street for adoption.

· Long-term kennels where dogs spend most of their lives in a kennel.

The circumstances of kennel life were very different between the two types of kennels. In the re-homing kennels, the environment was very new to most dogs and the dogs showed signs of stress at being in unfamiliar surroundings. In the long-term kennels, the dogs were used to being in the kennels and received a lot of enrichment in the form of off-leash walks and interactions with people in an enclosed environment.

The experimenters gave both groups of dogs two types of toys to play with, and recorded the amount of play on video:

· One type was robust toys, which were difficult for the dog to destroy. These included a large indestructible ball, a rope tug knotted at both ends, a nylon and rubber flexible tug toy, and a rubber frame toy.

· The other type was less robust and easier for the dogs to damage. These included a vinyl bone with a squeaker, a soft fabric toy with two squeakers, a plush toy with a squeaker, and a tennis ball.

The robust toys were presented to the dogs as either hanging toys, suspended by a metal chain into the middle of the kennel, or as floor toys, placed onto the floor of the kennel.

The less-robust toys were only placed on the kennel floor.

Although there were some differences between the responses of the dogs in the re-homing kennels and the dogs in the long-term kennels, there was a common thread:

· The dogs generally did not like to play with toys that were hanging.

· The dogs preferred the soft squeaky toys to the hard indestructible ones.

While the indestructible toys are more attractive to people because dogs can't shred them, the indestructible toys are less attractive to dogs.

However, dogs can destroy the soft squeaky toys and possibly swallow pieces of the toy or the squeaker.

That means that if you give soft squeaky toys to your dogs, you have to watch them to make sure that they don't swallow anything.

I'm sure that Raja would agree with the results of this experiment. The only thing that they left out, in his opinion I am sure, are the people who can throw the soft squeaky toys for him to retrieve.

--Con Slobodchikoff

 

Why Dogs Eat Grass

These summer days, when I take my Standard Poodle Raja for a walk, he always wants to stop and eat grass. Not just any grass. The leaves have to be the right size and shape. Although there are other grasses nearby, he always heads for wheatgrass (Agropyron), with its broad green leaves.

I have read that dogs eat grass because they want to vomit or because they are having digestive troubles.

Raja hates to vomit. He will do anything to keep from vomiting, so that doesn't seem to be the answer, at least as far as he is concerned.

I feed him premium wet food, and he digests it very well, with well-formed stools (I get to sample these on walks, picking them up with my plastic bags). Digestive troubles do not seem to apply to Raja either.

So because the two explanations I have read do not seem to be relevant to Raja, I decided to dig a little bit into the scientific dog literature to see what I could find.

Surprisingly little has been written in scientific journals about why dogs eat grass.

One recent study approached grass eating in dogs with the hypothesis that grass alleviates digestive distress (McKenzie et al. 2010. Reduction in grass eating behaviours in the domestic dog, Canis familiaris, in response to mild gastrointestinal disturbance. Applied Animal Behaviour Science 123: 51-55).

In that study, the authors fed dogs a diet that produced loose, watery stools, to mimic a condition of a mild digestive upset. They also fed the dogs a standard diet that produced normal stools, and gave the dogs two types of grasses to eat during each experimental condition.

The results were that the dogs ate more grass when they were fed a standard diet than when they ate the diet that caused the digestive upset. So much for that hypothesis.

Then there's vomiting.

I found a study that looked at whether dogs vomit more when they eat grass (Sueda et al. 2008. Characterisation of plant eating in dogs. Applied Animal Behaviour Science 111: 120-132),

In that study, the authors surveyed 1571 dog owners on the internet and found that 79 percent of the dogs ate grass, and of these, only 9 percent were sick before they ate the grass, and 22 percent vomited after eating the grass.

These results show that the vomiting hypothesis doesn't seem to hold any water either.

So why do dogs eat grass?

Ask yourself that question the next time you eat a luscious salad.

My guess is......because it tastes good.

--Con Slobodchikoff

Puppies Get Socialized By Watching TV

My Standard Poodle Raja has no interest in watching TV. Dogs could be cavorting and barking across the screen, and he could care less. Even closeups of dog faces produce no results. If I try to call his attention to something that I think might interest him, he will sleepily open an eye out of politeness and then promptly go back to sleep on the couch in front of the tube.

