In Defence of Dogs

by John Bradshaw

  Nowhere is this more obvious than in the dog’s apparent obsession with depositing small quantities of urine as scent-marks. Male dogs are renowned for their routine raised-leg urinations, but females also urine-mark routinely: although they usually squat to urinate, many also use a ‘squat-raise’ marking posture. It is not entirely clear why females leave scent-marks; one clue may be found in the observation that bitches in Indian villages squat-raise around their lairs. The male dogs in the same villages perform their characteristic ‘raised-leg urination’ everywhere, but especially at the boundaries of their family-group territories.11 Male wolves, particularly breeding males, also mark at territorial boundaries and along frequently used paths, presumably as a way of communicating with other packs nearby.

  The domestic dog’s passion for ‘pee-mail’ can therefore be traced back through its immediate ancestor, but this does not explain why pet dogs do it so enthusiastically today. Perhaps they would like to ‘own’ the area where their owners take them for exercise; however, because they have to share this with other dogs and their access is time-limited by their owner, they get caught up in a vicious cycle. Every time they go out, they find that the scent-marks they left yesterday have been overmarked by other dogs. So they have to mark again to re-establish their claim to ownership, and so on and so on.

  ‘Squat-raise’ urine-marking

  Scientists still do not know precisely what message is contained in each urine-mark, but it seems highly likely that dogs’ urine carries an odour that is unique to each individual, one that can be memorized by others. It is also likely that in male dogs this unique odour contains contributions from the preputial gland as well as from the urine itself. What is less clear is how much other information is conveyed. For example, can a dog tell how large, how old, how hungry, how anxious, how confident another dog is, simply by sniffing its scent-mark? We cannot yet answer this question, but we do know that the main message carried by a bitch’s urine, apart from her identity, comes from the vaginally produced scents that indicate the status of her reproductive cycle. Bitches that are willing to mate produce a powerful pheromone that can attract males from long distances. (Pheromones are chemical signals which are similar in all individuals of a species.)

  However, scent does have one serious flaw as a communication medium, namely, that the message itself is very hard to control. Mammalian scent-signals are mainly produced by specialized skin glands (though they may be deposited mixed with normal body fluids or wastes – faeces or urine or saliva). These glands inevitably get invaded by micro-organisms; these alter the scent by adding metabolic products of their own, which can be pungent. If you had a nose as sensitive as a dog’s, it would be like putting up a notice in front of your house where graffiti artists come along at unpredictable times and progressively alter whatever is on the sign, including obliterating your own name.

  Some animals, dogs included, have handed over responsibility for producing the smell to the micro-organisms themselves. For example, bacteria on the mother’s skin make the odour that newborn puppies use to orientate towards their mothers. Likewise, the anal glands of both male and female dogs (and many other carnivores) secrete a mixture of fats and proteins into the anal sacs to which they are attached, allowing the bugs to turn these into the more volatile chemicals that make up the odour itself. (Scientists have shown that if antibiotics are injected into the sacs, killing the micro-organisms, the secretion becomes almost odourless.) The ‘graffiti artists’ can now write what they like, but they can use only the ‘colours’ (fats and proteins) they are given, and thus the dog retains an element of control.

  Such an odour is, however, both arbitrary and ever-fluctuating, placing limits on its usefulness. It is impossible to predict what it will smell like in advance, and if it is to be of any use in transmitting information, recipients will first have to learn what it means, and then relearn whenever it changes. Scent-marks that are intended to claim ownership of territory present an additional problem, since their whole point is that they should permanently identify individuals who are absent. If the odour of an owner’s scent-mark changes from one week to the next, an intruder may mistakenly deduce that ownership of the territory has recently changed when in fact it has not.

  A territory-holder can overcome this drawback by occasionally actually meeting his neighbours, thereby giving them the opportunity to make the connection between his appearance and his scent. If that scent is changing subtly over time, then those meetings need to be frequent enough for the connection to be maintained. This behaviour is known as ‘scent-matching’; widespread in rodents and in antelope, it is less widely studied in carnivores, and not at all in dogs, despite there being every indication that they must be doing something like it.

  Making and reinforcing the link between odour and appearance seems to be uppermost in many dogs’ minds whenever they meet, suggesting that they do engage in a kind of scent-matching. It is likely that they memorize the odours of all the dogs they meet (why else go to the trouble of all that sniffing?) and then compare these with all the more indirect information that they get from sniffing scent-marks while they are out on walks – a kind of ‘scent-matching’. If they do not find any match, then they may assume that the other dog lives far away; if they find a lot of matches, then the dog must live nearby. Since scent-matching is usually connected with territorial behaviour, perhaps domestic dogs perceive public parks and streets as a vast ‘no man’s land’ between territories, always worth checking for occupancy in case they ever get the chance to live there.

