Some Sociobiological Aspects
of Canine Reproduction

by Pernille Monberg
first appeared in IW World, Volume II, July 2006

A common feature in all fields of animal husbandry appears to be a rather clinical approach to reproduction. Natural selection has largely been exchanged with a selection based on human logic and desires. For more than 12,000 years, man has shaped and altered natural species into a vast selection of domestic animals, whose sole purpose has been to serve the needs of those who molded them. This is an ever-ongoing process, where each mating is based on manmade choices, which rarely take sociobiological aspects of reproduction into consideration. In spite of an effective domestication process, man's choices may still go wrong from time to time; a planned mating between individuals, thought to be perfect matches, may fail either to mate or to produce progeny.

In the following, I would like to propose that there might be perfectly logical explanations therefore. Claimed fertility problems in many kennels may not necessarily have anything to do with the feed or water, or be caused by poor reproductive health. According to reproduction specialist and veterinarian Birgitte Schjøth, a very common reason for dogs' failure to reproduce is poor management on behalf of the owner. Other theories bring forth a possibility of an instinctual avoidance of genetic incompatibility, which individuals can detect through the smell of the other dog's pheromones. I would like to add that a bit of insight and understanding of dog behavior can be very helpful toward a successful breeding program.


My empirical data is based in large part on personal observations accumulated during 30 years of living with a pack of Irish Wolfhounds. The hypotheses presented below are supported by similar observations made by other dog breeders. A more systematic quantitative data collection would be needed, however, in order to fully validate the observations from a scientific point of view.

A Perspective

If the assumption is that there might not be a greater deity with an overall intent or purpose in life, then what drives us? Looking at the myriad of life forms inhabiting the planet earth, the all-encompassing common denominator appears to be a drive to reproduce. This drive is so strong that in some species, once reproduction is successfully completed, the individuals die -- seemingly with no further purpose once the genetic matter has been passed on. In many species, the mother will fight until death to protect her young. Salmon take on a long journey upstream to their breeding grounds, and die off once their spawning has been completed. In the world of insects, some female spiders kill their mates after copulation, and among the praying mantises, the female has to kill the male to enable him to ejaculate while mating -- thus securing the passing on of genes with the sacrifice of life.

Social Structure of the Pack Formed Around the Right to Reproduce

Complex social structures have emerged in many species to secure reproduction. Frequently, only two leading individuals in the group hold this right; the rest of the members are merely workers, whose sole purpose is to secure the future of the progeny of the leaders. As in many other species, the canid packs largely consist of family members, thus it is tempting to conclude that there is a common interest in nurturing and protecting progeny of shared genetic material. In a domestic pack of dogs, the human interference decides the composition of the group. However, if allowed, natural behavioral patterns will nevertheless emerge in varying degrees.

The Social Order

A yearling bitch coming of age is firmly reminded of her inferior position by older bitches.
A yearling bitch coming of age is firmly reminded of her inferior position by older bitches.

In my pack, there has always been a clear division of areas of control and responsibility between the sexes. The males have to look after their right to reproduce; in other words, an alpha male is primarily preoccupied with keeping younger males under control. There usually isn't a graduated hierarchy among the males. There is the alpha and his subjects. The alpha does not accept conflicts among the other males, which might lead to a rank or order among them. Even the slightest squabble among inferior males is clamped down upon immediately. It appears that the self-esteem in the inferior males is to be kept down in order to secure peace in the pack -- and to prevent them from reproducing.

Leadership is not as clear-cut among the bitches, even though there is a matriarch in my pack; it is more like a three-generation female family group which rules collectively. Squabbles among the females within the close female family are usually left to be sorted out among the parties. These conflicts are rarely of lasting or serious nature, but a conflict between a member of the matriarch group and one of the "outsiders" almost inevitably turns into a mass brawl if uninterrupted by human caretakers.