I have always assumed that this is because dogs see TV screens differently from us. The typical screen flickers at 50-60 cycles per second (Hertz for the technically-minded), which is adequate for our eye to fuse it into a solid picture (again, for the technically-minded, the flicker-fusion-frequency). Dogs, on the other hand, fuse flickers into solid pictures at around 70-80 cycles per second, far above the flicker of the TV screen. Instead of a solid picture, they must see a whole bunch of flickers.

However, a recent study has found that puppies that are 3 to 5 weeks old can see a TV screen and respond to the objects that they are seeing on the TV (Pluijmakers et al. 2010. Exposure to video images between 3 to 5 weeks of age decreases neophobia in domestic dogs. Applied Animal Behaviour Science 126: 51-58). The study played back both sounds and sights of people, dogs, traffic, and objects such as vacuum cleaners, in an 8 minute video clip that was played to the puppies each day for 2 weeks from the time the puppies were 3 weeks old until they were 5 weeks old.

The study found that puppies who were exposed to different images and objects on the TV screen at that early age were much less fearful of strange situations by the time they were 8 weeks old. This is a critical time for puppies, when they are learning about the world around them, and what they learn during this time stays with them for the rest of their lives.

And fearfulness can affect a dog's lifespan. Another recent study found that fearful dogs had a significantly shorter lifespan than more confident dogs, probably as a result of constant stress (Dreschel, N. A. 2010. The effects of fear and anxiety on health and lifespan in pet dogs. Applied Animal Behaviour Science 125: 157-162).

So why is my Raja so uninterested in watching the TV, if 3 week-old puppies can see what is happening on the screen? The short answer is, I don't know. But a longer answer might be that he probably was never exposed to the TV as a puppy, and never got used to watching. He came to us as an adult rescue dog, and I have no idea what his early background was.

Chances are, by the time he saw a TV screen, it was already too late for him to make any sense out of it.

Sometimes, I think he has a point.

--Con Slobodchikoff

Is Dominance A Useful Concept In Dog Behavior?

Is dominance a useful concept in dog behavior?  In the past, much of our thoughts about dominance in dogs came from captive wolf populations where there was a linear dominance hierarchy, with an alpha wolf who was most dominant, then a beta wolf who was dominant over everyone except the alpha, and so on down the line, until we got to the omega wolf who was dominant over no one.

When wild wolves were studied, the concept of dominance in wolves became much looser, because wild wolf social groups are either family units or extended family units (parents, young, and siblings of parents), and adult wolves tend to assume more dominant positions over the younger wolves, but otherwise the situation is fairly fluid. (See the March 19, 2010 post on this blog by Dr. Suzanne Hetts on dominance myths, and the YouTube video by Dr. L. David Mech on wolf dominance at: http://www.youtube.com/watch?v=tNtFgdwTsbU).

But our training methods of dogs go back to the concepts of dominance derived from captive wolf groups.

 Some of our training methods assume that we have to be physically dominant over our dogs. This involves in extreme cases the alpha roll, or rolling the dog over on his back and standing over him (something that I personally do not recommend, as it is a way to get bitten and possibly traumatize everyone concerned, including the dog).  Other methods involve pushing the dog down for a "sit" or a "down" command, and yanking a dog around on a leash.

Non-physical methods include giving dogs less priority of access to resources such as food or space.  For example, a dog might be required to wait before getting food, or might be expected to tolerate having her food bowl taken away by her people half-way through her dinner without her showing any signs of aggression.

But dogs are not wolves, even though genetically they share more than 99 percent of their genes with wolves.

And because dogs have been domesticated for a long time, it is hard to get humans out of the equation and find out what is normal for social groups of dogs when they are not interacting with people.

Surprisingly few studies have looked at the social interactions within dog packs that have not been associated with people.

A recent study looked at dominance interactions in a free-ranging social group of dogs that had relatively little contact with humans in the suburbs of Rome, Italy (Cafazzo, S. et al. 2010. Dominance in relation to age, sex, and competitive contexts in a group of domestic dogs. Behavioral Ecology 21: 443-455).

