Why do adult dogs 'play'?

Among the Carnivora, play behaviour is usually made up of motor patterns characteristic of predatory, agonistic and courtship behaviour. Domestic dogs are unusual in that play is routinely performed by adults, both socially, with conspecifics and with humans, and also asocially, with objects. This enhanced playfulness is commonly thought to be a side effect of paedomorphosis, the perpetuation of juvenile traits into adulthood, but here we suggest that the functions of the different types of play are sufficiently distinct that they are unlikely to have arisen through a single evolutionary mechanism. Solitary play with objects appears to be derived from predatory behaviour: preferred toys are those that can be dismembered, and a complex habituation-like feedback system inhibits play with objects that are resistant to alteration. Intraspecific social play is structurally different from interspecific play and may therefore be motivationally distinct and serve different goals; for example, dogs often compete over objects when playing with other dogs, but are usually more cooperative when the play partner is human. The majority of dogs do not seem to regard competitive games played with a human partner as "dominance" contests: rather, winning possession of objects during games appears to be simply rewarding. Play may be an important factor in sociality, since dogs are capable of extracting social information not only from games in which they participate, but also from games that they observe between third parties. We suggest that the domestic dog's characteristic playfulness in social contexts is an adaptive trait, selected during domestication to facilitate both training for specific purposes, and the formation of emotionally-based bonds between dog and owner. Play frequency and form may therefore be an indicator of the quality of dog-owner relationships.

Repetitive behaviour in kennelled domestic dog: stereotypical or not?

Repetitive behaviour is common in kennelled dogs, yet its motivational basis remains relatively unexplored. We examine the repetitive behaviour of 30 kennelled working dogs in ten contexts both coinciding with, and in the absence of, commonly occurring arousing stimuli, such as care staff, other dogs and food preparation. A large proportion (93%) of subjects performed some repetitive behaviour, most commonly bouncing, but only 17% in the absence of the arousing stimuli. Subjects could be divided into four groups according to the stimuli eliciting, and the duration, of their repetitive behaviour, and these groups were compared on the basis of their cortisol response to an acute psychogenic stressor--a veterinary examination. Urinary cortisol/creatinine response curves differed significantly between the groups. In particular, those dogs which performed repetitive behaviour at times of minimal stimulation, showed a distinctly different pattern of response, with cortisol levels decreasing, as compared to increasing, after the veterinary examination. We conclude that dogs showing repetitive behaviours at times of high arousal are motivationally distinct from those "stereotyping" in the absence of stimulation. We suggest that those dogs showing spontaneous repetitive behaviours may have past experiences and/or temperaments that affect both their reactions to a veterinary examination and to long-term kennelling. For example, some dogs may find isolation from humans particularly aversive, hence affecting their reactions both to being left in a kennel and to being taken to the veterinary surgeon. Alternatively, such dogs may have atypical responsiveness of their hypothalamic-pituitary-adrenal (HPA) axis, possibly brought about through chronic stress. High levels of repetitive behaviours in response to inaccessible husbandry events may be explained if such behaviour has inadvertently been reinforced by attention from staff, and therefore may not always be indicative of aversion to kennelling or compromised welfare.

The effect of familiarity on behavior of kenneled dogs during interactions with conspecifics.

Kenneled environments often prevent direct physical contact between dogs, potentially causing stress, and so it has been recommended that such contact should be provided. This study examined the effect of familiarity on the behavior of dogs during off-lead interaction. Kenneled dogs (3 breeds) were given 15-min off-lead interactions with a familiar dog and an unfamiliar dog; the behavior of the focal dog and the distance between the dogs were recorded. More time in contact and interaction behaviors were recorded at 0 to 3 min with unfamiliar dogs than with familiar dogs. At 9 to 12 min, familiar pairs spent more time within 5 body lengths and more time being followed than unfamiliar pairs, who spent more time at more than 5 body lengths apart. This suggests that the initial interaction is more important when dogs are unfamiliar, but once this "greeting" has occurred, unfamiliar pairs are more likely to investigate their surroundings independently rather than together. Breed differences were observed only at 0 to 3 min. The study suggests that familiarity should be taken into account when assessing the effectiveness of conspecific contact as a potential enrichment for kennel-housed dogs.