Strategies Ensuring Social Order and Reproductive Rights

Conflicts are not an everyday occurrence, but are awakened during events like a bitch in estrus. This affects the entire pack, from the smallest puppies to the spayed elders. If a low-ranking bitch is in season, this means that she and all the males are to be kept under strict control so she doesn't conceive and produce offspring. The other females constantly harass the bitch in estrus and the males are stressed and distracted in every possible way.

Nine-year-old matriarch, Saragh, flirting with a young visiting male.
Nine-year-old matriarch, Saragh, flirting with a young visiting male.

An old matriarch will do anything to attract the attention of the males if another bitch has come in estrus. She will go through all the motions of teasing and playing, and after a few days she will apparently start secreting attractive odors, which has the males constantly sniffing and following her around. Should one of the males pay too much attention to the bitch in season, then any member of the three-generation matriarch family will firmly break it up. Human planning and interference prevents the scene being played out to the end. Males and a bitch in estrus are usually separated before she is ready to receive.

During times of non-estrus, the senior bitch will still ruffle the youngest males, first thing every morning when spirits are high. It is obvious that they want to play, but have a profound respect for the matriarch as well, and end upside-down on the ground showing their submission.

Nine-year-old matriarch, Saragh, getting on her back encouraging the slightly intimidated young male to play.
Nine-year-old matriarch, Saragh, getting on her back encouraging the slightly intimidated young male to play.

The youngest (even pre-puberty) pack members are affected by these situations. They sense the stress and sometimes feel the effects of getting too close to the short-fused adults. Normally pre-puberty youngsters enjoy endless freedom; they are no threat to the reproduction hierarchy of the pack. They are merely taught the basics of good dog behavior and left to enjoy themselves. As soon as they approach puberty, they are perceived as potential threats to the social order. They are then harshly disciplined by the elders to ensure low self-esteem, so their reproductive potential is easier to control.

Juveniles in a pack can go through a long period of depression, as well as show signs of anxiety in all aspects of life. For the dog owner, it is a fine balance between not protecting the youngsters too much in relation to the elders, and at the same time teaching them to gradually differentiate between respecting and fearing the pack elders by observing the rules -- all the while encouraging them to take on the rest of domestic life in an open and positive manner. This is a lot to ask of our dogs, but a major part of the domestication process has turned them into something resembling bi-cultural beings.

Synchronized Seasons and the Purpose of False Pregnancies

Frequently vets and dog owners perceive and treat the commonly seen phenomenon of pseudo pregnancies as if it were a pathological condition, when in reality it is a very important aspect of natural pack survival. Anyone owning several female dogs will experience a tendency for these bitches to synchronize their estrus. There are several possible explanations for this, one being competition for the right to reproduce within the group.

Leadership and social structure are ever-challenged, even in well-functioning packs. If an inferior bitch comes in season, the matriarch or one of her cohorts will frequently come in as well if they are close anyway, just to ensure their right to reproduce. My senior matriarch will willingly receive a male for a period of up to two weeks, which is far beyond the biological requirement for her to conceive. I have always interpreted this as her trying to cover as much time as possible, in order to control the male attention.

There is another very practical explanation for the synchronized seasons of bitches, and later pseudo pregnancies: The matriarch has many willing babysitters for her puppies if the inferior bitches are in a similar hormonal state as she, who has just whelped a litter.

Failure to Conceive and Resorbing of Litters

In recent years, it has become a more common practice to use ultrasound scans to determine pregnancy in dogs. With this practice, we have also learned that it isn't uncommon for bitches who have been confirmed pregnant to fail to produce litters on the due date. What is happening here is that for one reason or other fetuses die off (usually between weeks 3-6) and are resorbed without further ado. The bitch does not abort and rarely becomes ill from the ordeal.