The dog social group had 27-40 dogs, and was observed for a total of 15 months. During that time, the composition of the group changed by some dogs leaving, others joining the social group, some dogs dying, and some pups being born to females.   The authors of the study present their results based on observations of 6 adult males, 5 adult females, 1 subadult female, 4 subadult males, 5 juvenile females and 6 juvenile males, or 27 dogs in all.

The authors characterized dominance interactions as two kinds: agonistic dominance, and formal dominance. They defined agonistic dominance as situations where one dog acts aggressively and the other dog acts submissively. They defined formal dominance as situations where one dog gives another dog a submissive signal without the first dog showing any aggression.  They studied dominance interactions under the following conditions:  1) when there were no resources for the dogs to compete; 2) when the dogs had to compete over food; 2) when the male dogs had to compete over receptive females.

The bottom line in this study is that dominant status did not always correlate well with aggression.  The aggressive dogs were not necessarily the most dominant in terms of submission of other dogs when there was no competition for food or females. 

Dominant status did correlate well with the formal dominance described by the authors, where one dog produced signals that another dog responded to with submission.  Such formal dominance gave dogs priority of access to food when they were competing, and gave some males priority of access to receptive females.

So what does this study mean for us?

One take-home message is that you don't need to be aggressive with your dog for her to acknowledge that you are more dominant (or at least, for you to have higher status than your dog).  All you need to do is have the right kind of signals that your dog understands. In other words you have to learn to communicate with your dog rather than beat her into submission.

Another take-home message is that despite our long association with dogs, we still don't really know how they think.  We know what dominance means to us, but we are still struggling to find out what it means to dogs, and whether our idea of dominance is even a meaningful concept for our furry friends.

--Con Slobodchikoff

Get Your Signals Straight In Obedience Training

When I work with training people and their dogs, I find that it is sometimes a challenge to get people to say just the command. If I ask people to tell their dog to "Sit," some people might say, "Please Sit," others might say the dog's name and the command, "Rover, Sit," and still others keep repeating the command like travelers in a foreign land dealing with people who don't speak their language.

While learning theory suggests that saying the command once and not saying anything else is the most effective way to train a dog, there has really been very little practical evidence to substantiate this.

A recent study provides a field and an experimental test of how well dogs respond to commands if their name or something else precedes the command (Braem and Mills. 2010. Factors affecting response of dogs to obedience instruction: A field and experimental study. Applied Animal Behaviour Science 125 (2010): 47-55).

In the field study, the authors videotaped 56 dog handlers giving their dog a "Sit" command.  There was a roughly equal mix of male and female dogs that were used, of a variety of breeds, and the handlers ranged in age from 10 to 60-plus.  The authors found that two factors influenced the dogs' performance in obeying the command: the attention that the dog gave to the handler while the handler was giving the command, and the amount of verbal information that the handler spoke before giving the command. Both of these factors decreased the performance of the "Sit" command.

In the experimental study, the authors used 12 dogs of various breeds, with only one handler who was always dressed the same and acted the same when giving the commands.  The handler taught to the dogs to respond reliably to a known command (e.g., "Down"), and to a novel command ("uff" to signal jumping up on a platform where there was a reward).

Then the authors did a series of experiments where each dog was given one of several combinations of commands:   the dog's name, followed by a one-second pause, then either the known command or the new command; and an unknown word (the German "Banane") preceding either the known or the new command.

The authors found that saying the unknown word before either the known or the new command significantly decreased the dogs' performance.  Saying the dog's name prior to the known command ("Down") had no effect on performance, but saying the dog's name prior to the new command ("uff") decreased the dogs' performance, just like saying the unknown word before a command.

So the results of this study substantiate the predictions of learning theory. Saying just the command is better than saying anything else along with it, although saying the dog's name does not seem to have any effect, as long as the dog is very familiar with the command.

 Saying "Rover, won't you be a good dog and sit down, pretty please?" just doesn't cut it in training dogs to respond to a command.

--Con Slobodchikoff

Dog Dominance Is A Very Complicated Issue

My Standard Poodle Raja likes to lead. When we come to a door, he likes to go in first. He also likes to jump in first into the car, and on walks he likes to be out in front, ahead of any of us. On walks, he would walk ahead of our other Standard Poodle, Zephyr.  By some interpretations, this would make him the dominant dog of the pack.

