The behaviour of the domestic dog (Canis familiaris)
(handout by Peter Kabai for vet students)
Practising veterinarians might be interested to learn about the behaviour of dogs for several reasons:
a) levels of ethological investigations
discuss one specific behaviour (for example urine spraying, aggressive display by adult male dogs) at each level.
b) methods of ethological studies
design an experiment or observation study to test an hypothesis of the function of one specific behaviour
c) "innate" or "learned" behaviour
The terms innate or learned (Nature or Nurture) causing a long lasting debate today is replaced by operational terms. "Innateness" cannot be defined, however, one can study the genetic vs. environmental variance of behaviour (heritability) or the direct mechanism of gene action.
estimation of heritability:
selection and cross studies (see Scott's study on barking in dogs). Genetic variance (at least for the trait studied) is small within a line, and large within hybrid and backcross populations.
Parent-offspring resemblance: heritability equals twice the regression coefficient of offspring on mothers or fathers, because a single parent passes half of its gene to an offpring. Alternatively, heritability can be estimated by analysing both parents, here heritability equals regression coefficient of offspring on midparent values.
gene action: mapping, sequencing DNA, identifying gene product and its function. So far, the major genes identified are involved in diseases and abnormal behaviour. However, the "dog genome" project will provide enough genetic markers to map relevant genes affecting behavioural differences among breeds. Identifying genes and their products will give a clue to the function of those genes.
No idea what genetic markers are? Markers are DNA sequences at known sites within the chromosome. Genes closer to this site are inherited together with the marker with higher probability, because chance of recombination between genes in close proximity is small.
Click at the image to see map of markers on Canince Chromosome 1.
Number of sequenced genes in dog is increasing rapidly. At present (Jan. 2002)
there are 5964 entries in the data base at NCBI.
(Amazing: in only five months, the number of canine DNA sequences have doubled!!! - 11,706 at May 2002)
Please visit NCBI at http://www.ncbi.nlm.nih.gov/htbin-post/Taxonomy/wgetorg?id=9615 and see the present figure (should grow by each week) at the bottom of page (Nucleotid).
visit the dog genome project home page on the Web at:
Cloning a dog: http://news.bbc.co.uk/hi/english/sci/tech/newsid_157000/157711.stm
read the news about dog genome research at my site: ..\..\news\2000\ns-gen-00-05-dog_genome.html
Gene defect in Siberian huskies & Samoyeds offers dog 'model' for studying inherited human blindness
if interested: read paper on genetic study of purebred dog families (rather
NEW - 16 September 2002
Cow and dog genomes next up
National Human Genome Research Institute announces new priorities.
d) normal vs. abnormal behaviour
normality: no clear-cut definition
an example: is "wondering away" of rabies infected foxes normal, abnormal or pathological?
Parasites often modify the behaviour of the infected individual to enhance their own reproductive success: wondering away of the host is beneficial for the parasite, because infected foxes leave their home range and spread the disease to other animals.
This behaviour might be considered abnormal in the statistical sense (rare event), normal in ethological sense (a predictable outcome of inter species arm-race), and pathological in the eyes of the veterinarian (because it is a symptom of a disease, or because it does not lead to recovery).
Sounds simple? Here are some complications for you: wondering away reduces the chance of infecting relatives, and increases the chance of killing non-related, competing families. If true, wondering away might be even beneficial for the family compared with staying within the home range. (See paper by Rozsa at PubMed)
discuss whether a specific behaviour (separation anxiety in dogs) is normal, abnormal or pathological. After you have come up with some idea, please read discussion on normality at http://www.geocities.com/Heartland/Plains/2913/a-english/pathology.html (or at this server)
Origin provides important information about behaviour for vets, because normality in the ethological sense can seldom be evaluated in the present artificial environment of domesticated species.
New studies, such as on mtDNA by Vila et al, Science 276(13)1997 (see abstract at PubMed, or full paper at Science) or Wayne et al, Bioessays 1999 (see abstract at Pubmed) indicate that:
The debate is not over, because only a single gene sequence has been studied so far (1999), therefore timing of separation has a high standard error. The studied mtDNA reflects almost exclusively matrilinear descent, therefore earlier crosses between male coyote or jackal with dog females cannot be excluded.