This could be described as a form of biological altruism, yet not much is written about the phenomenon. When reading through stacks of veterinary articles, explanations cover a whole series of pathological conditions in the reproductive organs, though virtually none takes social factors into consideration. Dr. Liss-Marie Langborg, chief veterinarian specializing in reproduction and diseases of the reproductive organs at Sweden's Strömsholms Regional Animal Hospital, acknowledges that pack dynamics can prevent a bitch from becoming pregnant. "A high-ranking bitch can signal to a lower-ranking bitch that she may not become pregnant. Look at wolf packs where only the alpha bitch has the right to reproduce," she says (cited in Hundsport Special, 2. 2005 p. 27).

We also have examples from other mammals who live in family groups such as the highly social large rodents, marmots. Among these the alpha female fiercely protects her sole right to reproduce, and will beat her daughters into aborting, should they have become pregnant. The juvenile and adult daughters have an important part in raising their mother's successive litters. The application of various forms of stress to inferior pack members is an important and frequently used tool to gain and maintain control. Stress does not only prevent bitches from becoming pregnant; applied stress to an already-pregnant bitch will force her to resorb her litter.

An Important Lesson

In my pack, I have an extremely dominant bitch, the eldest daughter of the matriarch. The daughter is probably not completely convinced of her status, so she feels that she constantly has to assert herself. Her favorite victims are a Swedish-bred bitch and her daughter, whom we call "the immigrants." The immigrant mother came to us at the age of 1.5 years, and was never really perceived as a full-fledged member of the pack. Only through her sublime communication skills and proper dog behavior has she avoided ever being in actual physical confrontations.

I have concluded that due to her mother's position, the daughter is also attributed a lower status. The immigrant bitch did have one litter three years ago, but since then, we have been unable to get her to conceive, or rather carry a pregnancy to the end. At one point, she contracted a pyometra, which was successfully treated chemically. She was then mated through three consecutive seasons, but failed to conceive at least twice, and we know that she resorbed a litter once.

Her daughter was mated for the first time at the age of 2.5 years; she was ultrasounded and confirmed pregnant, but failed to produce puppies. I was getting increasingly frustrated with the situation. By chance I talked with a man in the fur-fox industry, who told me that the fur farmers have many problems with bitches resorbing their litters. One of the solutions offered was to remove very dominant bitches from the premises, which apparently helped the problem somewhat.

My vet, also a breeder of Old English Sheepdogs, told me that one of her bitches would ruffle the others at least once daily, and that as a result another bitch failed to produce puppies in several attempts to get her in whelp. Finally, the breeder placed the very dominant bitch in a home, and immediately her problematic bitch conceived and carried a litter to term.

I then tried observing my pack with this perspective in mind, and it became very clear that the junior matriarch was constantly harassing these two immigrant bitches. She would never leave them alone, constantly walking by their side, with her head and tail held high. The immigrants tried to avoid her gracefully but were stressed by her; they seemed depressed and did not want to go out when they saw her outside.

I decided to have the junior matriarch spayed, which brought about an almost immediate change in the dynamics of the pack. The junior matriarch pretty much stopped harassing the other bitches, and I observed a drastic change in the two immigrants. Their moods changed within weeks after the dominant bitch was spayed; they appeared to be much happier and not intimidated by her at all.

About six months later, I succeeded to get the immigrant bitch, who had missed three times, in whelp. Inspired by the assumed results of my strategy, I had the daughter inseminated with frozen semen. Just to make sure that none of the high-ranking bitches had a chance of stressing her into resorbtion of the litter, she has been completely isolated from them, as I did with her mother. The strategy seems to have worked; she was due to deliver in a few weeks at this writing.

Do Dogs Have Preferences in Partners?

As breeders, we seem to believe that animals possess somewhat raw, primordial sex drives, enabling them to mate anyone, anywhere, anytime at our command. I remember countless times where a bitch owner has traveled over long distances to mate a bitch with one of my males, only to realize that either the bitch or the dog refuses to mate. After ruling out the obvious, such as poor timing (with progesterone readings), or possible antibiotic treatment of the bitch, which alters her scent, I have often been left dumbfounded with no immediate explanation.