Habituation and dishabituation during object play in kennel-housed dogs.

Domestic dogs are reported to show intense but transient neophilia towards novel objects. Here, we examine habituation and dishabituation to manipulable objects by kennel-housed dogs. Labrador retrievers (N = 16) were repeatedly presented with one toy for successive 30-s periods until interaction ceased. At this point (habituation), a different toy was presented that contrasted with the first in both colour and odour (since the dog's saliva would have accumulated on the first), colour alone, or odour alone. No effect of the type of contrast was detected in the number of presentations to habituation, the difference in duration of interaction between the first presentation of the first toy and the presentation of the second toy (recovery), or the duration of interaction with the second toy (dishabituation). Varying the time interval between successive presentations of the first toy up to habituation between 10 s and 10 min had no effect on the number of presentations to habituation, nor did it alter the extent of dishabituation. Varying the delay from habituation to presentation of the second toy, between 10 s and 15 min, affected neither the recovery nor the dishabituation. Overall, the study indicates that loss of interest in the object during object-orientated play in this species is due to habituation to the overall stimulus properties of the toy rather than to any single sensory modality and is also atypical in its insensitivity to the interval between presentations.

Dog behaviour on walks and the effect of use of the leash.

This paper describes how often pet dogs interact with other dogs, people and the environment, whilst being walked. Such interactions may involve aggression or the transmission of infectious disease. We also assessed the effect of the use of a leash as a modifier of these outcomes. In study one, the behaviour of pet dogs being walked in popular public walking areas was observed (286 observations). Interactions with people were much rarer than interactions with dogs. Multivariable modelling suggested that percentage duration spent sniffing the ground was associated with the UK Kennel Club Breed Type, and whether the dog was observed urinating. Gundogs were observed to sniff more than other breed types. In study two, dogs (n = 10) were filmed twice walking along a pre-defined route, alternately once on leash and once off leash, in order to assess the effects of leash use on interactions between the subject dog and any other dog or person encountered. Multilevel modelling suggested that if either dog was on the leash, then the likelihood of an interaction with a dog occurring was reduced. There was no evidence for statistical interactions between these variables, therefore the effect of the leash on one dog did not seem to be influenced by whether the other dog was on or off leash. We conclude that in circumstances where interactions need to be prevented, such as to reduce spread of infectious diseases during an outbreak, both dogs should be leashed.

The effect of feeding enrichment upon reported working ability and behavior of kenneled working dogs.

It is widely recommended that kenneled dogs are provided with environmental enrichment such as toys or feeding devices. However, the adoption of enrichment for military working dogs is impeded by a widespread belief that it reduces their motivation to work. Handlers of 22 working German Shepherd dogs were asked to rate their dogs on 11 attributes pertaining to working ability, related behavioral traits, and health. Eight of the dogs were then provided with daily feeding enrichment for 4 months, while the remainder were given equivalent human attention. The same 11 traits were scored again following the enrichment period: 10 changed little over the period while handlers' reports of their dogs' Ability to learn from being rewarded increased significantly. Changes for all attributes were virtually identical in enriched and control dogs. We conclude that if correctly managed, feeding enrichment can be introduced to kenneled working dogs without any reported detrimental effects upon working ability, health, or behavior.

Behavioural and glucocorticoid responses of dogs (Canis familiaris) to kennelling: Investigating mitigation of stress by prior habituation.

