Captive Pack Research Articles

Inter-individual Distance in Different Captive Packs of Iberian Wolf (Canis lupus signatus): Management Applications

ABSTRACT There is a tendency for the wolves of a pack to stay together assuming that there is a social bond between the pack members. A rough estimate of the strength of this bond can be obtained by measuring the distances between pack members. The aim of this study was to determine the inter-individual distance by calculating the Euclidian distance to determine the Iberian wolf cohesion in different pack compositions. The study subjects were seven captive Iberian wolves (Canis lupus signatus) housed at the Barcelona Zoo. Multifocal sampling methods were used for data collection, and instantaneous scans were made at 15-min during different sessions. Proximity relationships among these wolves in different pack composition were visualized using two-dimensional scaling analysis. The pair leader without offspring and the breeding pair with their offspring were significantly closer than the rest of the dyads which combinations were equidistant. During the pregnancy period, the breeding pair was significantly further than during the juvenile period. More studies in field and captivity by using Euclidian distance are necessary to improve social husbandry techniques, animal welfare and conservation programs.

Feeding Enrichment in a Captive Pack of European Wolves (Canis Lupus Lupus): Assessing the Effects on Welfare and on a Zoo's Recreational, Educational and Conservational Role.

Simple SummaryFeeding enrichment is widely used to improve the welfare of zoo animals, but it may also affect zoo visitors’ experience and perception of the animals. The objective of this study was to assess the effects of a naturalistic and a non-naturalistic feeding enrichment program, on both wolf behaviour and visitors’ interest in the exhibit. A questionnaire was administered to visitors with the aim of assessing whether our feeding enrichment programs might affect their perception of captive wolf welfare as well as their attitude towards wolf conservation issues. Our findings suggest that, although wolves seemed to benefit from enrichment, their behavioural responses were highly variable among individuals. Visitors’ interest in the exhibit and perception of captive wolf welfare improved by observing the wolves interacting with food, especially when novel feeding objects were provided. Finally, their attitude towards wolf conservation issues did not change in relation to enrichment, but improved when they observed the wolves performing feeding-related behaviours. These findings may help zoos implement enrichment programs that are effective for enhancing their wolves’ welfare as well as their recreational and educational role.This study investigated the effects of two feeding enrichment programs on the behaviour of a captive pack of European wolves (Canis lupus lupus) and their correlation with both zoo visitors’ interest towards the exhibit and their overall perception of the species. Behavioural data (exploration, stereotypies, social interactions, activity/inactivity rates) were collected on four male wolves during four two-week long phases: initial control, hidden food, novel object, final control. Three observation sessions were performed daily: before, during and after feeding. Number of visitors and their permanence in front of the exhibit were recorded. After watching the wolves, visitors were asked to fill out a brief questionnaire in order to investigate their perception of captive wolf welfare, as well as their attitude towards wolf conservation issues. Despite the high inter-individual variability in their behavioural response, all wolves seemed to benefit from feeding enrichment. With regard to visitors, interest in the exhibit increased when enrichment was provided. Visitors’ perception of the level of welfare of wolves improved if they attended a feeding session, especially during the novel object phase. Visitors’ attitude towards wolf conservation issues also improved during feeding sessions, regardless of enrichment provision.

Dominance relationships in a family pack of captive arctic wolves (Canis lupus arctos): the influence of competition for food, age and sex.

BackgroundDominance is one of the most pervasive concepts in the study of wolf social behaviour but recently its validity has been questioned. For some authors, the bonds between members of wolf families are better described as parent-offspring relationships and the concept of dominance should be used just to evaluate the social dynamics of non-familial captive pack members (e.g., Mech & Cluff, 2010). However, there is a dearth of studies investigating dominance relationships and its correlates in wolf family packs.MethodsHere, we applied a combination of the most commonly used quantitative methods to evaluate the dominance relationships in a captive family pack of 19 Arctic wolves.ResultsWe found a significant linear and completely transitive hierarchy based on the direction of submissive behaviours and found that dominance relationships were not influenced by the competitive contexts (feeding vs. non-feeding context). A significant linear hierarchy also emerges amongst siblings once the breeding pair (the two top-ranking individuals) is removed from analyses. Furthermore, results suggest that wolves may use greeting behaviour as a formal signal of subordination. Whereas older wolves were mostly dominant over younger ones, no clear effect of sex was found. However, frequency of agonistic (submissive, dominant and aggressive) behaviours was higher between female–female and male–male dyads than female–male dyads and sex-separated linear hierarchies showed a stronger linearity than the mixed one. Furthermore, dominance status was conveyed through different behavioural categories during intra-sexual and inter-sexual interactions.DiscussionCurrent results highlight the importance of applying a systematic methodology considering the individuals’ age and sex when evaluating the hierarchical structure of a social group. Moreover, they confirm the validity of the concept of dominance relationships in describing the social bonds within a family pack of captive wolves.