Ebony Saragh of Nutstown one month short of her 9th birthday
Nine-year-old matriarch, Saragh, flirting with a young visiting male.

However, I recall that our stallions also seemed to have preferences among the mares, so why rule out that dogs should have their preferences as well? Our eldest stud dog has had a sufficient number of bitches to show that he clearly likes some better than others. In fact, he has flatly refused to mate some bitches, whilst others enjoyed his immediate attraction.

According to one of Sweden's leading geneticists, professor in genetics and animal husbandry Per-Erik Sundered, there are some very sensible reasons for individuals to prefer some partners to others. He says that they are able to smell in the pheromones released if they are genetically compatible.

Survival of a species is best secured by genetic diversity, a point greatly missed by most dog breeders. Per-Erik Sundgren notes that genetic diversity ensures immune systems that are more effective and that animals, including humans, can smell which sexual partner to select based on indirect information on the individual's genetic diversity. Studies have shown that the opposite sexes are inevitably attracted to partners with the most diverse genetic make-up, which also happens to differ the most from their own.

Sundgren says that forced matings are an effective way of destroying nature's own protective mechanism of selecting the healthiest breeding combinations.

When Visitors Bring Bitches in for Matings

Finally, it is important to understand what we subject our bitches to when we travel with them to have them mated. We bring them to kennels which have a number of dogs, and expect them to unquestioningly walk in and accept the male. The odors of the resident dogs immediately tell her that she is entering a foreign territory inhabited by strangers with their own social order -- of which she isn't a part.

With no rank or low rank, she should not even have a right to mate or reproduce, and she is aware of this. Therefore, when we have bitches come in for mating, we prefer that the owners and their dogs do not stay with us. We also make sure that all mating takes place outside the fence of the property, in an attempt not to upset senior males if one of the younger males has a visitor. It is also an attempt to let the younger male understand that this is an extraordinary situation, which only can take place away from the rest of the pack.

Mother/Son Incest Avoidance

The first time I was ever presented with the phenomenon of mother/son incest avoidance in dogs was in The Hidden Life of Dogs by anthropologist Elizabeth Marshall Thomas. The author observed that the incest avoidance was only effective between a mother and her resident sons. The bitch seemed to relate differently to sons and non-resident sons, when they came for occasional visits.

As an exception to that tendency, one of my bitches was taken to Sweden for a mating. One of her adult sons also lived at the kennel where the male of our choice resided. She was extremely inviting towards the older male, but when she met her own son, whom she hadn't seen since he was a puppy, she launched at him with an unmistakable growl when he started making flirty whimpers and postures at her through the fence. She definitely remembered him.

I also had a Jack Russell Terrier who could be left together with her son all through her season -- had I dared. He was allowed to court her and wash her ears, but if he attempted to put a paw on her back, she would explode into a fit of rage.

Over the years as I have kept more and more males, I have been able to observe their behavior with their mothers when the latter were in estrus. In a majority of the cases, the mothers would not allow their sons' advances. As observed by Marshall Thomas, this is most strongly expressed with our resident males, and much less with their brothers who make occasional visits. It is only the mothers who enforce the incest avoidance; the sons do not seem to possess any such restrictions within themselves.


The aim of this paper has not been to send you all on a "back to nature venture" in your breeding programs. We started interfering with nature over 12,000 years ago, and the journey cannot be backtracked. The aim has been to point out that, in spite of man's interference with the natural selection, many intricate and important mechanisms have survived all along, and we need to respect that if we don't want to produce canine Mayflies -- here today and gone tomorrow.

We will have to apply a certain amount of humility when taking the responsibility of bringing about new life. It will be necessary that we observe and learn as much as possible about the social lives and biology of our dogs, and finally, understand that the two are inseparable in all species -- including ourselves.