Figure: Neighbor-joining tree of wolf and dog haplotypes based on 261 bp of
control region sequence
(1) In a recent paper Savolainen et al. investigated mitochondrial DNA of several dog breeds and found the largest genetic variation in East Asia. This suggests, that dogs were domesticated in Asia.
Read news item at BBC: http://news.bbc.co.uk/1/hi/sci/tech/2498669.stm
Sorry: Because I do not have access to Science magazin, I cannot review the possible causes of discrepencies between the two studies.
Genetic Evidence for an East Asian Origin of Domestic Dogs
Savolainen, Zhang, Luo, Lundeberg, Leitner
The origin of the domestic dog from wolves has been established, but the number of founding events, as well as where and when these occurred, is not known. To address these questions, we examined the mitochondrial DNA (mtDNA) sequence variation among 654 domestic dogs representing all major dog populations worldwide. Although our data indicate several maternal origins from wolf, >95% of all sequences belonged to three phylogenetic groups universally represented at similar frequencies, suggesting a common origin from a single gene pool for all dog populations. A larger genetic variation in East Asia than in other regions and the pattern of phylogeographic variation suggest an East Asian origin for the domestic dog, ~15,000 years ago.
Science: Volume 298, Number 5598, Issue of 22 Nov 2002, pp. 1610-1613.
(2) Vilá et al. in a recent paper reported that most New World dog breeds originate in Europe and were brought to the American continant by European colonists
Ancient DNA Evidence for Old World Origin of New World Dogs
Leonard, Wayne, Wheeler, Valadez, Guillén, Vilá
ABSTRACT: Mitochondrial DNA sequences isolated from ancient dog remains from Latin America and Alaska showed that native American dogs originated from multiple Old World lineages of dogs that accompanied late Pleistocene humans across the Bering Strait. One clade of dog sequences was unique to the New World, which is consistent with a period of geographic isolation. This unique clade was absent from a large sample of modern dogs, which implies that European colonists systematically discouraged the breeding of native American dogs.
Science, Volume 298, Number 5598, Issue of 22 Nov 2002, pp. 1613-1616.
Behavioural ecology: Although Carnivora species are predominantly solitary, group formation is relatively common in Canidae, with a mated pair being the social unit. Under certain circumstances the dominant pair may share their territory with one or more subordinates, normally their offspring, sometimes with siblings, and rarely with unrelated individuals. Mating between genetically related individuals must be rare (Smith et al. 1997. Is Incest Common In Gray Wolf Packs? BES 8(4), free at http://www.npwrc.usgs.gov/resource/2000/wfincst/wfincst.htm) (if you have any problem reading the paper, you can download it from this server: wolfe_incest.zip)
Group formation might be advantageous because of communal hunting. A pack of wolves is more efficient to exhaust or round up larger prey than solitary individuals.
Additional benefit of living in groups might be a larger defensible territory.
The range covered by a single pack may be 100 to 600 square kilometres, larger than could be protected by physical presence. Ownership is announced by howling. When an intruder howls from any spot within a pack's territory, the pack members usually howl a warning in return. (In dogs, howling can readily be elicited by high pitched siren sounds.)
This long-range communication is reinforced with more localised, but long-lasting scent marks. Scent marks convey information on the precise boundaries of the territory and the length of time since the pack passed by. Male dogs clearly use urine as marking.
Costs of living in groups can be reduction of recourses (food, mates) per individual
which results in competition. Benefits and costs vary with season and habitat,
stability and size of groups varies accordingly in most Canidae.
Individual trade-offs should be evaluated (not in terms of the "benefit of the species", selection acts predominantly on genes, individuals, possibly on groups, but not on the species).
Benefit of living in group for dominants is evident in higher reproductive success compared with solitary individuals.
Benefit to subordinates is less clear, because subordinate reproduction may be suppressed via social factors, direct interruption of mating or infanticide in wolves. However, most subordinates within wolfe pack are close relatives.