  Left to their own devices, many dogs prefer to use their sense of smell even when vision would appear to be more efficient. Trained explosives-search dogs always prefer to use their noses rather than their eyes, even in circumstances where visual cues might lead them to their target more quickly. However, dogs are also very flexible in their behaviour, and pet dogs quickly come to realize that we humans are much more attuned to visual than to olfactory cues. As a result, dogs can be successfully fooled into choosing an empty bowl rather than a bowl full of food, simply by having their owners point to the empty one.12 Normally, of course, the dogs could have quickly identified the full bowl from its smell. This exemplifies the high priority that dogs put on social information, and also how well adapted they are to attending to the ways we, as well as they, communicate.

  Moreover, since dogs can tell each other apart by smell, they can surely learn the characteristic odours of the humans they live with or meet on a regular basis. They can probably also tell a great deal about our moods from the way these odour cues vary. Dogs can be specially trained to alert epileptic or unstable diabetic owners when they are about to have a seizure or hypoglycaemic attack. There is little doubt that they do this by reacting to changes in the owner’s odour (although minute changes in ‘body-language’, undetectable to human observers, may also be part of the cue). Even ordinary pet dogs can be trained to perform this service; no special olfactory ability seems to be necessary.13 The implication is that all dogs are at least potentially able to monitor our moods based on the way our body odour changes. (Of course, they must simultaneously allow for, and possibly try to interpret, other causes of our changing odour, such as our state of health and the different foods that we have eaten.) If so, they are picking up, and presumably reacting to, a vast range of information about our lives that we ourselves are only dimly aware of.

  Perhaps one reason why we can be so oblivious to the importance our dogs place on smell is how little they seem to suffer as a result of our ignorance. However, just as their ears can be damaged by the high levels of ultrasound produced by the clanging of metal kennel gates and furniture, dogs’ noses must surely be insulted by what must seem to them to be the overpowering odours of our detergents, fabric softeners and ‘room fragrances’. Presumably they just get used to them, accepting them as an unavoidable downside of sharing a living space with the humans they are so closely bonded to. In the hygiene-conscious world we live in,
many of us do not like to let dogs do what they must feel compelled to do when they first meet us, which is to sniff us. I always hold out my hand to any dog I am introduced to (I make a loose fist first, in case the dog has a habit of nipping fingers). If the dog wants to lick my hand as well as sniff it, I let him. Not doing so would be as unsociable as hiding our face from someone we are being introduced to, and I can always wash my hand later if I want to.

  Perhaps it is just as well that we have only recently started to become aware of this ‘secret world’ that dogs inhabit; otherwise we might have been tempted to interfere with it. We have certainly taken liberties with their visual communication, by breeding them into such diverse shapes and sizes. The potential for a Chihuahua and a Great Dane to misunderstand each other’s visual signals seems almost unlimited, since they do not look like one another, nor indeed does either look much like a wolf. However, their scent glands, and the behaviour that enables them to use these to communicate effectively, seem for all intents and purposes to be intact. It is quite possible that dogs’ reliance on scent has been their salvation, enabling even breeds that look extraordinarily different from one another to go on conversing with one another – at some rather basic, smelly level.

  10

  Problems with Pedigrees

  Throughout most of this book, I have discussed dogs as if they were all roughly equivalent. For our purposes, this is very often true; despite some inevitable variations between breeds, all dogs share an evolutionary past, an acute sense of smell, a capacity for forming strong bonds with people and an ability to recognize one another as members of the same species and to interact with one another accordingly. However, dogs are self-evidently not all the same, and sometimes it is the differences between them that most affect their well-being. The differences between dogs are primarily imposed by us, not by the dogs themselves. Where mankind does not interfere with breeding, dogs look much the same; village dogs in Africa, for instance, are essentially similar. They evolve into a type that is adapted to the environment they find themselves in. When humans start to choose which dogs to breed from, however, they generate dogs who are, by definition, less well suited to that niche. Initially, this probably did not matter at all. The capabilities that equip dogs to live on the street, alongside mankind, have gradually been replaced by those that allow dogs to live with man. These include not only changes that enable dogs to earn their living, such as helping with herding, hunting and guarding (to name but three), but also those that enable dogs to be good companions.

  Changes in the rates of development of the basic wolf blueprint have led to today’s extremes of size and shape

  However, as this process continued, there must have been many dogs whose well-being was compromised by humankind’s attempts to produce more extreme forms. For example, the Romans bred their mastiffs larger and larger, striving for fiercer and fiercer dogs. Some of these dogs must have been freaks – puppies too large to pass through their mother’s pelvis, or dogs whose skeletons were too heavy for their joints and thus in constant pain. In those rough-and-ready days, with precious little veterinary care, a crude kind of natural selection would have prevailed. Dogs that were not viable would have been stillborn or would not have lived long enough to breed, and dogs too infirm to perform their intended task would not have been selected for breeding.

  Like all animals, dogs are capable of producing far more offspring than is necessary for the continuation of their species. Unless a population is growing rapidly, this inevitably means that many individuals die before reproducing. As a general rule, those that die first are those least well suited to their environment. Many will have suffered before they died. This of course applies as much to village dogs as it does to dogs being bred by man for specific purposes. Nevertheless, the creation of new forms of dog inevitably left casualties in its wake.