Testing the myth: tolerant dogs and aggressive wolves.

Cooperation is thought to be highly dependent on tolerance. For example, it has been suggested that dog–human cooperation has been enabled by selecting dogs for increased tolerance and reduced aggression during the course of domestication (‘emotional reactivity hypothesis’). However, based on observations of social interactions among members of captive packs, a few dog–wolf comparisons found contradictory results. In this study, we compared intraspecies aggression and tolerance of dogs and wolves raised and kept under identical conditions by investigating their agonistic behaviours and cofeeding during pair-wise food competition tests, a situation that has been directly linked to cooperation. We found that in wolves, dominant and subordinate members of the dyads monopolized the food and showed agonistic behaviours to a similar extent, whereas in dogs these behaviours were privileges of the high-ranking individuals. The fact that subordinate dogs rarely challenged their higher-ranking partners suggests a steeper dominance hierarchy in dogs than in wolves. Finally, wolves as well as dogs showed only rare and weak aggression towards each other. Therefore, we suggest that wolves are sufficiently tolerant to enable wolf–wolf cooperation, which in turn might have been the basis for the evolution of dog–human cooperation (canine cooperation hypothesis).

Seasonal Trends in Intrapack Aggression of Captive Wolves (Canis lupus) and Wolf-Dog Crosses: Implications for Management in Mixed-Subspecies Exhibits

Mixed-species exhibits are becoming increasingly common in the captive management of a wide range of species. Systematic evaluations of enclosures consisting of multiple subspecies, however, are relatively infrequent. The aim of this study was to measure seasonal trends in aggressive behaviors within a captive pack of wolves and wolf-dog crosses in a sanctuary setting. The frequency of intrapack social behaviors occurring within scan-sampling intervals was recorded for wolves and wolf-dog crosses during autumn, winter, and spring (2008–2009). Both subspecies displayed distinct seasonal trends in aggression. Wolf-dog crosses exhibited overall higher levels of aggression than wolves, although these instances were mostly noncontact and no significant differences were observed in the relative frequencies of aggressive behaviors between subspecies during any season. These findings suggest that wolves and wolf-dog crosses may be housed successfully given continuous behavioral monitoring, and these findings represent the first empirical account of wolf-dog cross behavior directly compared to wolves. Future studies should be conducted with similar packs to determine if this dynamic is universal. Such research will aid in the development of management and welfare strategies for captive facilities that provide permanent residences for wolves and wolf-dog crosses.

Reducing Potential Sources of Sampling Bias When Quantifying the Diet of the African Wild Dog Through Scat Analysis

To develop guidelines for the collection of independent field samples of scats for the quantification of wild dog (Lycaon pictus) diet we determined the passage rates of different wild dog prey items from feeding trials on a captive pack held at Marakele National Park, Limpopo Province. The minimum time to first detection was 5.5 hours after feeding (S.E. ± 1.52, n = 5) and prey items remained in the gut for an average of 79.4 hours (S.E. ± 6.00, n = 3). Differential passage rates of prey species were not pronounced. Observed passage rates were used to devise a sampling protocol for scats collected during a field study where scats were separated by a minimum period of 120 hours to ensure independence of samples. Comparison of the percentage occurrence of prey species in field-collected scats with the percentage occurrence from direct observations of kills illustrated the tendency for small prey to be underrepresented in the latter. However, the strong correlation between percentage occurrences in diet as determined by the two methods (r s = 0.85, P < 0.01, 13 d.f.) suggests that both methods can reliably determine the relative importance of prey in the diets of obligate carnivores such as wild dogs. The determination of maximum passage rates and subsequent guidelines for collection of independent faecal samples in the field could be a valuable tool for reducing inherent biases in carnivore diet studies.