Links: general description of wolfes, behaviour also at http://animaldiversity.ummz.umich.edu/accounts/canis/c._lupus_lycaon
Behavioural signals (see also www)
Living in groups enhances competition but also requires co-operation. In wolves the balance between competition and co-operation is maintained by a relatively strict and stable hierarchy. Wolves recognise each other individually. Fight for status in males starts at a very early age. Fights are more frequent between individuals of similar status.
Agonistic postures are ritualised: readiness to attack or escape is signalled by the ears, lips, and fur, the form of ambiguity (typical aggressive posture) is a mixture of the two extreme signals.
The aggressive dog bares its teeth. Tendency to attack and escape are both present in the display. A dominant male has raised ears, curled lips, a well-defined stop, staring eyes and will make its body appear large and stiff. Submissive males flatten their ears, draw back lips, flatten forehead and narrow the eyes. They might crouch and make their body appear as small as possible and may creep along the ground. How obvious these signals are and when they are shown together depends on circumstances, rank order and so on.
High status is indicated by behavioural signals: elevated position of tail, head, ears and fur. Subordinate status is expressed by infantile or female like behaviour.
Greetings (in African wild dog): pushing the muzzle into the corners of each other's mouth. Licking the muzzle of the other individual (wolves) is performed more often by subordinates (pups beg for food this way).
In a stable hierarchy dominant individuals can control the behaviour of subordinates without direct attacks.
Pic from Dr P' site: http://www.uwsp.edu/psych/dog/dog.htm
Sight: Dogs have two cone pigments, one with peak sensitivity of about 555 nm and a second cone pigment with peak at 430-435 nm. Dogs are therefore not "colour blind", however, they have dichromatic colour vision with less capacity to discriminate among colours than man. Dogs' vision is dominated by rod pigments (with a peak at about 508 nm.), their sight in dim light, ability to differentiate shades of grey, and ability to detect motion surpasses the human visual system.
Hearing: ranges from 20-50 thousand cycles per second. Intensive high pitched tones (not heard by man) can cause severe pain for the dog.
Olfaction: extremely efficient. At rest, nose ventilation is synchronous with lung ventilation. However, while searching for scent, dogs can increase respiratory cycle and duration of constant inhalation. When sniffing, dog is able "to divert exhaled air away from a target scent. When a dog exhales, it moves its nose so that the air is deflected through slits on the side. As a result, the exhaled air flows backwards, away from the smell. This prevents the scent being confused with exhaled air, and sets up a current that pulls new air across the target, launching odour molecules into the air. When dogs inhale they shift their noses into an entirely different shape to draw in a large volume of air" (quote from NewScientist, now can be read here)
Odorants bind to specific receptors in the nasal epithelium. Such olfactory receptors are G protein-coupled, seven-transmembrane-domain proteins. In Canidae, so far, four receptor gene subfamilies have been characterised and sequenced, each having as few as 2 and at least as many as 20 members. Analysis of the four olfactory receptor gene subfamilies in 26 breeds of dog provided evidence that the number of genes per subfamily was stable in spite of differential selection on the basis of olfactory acuity in scent hounds, sight hounds, and toy breeds. (see paper free at PNAS)
Difference among breeds in their efficiency in odour work might be traced back to characteristics not related to olfaction. The Australian Customs Service started a genetic selection program to enhance the dogs ability to detect illegal drugs in luggage at airports. Originally, only 0,1 per cent of ordinary dogs worked properly at such a task Despite the fact, that there is not much genetic variance in smell capabilities among dogs, selection was so successful, that more than 50 per cent of the selected dogs make the grade. Careful study of the selection process revealed, that the genetic program enhanced not smell, but attentional processing needed for work in such a noisy, busy environment, as an airport. See anatomy pic of attention system at this site (120 kB). (Source: New Scientist)
Might be of some interest:
Cognitive capabilities? New Scientist devoted an issue to studies of Csányi's group. Check this out! Dogs can interpret human gestures (see abstract)
NEW (2002-11-22): recent results on dogs, even
puppies, interpreting human gestures corroborates that dogs were genetically
selected to understand human communication.