  Times have changed. In the West, we now believe in the right of each individual dog not to suffer. Puppies are no longer regarded as disposable items, to be drowned if unwanted. There is an outcry in the media whenever any cull of dogs is proposed, whether these be ferals, strays or unwanted pets. These are high standards indeed. We have taken upon ourselves the obligation to ensure that every puppy is a wanted puppy and will grow to be a healthy, happy dog. In many ways, we have succeeded in fulfilling these responsibilities. We have developed sufficient veterinary care to enable the majority of dogs to lead healthy lives. High-quality nutrition specifically designed for dogs is available in every supermarket, to the point that many have a healthier diet than some humans.

  In other ways, however, we have failed our canine companions. In our seemingly insatiable quest for novelty, we have bred dogs which suffer from a vast range of avoidable ailments. And in our anthropomorphic need to see dogs as extensions of our own personalities, we have generated dogs that are unacceptably aggressive or have other temperamental defects. Their role as companions – a role they must fill if they are to be assured of leading physically and psychologically healthy lives – seems rarely to be the first priority. Novice owners can be faced with choosing between pedigree puppies, primarily bred for appearance rather than temperament, and rescue dogs of uncertain parentage, some of which may have been abandoned because they are the progeny of dogs bred for aggression.

  Whereas dogs once made their own decisions about reproduction, nowadays in the West most matings are planned by humans. Over the past hundred years specialists have increasingly come to control dog breeding. At present, most of our pet dogs are either pedigree dogs or can trace their ancestry just a few generations back to crosses between pedigree animals. By comparison with the whole history of the domestic dog, this is a very recent phenomenon, and one that is geographically and culturally confined: genuinely ancient types of dog persist in many parts of the world. Nevertheless, most of the dogs available as pets to Westerners have pedigree ancestors.

  The current rules for breeding pedigree dogs are causing profound and accelerating harm to their genetic viability. The current registration systems for pedigree dogs in the United Kingdom and many other parts of the world confine each breed to mating only with other members of the same breed. If this system were to be imposed totally, it would result in each breed becoming completely genetically isolated from all other dogs (in actuality, due to unplanned matings and occasional deliberate cross-breeding, only the pedigree breeds have been sequestered in this way).

  Although most of these breeding regulations are very new – affecting only the most recent 1 per cent of the whole evolutionary history of the dog – they are already having profound effects on the dogs we see today. The genetic isolation of each breed has brought about a dramatic change in the dog’s gene pool, massively reducing the amount of variation in each breed. The less the variation, the more likely it is that damaging mutations will affect the welfare of individual dogs: in order for a potentially detrimental mutation to actually cause harm, it generally has to have been present in both parents – and this is likely to occur only if the parents themselves are closely related. In some dog breeds today it is difficult to find two parents that are not closely related.

  Until very recently, the amount of variation in the domestic dog was sufficient to maintain genetic health. Multiple domestications and back-crossing with wolves have meant that dogs worldwide still have an estimated 95 per cent of the variation that was present in the wolves during the time of domestication. Most of this variation lives on today in street dogs and mongrels, but pedigree dogs have lost a further 35 per cent. That may not seem much, but let us imagine the scenario in human terms. Mongrels maintain levels of variability that are similar to those found globally in our own species. In many individual breeds, however, the amount of variation within the whole breed amounts to little more than is typical of first cousins in our own species. And we humans know that repeated marriages between cousins eventually lead to the emergence of a wide range of genetic abnormalities, which is why marriages between close relatives are taboo
in most societies. It is astonishing that the same consideration has not been given to dogs.

  Just a handful of prize-winning popular sires are used to father the majority of puppies. This has tremendously restricted the gene pool. For example, about 8,000 new golden retrievers are registered in the United Kingdom each year, with a total population of perhaps 100,000. Over just the last six generations inbreeding has removed more than 90 per cent of the variation that once characterized the breed.1 In a recent sampling of the Y (male) chromosomes of dogs in California, no variation at all was found in fifteen out of fifty breeds, indicating that most of the male ancestors of each and every dog in those breeds had been close relatives of each other.2 Some of the other breeds surveyed had only a very little variation. In the context of the imported breeds in the study, such as the Rhodesian ridgeback, the boxer, the golden retriever, the Yorkshire terrier, the chow-chow, the borzoi and the English springer spaniel, this is not surprising. Assuming that all Californian examples are likely to have descended from a small founder population, limited gene pools are to be expected: much more variability might have been apparent if the samples had been taken in other countries. Of more concern was the lack of variation in the three American breeds in the study, since these are more likely to be representative of those breeds worldwide. There was no variability at all in the fifteen Boston terriers tested, and only a small amount in the twenty-six American cocker spaniels and ten Newfoundlands. Conversely, a couple of breeds recently derived from street dogs, the Africanis (or Bantu dog), and the Canaan dog, showed levels of variation similar to those in mongrels, but this can be ascribed to a deliberate policy among their breeders, who have seen the problems that popular sires have brought to other breeds of minority interest.