We have explored the validity of urinary cortisol/creatinine ratios (C/C) and behavioural measures as indicators of acute psychological stress in the domestic dog, by monitoring 1 year old male Labrador Retrievers (N=31) prior to and following their introduction to novel kennels in a training establishment. Baseline early morning urine samples were taken in the dogs' original homes and then urine samples and remote recordings of behaviour were taken for ten consecutive days after transfer to the kennels. The impact of this potential stressor was manipulated by previously habituating half of the subjects to confinement in a kennel. We hypothesised that stress levels would increase upon introduction to the training establishment, but that the response would be mitigated by kennel habituation. C/C increased in all dogs when they entered the training establishment, this increase was significantly higher in the non-habituated group, and in this group C/C remained above baseline even 12 weeks after transfer. Despite the homogeneity of the subjects, the behaviour measured showed very little correlation to the C/C ratios, and the changes in behaviour that were observed, such as decreases in whining and time spent at the front of the kennel, could equally be attributed to dogs learning the most effective strategies for gaining human attention in the kennels as to attenuation of stress. We conclude that urinary C/C is a valuable indicator of acute stress and hence welfare status in dogs, but that behavioural measures need to be interpreted with caution due to individuality in coping strategies.

Factors associated with dog ownership and contact with dogs in a UK community.

BACKGROUND: Dogs are popular pets in many countries. Identifying differences between those who own dogs or have contact with dogs, and those who do not, is useful to those interested in the human-animal bond, human health and for provision of veterinary services. This census-based, epidemiological study aimed to investigate factors associated with dog ownership and contact with dogs, in a semi-rural community of 1278 households in Cheshire, UK. RESULTS: Twenty-four percent of households were identified as dog-owning and 52% owned a pet of some type. Multivariable logistic regression suggested that households were more likely to own a dog if they had more occupants (five or more); if they had an adult female household member; or if they owned a horse. The age structure of the households was also associated with dog ownership, with households containing older children (between six and 19 years of age) and young adults (between 20 and 29 years of age), more likely to own dogs. We also found that dog owning households were more likely to be multi-dog households than single-dog if they also owned a cat or a bird, or if the household contained a person of 20-29 years old. Dog owners reported increased contact with dogs, other than their own, compared to those that did not own dogs and this contact appeared to be mainly through walking. CONCLUSION: Some household types are more likely to own a dog than others. This study supports the suggestion that dogs are more common in families who have older children (6-19 years), as has been generally observed in other countries. Dog owners are also more likely to have contact with dogs other than their own, compared with those not owning a dog.

Behavioural and physiological responses of dogs entering re-homing kennels.

Behaviour and urinary cortisol/creatinine ratios (C/C) were monitored in twenty-six dogs, on days 1, 2, 3, 5, 7 and 10 following their admission to a rehoming kennel. Half had been relinquished from homes, and half were either strays or returns to the shelter. Drinking and grooming increased with time, while panting and paw-lifting decreased, but only drinking was linked with C/C; dogs observed drinking on the first day had significantly lower C/C than dogs not observed drinking. Mean molar C/C (40 x 10(-6)+/-16 x 10(-6)) tended to decrease with time in the strays and returns, and to increase in dogs relinquished from homes, although C/C on the first day was highly variable and not distinguishable between these two groups. This implies that these populations differed in their long-term, but possibly not their short-term, responses to kennelling. Dogs with rising C/C were more active on average than those with falling C/C, but the opposite trend was detected when making comparisons within-dog. The relationship between C/C and exercise is therefore complex and warrants further investigation before C/C can be considered as a reliable indicator of welfare in this species.

The evolutionary basis for the feeding behavior of domestic dogs (Canis familiaris) and cats (Felis catus).