But things aren't that simple. Raja will also happily lie down at the drop of a hat and present his belly to be rubbed. He would also go up to Zephyr and lick Zephyr's muzzle while wagging his tail, which is kept down. Zephyr on the other hand would stand with his head and his tail up, accepting Raja's licking. This should mean that Raja is submissive to both us and to Zephyr.

So which is it? According to some interpretations, dominant dogs are the ones who want to go first, who have priority of access to everything, and who never show submissive behavior. For many years, a standard way of teaching dogs to not show dominance behavior was to make them wait at doorways until the people have gone through first, to make them wait at food bowls, and to make them wait at car doors so that their people would have priority of access. This was supposed to instill the idea that the people were more dominant than the dog.

Our ideas of dominance in dogs came initially from studies of captive wolf packs in zoo-like settings, where the wolves set up linear hierarchies with one or two dominant animals at the top and all of the rest of the wolves being progressively less and less dominant, depending on where they fit on that linear hierarchy.

Studies of wild wolves have failed to confirm that wolves have linear dominance hierarchies.  Wild wolf packs tend to be family groups, and the two parents tend to be dominant in much the same way that human parents tend to be dominant over their kids. They loosely set the rules, and the kids sort things out among themselves. (See a previous post on the Dog Behavior Blog by Dr. Suzanne Hetts, who discusses some of the myths of dominance and some of the work of Dr. L. David Mech with wild wolf pack behavior).

A recent study of free-ranging dogs in Italy addresses the leadership question in the light of dog dominance (Bonanni et al. 2010. Effect of affiliative and agonistic relationships on leadership behaviour in free-ranging dogs. Animal Behaviour 79: 981-991). The authors studied two packs of free-ranging dogs on a nature preserve in the suburbs of Rome. They found that one of the two packs, with 27 members, had very fluid leadership, with 6 dogs habitually leading the pack, but at least half of the adult dogs were  leaders some of the time. The habitual leaders tended to be the older, more experienced dogs, but not necessarily the most dominant.  

Leadership issues were even more complicated in the other pack, which was smaller with 9 dogs. This pack had one consistent leader for a month, a male who was previously a member of the larger pack but was not a habitual leader there. However, this male left the pack after one month, at which point a female became a habitual leader, although other dogs led as well. This female also came originally from the larger pack, where she was not a habitual leader.  A habitual leader of the larger pack joined this smaller pack part-way through the study, but did not become a habitual leader in his new pack.

As an aside, the authors define two types of dominance in dogs: formal dominance and agonistic dominance. Formal dominance is when a submissive dog comes up to a dominant one and licks the dominant's muzzle while keeping his tail low and wagging it. This is what Raja would do with Zephyr. Agonistic dominance is when a submissive dog would respond to a threat signal from a more dominant one by crouching down, pressing his tail down, or rolling over on his back. This is what Raja would do with us, although we never threatened him.

What the study of the free-ranging dogs shows is that dominance is a complicated issue in dogs, and cannot be reduced down to simplistic things like going through doors first or being out in front in a leadership role.

The other thing that this study shows is that dominance is not something that dogs are born with, but something that they might acquire depending on their situation.  Perhaps some dogs are genetically predisposed to be more dominant, but that does not mean that they will necessarily be dominant in any particular situation.  This is why some people prefer the term "status" to the term "dominance" when describing dominance interactions in dogs.

The third important point of this study is that dominance does not mean threats and aggression. The authors found that the dogs who used agonistic dominance, threat signals that elicited submissive behavior such as yelps or tails pressed low in other dogs, were seldom leaders.  Dogs who accepted signals of formal dominance, muzzle licking and wagging tails without any threats or aggression, were much more likely to be leaders.

As we study dogs in more natural settings, we are finding that dog behavior is much more complicated than we once assumed.

--Con Slobodchikoff

The Dog Bark Controversy

Are dog barks just meaningless sounds designed to get attention? Or do the barks contain information that other dogs can use about the context of the bark or the identity of the caller?

Two articles have been published recently that address this controversy. One article says that barking contains no information, but is a way of dogs grabbing attention for the purpose of mobbing, a cooperative behavior that is used by a variety of animals to repel potential predators (Lord et al. 2009. Barking and mobbing. Behavioural Processes 81:358 -- 368). The other article says that dogs can incorporate information about the context of the bark and the identity of the individual dog who is barking (Molnar et al. 2009. Dogs discriminate between barks: The effect of context and identity of the caller. Behavioral Processes 82:198 -- 201).