News item at BBC: http://news.bbc.co.uk/1/hi/sci/tech/2498669.stm
The Domestication of Social Cognition in Dogs
Hare, Brown, Williamson, Tomasello
Dogs are more skillful than great apes at a number of tasks in which they must read human communicative signals indicating the location of hidden food. In this study, we found that wolves who were raised by humans do not show these same skills, whereas domestic dog puppies only a few weeks old, even those that have had little human contact, do show these skills. These findings suggest that during the process of domestication, dogs have been selected for a set of social-cognitive abilities that enable them to communicate with humans in unique ways.
Science: Volume 298, Number 5598, Issue of 22 Nov 2002, pp. 1634-1636.
Coevoluton between man and dog? (here)
Pups are born blind and deaf. The different forms of social interactions appear for the first time when the puppies are between 14 and 21 days of age. Social investigation appears first and is followed by play and agonistic interactions. Barking has been observed as early as 18 days. By 4 weeks old puppies stand and move like adults. Weaning is at 6 weeks.
From week 5, individual differences between the puppies in the tendency to initiate social play and agonistic interactions emerges. Scott and co-workers studied heritability of various behavioural traits in crosses of traditional breeds and found high genetic variation in frequency of barking, emotionality etc.
From 4 weeks old to about 12 the pup establishes social relationships with other dogs and people. The time around week 4-5, possibly up to 12 week old, is a sensitive period for socialisation. Within this time frame the pup learns about its social companions in a rapid, long lasting, imprinting like way. For example, pups up to 5 weeks old readily approach strangers, but after this age, unfamiliar individuals are avoided, avoidance reaching a peak at about 8 weeks (interestingly, the corresponding phase is 8 months in humans). Types of attachment of dogs to human is very similar to attachment between human mother and child (see abstract)
With regards to rearing dogs, it is important to expose the pup to dogs and humans as well during the sensitive period.
Years ago it was common to have dogs with problematic behaviour euthanised. As dogs are becoming companions and family members, owners often seek professional help when troubled by their dog's behaviour.
As a response to such demands, a new field, behaviour therapy of companion animals is emerging. Behaviour therapy is usually done by qualified specialists. Undergraduate and postgraduate courses as part or continuation of applied animal behaviour courses are now available in a number of universities. (see homepage of Anthrozoology Institute
Behaviour therapy of dogs integrate several fields, first of all ethology, human psychology and pharmacology.
Understanding dog behaviour in terms of its evolution and function as discussed in the lecture.
For example, socialising pups to avoid problematic aggressive behaviour later can be based on knowledge of natural hierarchy in wolf packs. Confident omega dogs rarely cause trouble. So, the dog (1) should be kept at the lowest level of dominance in the family, and never let to take over the lead. (2) This should not be done by brute physical force, not only because of welfare concerns, but for practical reasons: the dog should keep its confidence and intimate, trusty relationship with the owner. The most important time to establish such dominant - trusty relation is at the age of 4-12 weeks, during socialisation. Building up a lasting dominant status over the dog is best achieved by canine communication toward the dog. For example, instead of beating the dog it is better to lift and shake the pup lightly. Always reassure the dog by petting and words afterwards.
Psychologists often use dogs as "model animals" to understand biological basis of human nature and abnormal behaviour. For example, Draper (PubMed) studied behavioural traits of 56 breeds of dog and found similarities with human personality models in
If interested: read review by Barsoum et al (Prog Neuropsychopharmacol Biol Psychiatry 2000, ;24(5):811-23) Canine models for human genetic neurodegenerative diseases. in PubMed.
Csanyi and his group at the Ethology Department, ELTE studied attachment in dogs. They performed standard psychological tests on dogs and were able to interpret the dogs' traits by human psychological terms. They found that the dog's relationship to humans is analogous to child-parent and chimpanzee-human attachment behaviour because the observed behavioural phenomena and the classification are similar to those described in mother-infant interactions. (See abstract at PubMed)
New drugs are often developed and tested in animal models. Some researchers
note, that laboratory species normally used in assessing the effects fo drugs
on human psychiatric disorders are not relevant for such questions. Mice and
rats are rodents with high antipredatory responses. Dogs might be more similar
to humans in their behaviour, and behavioural disorders in dogs are analogous,
possibly homologous to those in humans For a discussion see PubMed entry.