An uneasy alliance: unequal distribution of affiliative interactions among members of a captive wolf pack

The social groups of many vertebrates may be characterized as "uneasy alliances" that reflect tensions between benefits of group membership and costs to individual fitness among members, especially nonrelatives. The prebreeding season may be a time when these tensions become most acute and so observable for packs of gray wolves (Canis lupus). We recorded affiliative (play) interactions among two females and five males of known social ranks in a captive pack as the time of breeding approached. Substantial inequalities among pairs of wolves were apparent in frequencies of both the initiation of play and the exhibition of positive responses by recipient wolves. With the subsequent arrival of the breeding season, the pack experienced social disruption that led to the eviction of the original alpha male and a reordering of the ranks of those wolves remaining. Our data suggest that unequal affiliative interactions among pack members can be associated with (and, perhaps, even be predictive of) subsequent social disruption at a time when opportunities for personal reproduction become most available.

Patterns of coalition formation and spatial association in a social carnivore, the African wild dog (Lycaon pictus)

In many social species, relationships within groups seem to be non‐random but related to variables such as rank, kinship or sexual attractiveness. The endangered African wild dog Lycaon pictus is a social carnivore that lives in large, stable packs, and intra‐pack associations might be expected to display similar patterns. We investigated patterns of coalition formation (support during dominance interactions, and partnership interactions) and resting associations between members of a captive pack of 19 wild dogs. The social organization of the captive pack was similar to that of free‐ranging packs in many respects. Polyadic (group) incidents of coalition support were also observed in a free‐ranging pack. Patterns of coalition formation in the captive pack were related to rank. Most aggressive interactions involved high‐ranking individuals (particularly the alpha, beta and third‐ranking males) and coalitionary support tended to reinforce the existing hierarchy. However, there was at least one example of support influencing a successful rank challenge. Support was affected by potential risks and benefits, the latter including dominance through association and revolutionary alliances. An even stronger pattern overlaid associations between pack members: coalitions and resting associations were strongest between members of the same age–sex cohort, and may have enabled the eventual dominance of younger pack members over adults. Among adults, coalitionary associations were sometimes overridden by intersexual relationships. The results from this captive pack suggest that wild dogs are sensitive to differences in competitive ability. This information, in conjunction with strong affiliative bonds between littermates, is used to manoeuvre for position in the social hierarchy. It may also be important during dispersal, in encounters with other dispersing groups of the same sex. Although most features of the social structure of the captive pack were comparable to those of free‐ranging packs, aspects such as the influence of relatedness on coalition formation still need to be explored.

The influence of pack social structure on oral rabies vaccination coverage in captive African wild dogs ( Lycaon pictus)

This paper examines the application of oral immunisation against rabies in African wild dog ( Lycaon pictus), a highly social species that is currently endangered. The influence of pack social structure on consumption of baits was studied in an artificially created captive pack of seven adult wild dogs, which were all habituated to feeding. Observations on spatial relationships and aggressive behaviour revealed a distinct split within the pack into two subgroups: dominants and subordinates. Dominant animals actively defended baits from subordinates, but this behaviour appeared to decrease when the dogs were satiated, and there was no difference in mean bait consumption between the two subgroups when baits were scattered over a wide area. A pack vaccination coverage of 100% was achieved over 2 days, using the scattered method to deliver two chicken head bait/vaccine combinations per dog per day. Pack members ingested between 2 and 8 bait/vaccines over the 2 days. The behavioural responses of captive and free-ranging packs to oral immunisation methods are discussed.

Social Dynamics and the Cortisol Response to Immobilization Stress of the African Wild Dog,Lycaon pictus

The aims of the study were to characterize the cortisol response to immobilization stress in African wild dogs (Lycaon pictus) and to investigate the relationship between stress and sociality in these pack-living canids.Ad lib.observations were made on a captive pack of 19 wild dogs. Individuals were classified as either dominant or subordinate. Cardinal and ordinal dominance indices were also calculated for pack members, as were three other behavioral indices. Active and passive dominance styles were distinguished. Serial blood samples were drawn from animals after chemical immobilization and again after ACTH challenge. The relationship among rank, plasma cortisol concentration, and behavioral style was investigated. When data were combined over the entire study period, there was no obvious relationship between rank and cortisol concentrations or cortisol responsiveness to immobilization stress. Instead, younger animals had higher cortisol concentrations than older ones. Age cohorts were also clearly separated on the basis of behavioral profiles. For males, these distinctions among age classes were especially apparent during the second part of the study period, when subadults occupied dominant positions in the hierarchy. Adult males maintained relatively low cortisol concentrations, despite being involved in and losing a high proportion of dominance interactions. Age-related differences in cortisol profiles of dominant individuals may be explained by differences in the style of dominance employed, with younger males using proportionately more active dominance (threats used to elicit submission). The separation of age classes according to rank, behavioral styles, and cortisol concentrations may reflect improved social skillfulness with age.