The article by Lord et al. presents a lot of the acoustic characteristics of dog barks and says that these acoustic characteristics are similar to the kinds of signals produced by birds and other mammals when they are mobbing a predator. Typically these calls have a raspy sound to them, have a lot of noise, and generally sound very harsh to our ears. On the basis of this kind of similarity, the authors suggest that there is no meaning incorporated into the calls. This follows the theories of Raymond Coppinger (one of the authors of the Lord et al. article), who has argued that dog barks have no meaning beyond conveying excitement or general arousal.

The article by Molnar et al. approaches this problem by doing experiments. The authors collected barks from five Mudi dogs, Hungarian sheepdogs. The barks occurred in two behavioral contexts: when the dogs were barking for a stranger, and when the dogs were barking because they were left alone. Then they used another group of 30 dogs in a technique called habituation -- dishabituation. In this technique a dog is played back a sequence of three barks for the same context, and then played back a bark for a different context. The experimenters assess how much time the dog spends looking at the speaker for each of the playbacks of the barks. If the dog cannot detect any difference between the sequence of the first three barks and the last bark, the dog should spend a shorter and shorter amount of time looking at the speaker after each playback, by habituating to the barks. If on the other hand the dog can recognize the difference between the first three playbacks and the last one, where the last one is a bark from a different context, then the dog would spend more time looking at the speaker after the fourth playback than it did looking at the speaker after the third playback.

This is exactly what the authors of the study found. Also, when they played back a sequence of barks recorded from the same individual dog, and then a bark from a different individual dog in the same context, the dogs listened more to the bark of the different dog, suggesting that they can tell the differences between barks from different dogs for the same context.

The Molnar et al. study follows up on an earlier study by Yin and McCowan in 2004 where those authors  analyzed the acoustic structure of dog barks in three different contexts: a stranger ringing a doorbell, a dog who is isolated from her owner, and a play situation where two dogs were a dog and human are playing together. The statistical analysis of the acoustic structure of the different calls showed that the calls could be grouped into different contexts, and also that the calls from individual dogs could be identified (Yin, S. and B. McCowan. 2004. Barking in domestic dogs: context specificity and individual identification. Animal Behaviour 68: 343-355).

The two studies, Molnar et al. and Yin and McCowan, support each other in their findings. The Molnar et al. study provides experimental proof that dogs behaviorally can detect the differences between contexts and between individual dogs. The Yin and McCowan study shows that there are distinct acoustic differences between dog barks for different contexts, and also between dog barks from different individuals.

This gives increasing support to the idea that dogs can incorporate meaningful information into their calls. It also suggests that when one dog is barking, another dog can probably know who that dog is, just the same way that we can identify someone by their voice, even if we only hear them on the telephone.

-- Con Slobodchikoff

Can The Shape Of A Dog’s Head Tell Us Anything About Trainability?

In 1994 Dr. Stanley Coren wrote a landmark book, The Intelligence of Dogs, where he sampled the opinions of a large number of obedience judges on the trainability of different breeds of dogs (see Dr. Coren’s blog post from June 10, 2009 on our blog here).  Dr. Coren identified the breeds that were most and those that were least trainable, and related this to the relative intelligence of the different dog breeds, at least as far as their general trainability went.

A recent article (Helton, W. F. 2009. Cephalic Index and Perceived Dog Trainability. Behavioural Processes 82:355-358) attempts to connect the shape of dogs’ heads to their trainability. By looking at the ratio of the width to the length of the skull (a cephalic index), dogs can be categorized as dolichocephalic (having a short skull width with respect to the length, as in Greyhounds), mesocephalic (having a medium width of the skull with respect to the length, as in Poodles), and brachycephalic (having a large skull width with respect to the length, as in Staffordshire Bull Terriers).

These groups of dogs differ in their morphological specializations. Dolichocephalic dogs are specialized for running, while brachycephalic dogs are more specialized for fighting.