For example, most drugs used in the treatment of obsessive-compulsive disorder (OCD) have been originally developed to diminish symptoms of depression in the rodent model. However, OCD and depression can be clearly distinguished in dogs, therefore specific drugs acting on OCD are being now developed in the "canine model". Such studies have just started, please, read these two abstract on this: 1 2.
Animal rights activists often condemn such model studies. Without taking sides in this debate, it should be noted, that such studies would hopefully provide drugs not only to treat humans but dogs also. Recently more drugs affecting behaviour is used in canine behaviour therapy.
Behaviour therapy for dogs
There are plenty of websites now dealing with many aspects of dog behaviour therapy. One of the best, with many link is Dr. P's (Prof. Plomsky) dog training home page of the University of Wisconsin, at http://www.uwsp.edu/acad/psych/dog/lib-prob.htm
Another professional site is the homepage of the Assoc. of Pet Behav. Counsellors: http://www.apbc.org.uk, with very useful articles on behavioural problems at http://www.apbc.org.uk/articles.htm
An excellent source for dog behaviour therapy is at the APPLIED ETHOLOGY HOME PAGE http://www.usask.ca/wcvm/herdmed/applied-ethology/
The International Society for Anthrozoology http://www.soton.ac.uk/~azi/isaz1.htm provides Diploma/MSc courses in Companion Animal Behaviour Counselling.
If you read the advise of professionals you might get the impression, that there are different "schools" of therapy. My impression is that some authors emphasise the ethological aspect, others do classical conditioning while some experts would rely more on drugs, neutering etc. The best results are probably achieved by a clever combination of these. However, all experts agree on the following
Building good habits is most important. The owner should know precisely how the dog would fit into the lifestyle of the family, and be consequent about the most important aspects of the dog's behaviour. If the pup is sometimes allowed to eat from the owner's plate, accept bits of a sandwich, fight for food and win, the owner should prepare that his dog will beg for food all the time, and might even take food aggressively from the hands of strangers. The same is true for other aspects of behaviour.
Use of positive reinforcement is important. A gentle tone, petting the shoulders is reinforcement, such as bits of food. Reinforcement works better, when it is not given all the time. When a desired behaviour is fixed, it is not necessary and should not be reworded by food any more. The dog should and would work for the pack leader without immediate benefits.
Make sure you understand the complaint of the owner. The behaviour owners may complain about might be
If visitng the dog in its environment is not possible ask the owner to collect data. If too much barking is the problem, ask the owner to write down how often, for how long and in what situation would the dog bark.
Some common problems treated by behaviour therapy
According to Ed Frawley (page on aggression)
Overt agonistic behaviour is a real problem for the owner as well as for the practising veterinarian. Mild aggression may be treated with a combination of prevention of injury, increased structure in the home, and safe control of the dog. Unpredictable aggression is less likely to respond to treatment.
While aggression is difficult to cure, it is easier to prevent.
Types of aggression:
Over aggressiveness in dogs has a number of different causes that all can be traced back to 2 different areas - either poor breeding or poor socializing.
If all dogs were well socialized and had gone through basic obedience lessons (either at home or in classes) there would be a lot less problems with dominant and over aggressive dogs. A little bit of education on the handlers part also goes a long way towards producing an animal that is not a danger to society.
One last important point is this " handler aggression towards the dog is not going to eliminate aggression in dogs." This never works. In most cases these dogs have found out that the solution to their problem is aggression. If the handler decide s he is going to "kick some but" with this dog, the dog may decide that the handler is the problem and he has learned to solve his problems with aggression.
There are useful pages on behaviour therapy on the Web. Please, pick one problem and read the link.
Get back to http://www.behav.org
Interesting dog links
EthoDog: homepage for dog ethology, in Spanish only: http://www.ethodog.com/
Drog training book, free: http://home.adelphia.net/~nuxodom/download.htm