Social behaviour of captive bush dogs (Speothos venaticus)

The bush dog, Speothos venaticus, is a rare forest‐dwelling South American canid. Social behaviour of a captive pack of three adult males and three adult females was observed over four years in a large enclosure. The dogs appeared to be compulsively sociable, sleeping in close physical contact, travelling together in single file, and feeding communally with minimal aggression. An alpha pair was dominant, but there was no clear hierarchy within the pack as a whole. There were, however, separate male and female hierarchies. The pack engaged in various communal behaviours, including greeting ceremonies in which individuals mutually submitted to one another. All dogs urine marked frequently, both sexes adopting postures to direct urine upwards and to soak their fur in odour. Only the alpha female bred successfully, and all other group members carried and guarded the young. These observations are discussed in the contexts of canid social behaviour and the breeding in captivity of this endangered species.

Infanticide by female wolves

Video recordings made inside wolf dens chronicle two episodes of infanticide by different α females within a captive pack of timber wolves (Canis lupus). In one instance, infanticidal behaviour was interspersed with maternal behaviour. These cases are discussed in terms of the proximate causes of infanticide. It is also suggested that the killing of pups born to subordinate females by α females may be a common occurrence in both captive and free-ranging wolf packs.

Induction of normal prepubertal behavior in wolves with restricted rearing

A series of studies in which wolves were born and reared in a population field as members of a variety of captive packs had been previously undertaken in our laboratory. Two females were each isolated from conspecifics at 4 weeks of age and individually reared as pets until 6 months of age in a household containing a domestic dog. One of these was included in the socialization procedures to conspecifics used in the present study. Another female (previous study) was taken from the mother on the second day after birth and bottle-raised until 9 weeks, when it was isolated from conspecifics until 10 months of age and then socialized ( B. E. Ginsburg, in Communicative Behavior and Evolution , pp. 59–79, Academic Press, New York, 1976 ). In the present study, six wolf pups were subjected to a variety of regimes of rearing and handling beginning at 4 weeks of age. Two males were isolated from humans and conspecifics from 4 weeks to 6 months of age, with minimal human handling from weeks 4 to 6. One male was socialized to humans beginning at 4 weeks of age, but had no experience with conspecifics from 4 weeks to 6 months of age. Two females were pair-housed from 4 weeks of age to 6 months of age, with minimal human contact from weeks 4 to 6 and intensive socialization with humans thereafter. At 6 months of age, the animals, with the exception of one male isolate who died, were paired in a series of round-robin encounters lasting 1 day each and subsequently group-housed for 5 days. Videotapes of the interactions, obtained without humans present, revealed that after a variable period of adjustment the animals exhibited behaviors normally seen in wolves of this age on the first day of pairing. The group encounters also demonstrated that normal social behavior, including normal group structure, could develop within this time span. The animals, with the exception of the dominant male, reacted with appropriate submissive behavior to an adult female. The results are discussed with reference to the previous canid isolation literature, and it is concluded that normal social behavior in wolves is sufficiently well buffered from environmental effects to permit rapid recovery from aberrant conditions of rearing, under appropriate experimental circumstances.

Scent-marking in lone wolves and newly formed pairs

Scent-marking was studied in wolves ( Canis lupus) along 133 km of tracks in northern Minnesota during winters of 1975 to 1976 and 1976 to 1977 and in two captive packs and four captive pairs for various periods. Lone wolves, which possess neither mates nor territories, rarely marked by raised-leg urination and defaecated and urinated less along roads and trails, where territorial pairs and packs generally marked. Newly formed pairs marked the most, eventually decreasing their rates to those of established packs. Generally, wolves that scent-marked also bred, whereas non-marking wolves usually did not breed. Scent-marking apparently is important to the success of courtship in new pairs and to reproductive synchrony in established pairs, as well as serving a territorial function.

Social Dynamics of Three Captive Wolf Packs

AbstractThis study probes the intrinsic complexities of the social organization and inter-individual relationships in three captive packs of wolves; behavior profiles of members of two of the packs had been determined earlier during infancy. The effects of removal and reintroduction of dominant and second ranking yearling wolves in two of the packs and of dominant and most subordinate wolves in a third pack were observed. A greater cohensiveness or unity in the higher ranks of the pack, based upon the "tension" effect of attraction-affection and aggression-domination is proposed. The social significance of paradoxical ambivalent aggression and the relationships between active and passive submission and play behavior are discussed.