Interestingly, the eye morphology of the two types of dogs differs. Brachycephalic dogs like the Staffordshire Bull Terrier have a lot of the retinal ganglions concentrated in a central area, like the human fovea, allowing them to focus better on single objects, such as other dogs they might need to fight. Dolichocephalic dogs like the Greyhound are like wolves in their retinal morphology. They have a visual streak of retinal ganglia, distributed like a line across the retina, allowing them to best see moving objects such as prey on the horizon rather than focus in detail on single objects. (for details, see McGreevy, P. et al. 2004. A strong correlation exists between the distribution of retinal ganglion cells and nose length in the dog. Brain, Behavior and Evolution 63: 13-22; DOI: 10.1159/000073756).

Curiously enough, the Helton article in Behavioural Processes finds that the breeds that are the most trainable are those that fit into the mesocephalic category, with neither a very long or a very short nose, and a skull width that is intermediate between narrow and wide. This includes breeds such as the Border Collie, Poodle, Labrador Retriever, and Golden Retriever.

What isn’t clear to me is why this should be so. The author of the article speculates that the mesocephalic brain shape represents a compromise between a brain adapted for running and a brain adapted for fighting. So, if this is true, then maybe the breeds in the other categories are so specialized that they don’t need to learn to do new things. They either run or they fight. But the dogs in the middle can’t run as fast and can’t fight as hard, so maybe they have to be more flexible in learning how to get by in the world.

And as long as I am speculating, let me take this a little bit further. If there really is a relationship between the shape of the skull and trainability, maybe we can use this as a way of predicting the trainability of mixed breeds.  When we look at shelter dogs of mixed parentage where it isn’t obvious which breed contributed the most to the genetic makeup of the dog, maybe we can get an idea of how easy the dog is going to be to train from the shape of the skull.

In my book, all dogs are wonderful. Some just require more work than others. If we can predict how much work might have to go into training a mixed-breed dog, maybe there won’t be as many dogs returned at shelters.

--Con Slobodchikoff

 

Dog Breeds And Genetic Relatedness

Although by now most people accept that dogs and wolves are closely related genetically, a question still remains about which breeds are most related to wolves and to other breeds.  A recent study published in Nature magazine (vonHoldt, B. M. et al. 2010, Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication, Nature 464 (8 April 2010): 898-903 DOI: 10.1038/nature08837) has examined this question.

The  experimenters used a technique called Single Nucleotide Polymorphisms(SNPs) to study the genetic relationships among samples from 912 dogs representing 85 breeds, as well as samples from 225 grey wolves from 11 different geographic areas around the world.

I was surprised to see that wolves from the Middle East contributed a significant portion of genetic variation to most of the modern dog breeds.  Of the dog breeds that were examined, the Basenji had the highest genetic relatedness to Middle Eastern wolves.  Other breeds that were more closely related to wolves included the Akita, Chow Chow, Dingo, Shar-Pei, Alaskan Malamute, Siberian Husky, Afghan Hound, Saluki, American Eskimo, and Samoyed.

Breeds that had higher genetic relatedness with European wolves included Greyhounds, Whippets, Miniature Pinschers, and Staffordshire Bull Terriers.  The Akita and Chow Chow had higher relatedness with Chinese wolves, as might be expected.

Also as could be expected, Old World wolves had higher genetic relatedness to dog breeds than New World wolves, suggesting that domestication of dogs took place in Europe, the Middle East, or Asia, rather than in North America.

Some of the genetic relationships between the breeds surprised me. For example:

·         the Chihuahua was relatively closely related genetically to the Pomeranian and the American Eskimo,

·         the Papillon was relatively closely related to the Pug, Brussels Griffon, Shih-tzu, and Pekinese,

·         the Portugese Water Dog was relatively closely related to the German Shepherd,  Standard Schnauzer, Giant Schnauzer, and Doberman Pincher

·         the Newfoundland was closely related to the  Labrador, Flat-Coated Retriever and Golden Retriever,

·         the Rhodesian Ridgeback was relatively closely related to the Great Dane and Rottweiler. 

 

These relationships suggest that our conventional categories of dogs (e.g., Working Dogs, Herding Dogs, etc.) are groupings that we make for our convenience, rather than groupings that reflect the relatedness of the different breeds.

One thing, however, does not surprise me: We humans are pretty good at coming up with different breeds of dogs.

--Con Slobodchikoff