The dentition, sense of taste and meal patterning of domestic dogs and cats can be interpreted in terms of their descent from members of the order Carnivora. The dog is typical of its genus, Canis, in its relatively unspecialized dentition, and a taste system that is rather insensitive to salt. The preference of many dogs for large infrequent meals reflects the competitive feeding behavior of its pack-hunting ancestor, the wolf Canis lupus. However, its long history of domestication, possibly 100,000 years, has resulted in great intraspecific diversity of conformation and behavior, including feeding. Morphologically and physiologically domestic cats are highly specialized carnivores, as indicated by their dentition, nutritional requirements, and sense of taste, which is insensitive to both salt and sugars. Their preference for several small meals each day reflects a daily pattern of multiple kills of small prey items in their ancestor, the solitary territorial predator Felis silvestris. Although in the wild much of their food selection behavior must focus on what to hunt, rather than what to eat, cats do modify their food preferences based on experience. For example, the "monotony effect" reduces the perceived palatability of foods that have recently formed a large proportion of the diet, in favor of foods with contrasting sensory characteristics, thereby tending to compensate for any incipient nutritional deficiencies. Food preferences in kittens during weaning are strongly influenced by those of their mother, but can change considerably during at least the first year of life.

Attributes of specialist search dogs--a questionnaire survey of UK dog handlers and trainers.

The ideal and actual characteristics of specialist search dogs have been examined in questionnaire surveys of 244 dog handlers and trainers from the six main UK dog-using Government agencies. The ten most important characteristics were (ideal level in brackets): acuity of sense of smell (very high), incentive to find an object which is out of sight (very high), health (very high), tendency to hunt by smell alone (very high), stamina (very high), ability to learn from being rewarded (very high), tendency to be distracted when searching (very low); agility (high), consistency of behaviour from day to day (high), motivation to chase an object (high). Significant differences between actual and ideal levels were found for 22 of the 30 characteristics, predominantly in undesirable attributes, suggesting that there is scope for significant improvement in operational effectiveness.

Links between play and dominance and attachment dimensions of dog-human relationships.

It is often claimed that certain behavioral problems in domestic dogs can be triggered by the games played by dog and caregiver (owner). In this study, we examine possible links between the types of games played and dimensions of the dog-owner relationship that are generally considered to affect such problems. Fifty dog-owner partnerships were filmed during 3-min play sessions in which the owner was allowed to choose the games played. All partnerships then undertook a 1-hr test designed to measure elements of behavior commonly ascribed to "dominance" and "attachment." Principal components analysis of the data produced 2 dominance-related factors (Amenability and Confident Interactivity) and 4 factors describing aspects of attachment (Nonspecific Attention Seeking, Preference for Owner, Preference for Unfamiliar Person, and Separation-Related Behavior). Amenability, in particular, varied significantly between breeds. In the study, we then compared types of games played to each of these factors. Dogs playing rough-and-tumble scored higher for Amenability and lower on Separation-Related Behavior than did dogs playing other types of games. Dogs playing tug-of-war and fetch scored high on Confident Interactivity. Winning or losing these games had no consistent effect on their test scores. If the dog started the majority of the games, the dog was significantly less amenable and more likely to exhibit aggression. The results suggest that how dogs play reflects general attributes of their temperament and relationship with their owner. This study provides no evidence that games play a major deterministic role on dominance dimensions of dog-human relationships, but the results suggest that playing games involving considerable body contact may affect attachment dimensions.

Ontogeny of individuality in the domestic cat in the home environment.

The behaviour of house cats Felis silvestris catus from nine litters was recorded at 4 months, 1 year and 2 years of age, in their home environment immediately after meals fed by their owners. We extracted by principal components analysis four elements of 'behavioural style' that were consistent from one age to another: based upon behaviour patterns that were most heavily loaded on each component, these were labelled as Staying Indoors, Rubbing, Investigative and Boldness elements. The Staying Indoors and Rubbing elements are similar to two aspects of behavioural style identified in a previous study of adult cats; the Boldness element, possibly coupled with the Investigative element, may be similar to the shy/bold continuum identified in controlled studies of cats and other species. Four-month-old male cats were the most likely to Stay Indoors; the Rubbing element increased with age in the majority of individuals, both male and female. Littermates tended to be similar to one another in Rubbing (at 4 months) and Boldness (up to 1 year). A positive effect of handling received during the first 8 weeks of life was detected for Boldness at 4 months of age. Copyright 2001 The Association for the Study of Animal Behaviour.