The aggressive behaviour of individual male polecats (Mustela putorius, M. furo and hybrids) towards familiar and unfamiliar opponents

Experiments are described which were designed to investigate the significance of individual differences in aggressiveness between polecats and the relation between the familiarity of the opponent and the pattern and outcome of fighting.
The behaviour of Mustela putorius, M. furo and hybrids between the two species was investigated in an indoor arena of 16 m².
Two kinds of fighting between male polecats were recorded, "companion fighting" between cage mates, in which biting was inhibited and neither of the opponents became intimidated and "uninhibited fighting" between unfamiliar individuals from which a winner and loser generally emerged and a rank order formed.
Individual differences in aggressiveness were assessed by means of a scoring system which statistical analysis showed, generally, to be consistent for any one individual. The rank of an animal, however, was found not to be invariably related to its aggression score.
A number of other factors influencing fighting were investigated, the earlier introduction of one individual into the arena increases its chances of winning a fight; when offered a choice, male polecats fight strangers in preference to cage mates; and the separation of a group of cage mates for as little as 48 hours induces them to behave towards one another like strangers with the result that a rank order is formed. Factors which had no apparent effect on fighting between males were the weight of the individual or the presence of females.
The attributes of familiar and unfamiliar opponents are discussed in the light of these findings.     

Individual piglets' contribution to the development of tail biting

Conflicting hypotheses exist about the contribution of individual pigs to the development of a tail-biting outbreak, but there is limited quantitative information to support or dismiss them. This study aims to quantify the development of tail-biting behaviour at pen and individual piglet level, before and after the first visible tail damage. Video recordings of 14 pens with tail-biting outbreaks and individually marked weaned piglets were used to observe tail-biting incidents (TBIs; piglet biting a penmate's tail). When visible tail damage was first observed in a pen (i.e. day of tail biting outbreak; D0), the video recordings of the previous 6 (till D-6) and the following 6 days (till D6) were analysed every other day for TBIs and the identities of the biter and bitten piglet were recorded. The average TBIs per individual piglet (within each pen) per observation day were analysed to quantify the development of tail-biting behaviour and to identify pronounced biters and/or bitten piglets. The (absence of) coherence for TBIs in a pen was used to test whether biters preferred a specific penmate. There was an exponential increase in the intensity (linear on log scale) of the TBIs from an average of 0.7 bites/h at D-6 to 2.3 bites/h at D6. An additional negative quadratic component suggests that a plateau for tail-biting behaviour was reached by the end of the observation period. Before any visible tail damage was observed (i.e. before D0), 82% of the piglets performed and 96% of them received tail bites. After D0, the figures were 99% and 100%, respectively. One or a few pronounced biters could be identified in almost all pens. These biters already showed more tail biting at D-6 than their penmates. Furthermore, these biters showed a greater increase in tail-biting behaviour during the observation period than the average scores of their penmates. In contrast, there was no apparent increase in the receipt of bites among the piglets that had already been bitten more than their penmates at D-6. Finally, there was no significant coherence between biters and bitten piglets, indicating that biters showed no preference for biting particular penmates, even when some of them had a damaged tail. These results show that, by using observations of TBIs, possible biters or bitten piglets can already be identified 6 days before tail damage is first apparent in a pen.     

Characteristics of American alligator bites on people in Florida

Human–American alligator (Alligator mississippiensis) conflict in Florida, USA, has increased since the early 1970s, along with the recovery of the American alligator population. To better understand factors contributing to the risk of people being bitten by free-ranging alligators in Florida, we evaluated the trend of alligator bites during 1971–2014 and examined characteristics associated with bites on people documented during 1948–2014. We classified 372 bites as either unprovoked or unintentionally provoked and used these in further analyses. Major injuries to victims occurred in 247 bite incidents. The estimated annual number of bites resulting in major injury to the victim increased from 3.5 to 7.0 during 1971–2014. The number of bites per Florida resident did not show a significant trend during 1971–2014. No significant change occurred in the frequency of fatal attacks during 1971–2014. Monthly frequency of bites was positively correlated with both mean maximum and mean minimum air temperatures but was not significantly correlated with testosterone concentration in adult male alligators, suggesting that bites are more likely related to feeding rates associated with seasonal fluctuations in ambient temperature than to aggression by male alligators during the breeding season. A high percentage of bites (41.8%) occurred in unnamed water bodies, which were generally small or man-made. Most (93.7%) victims were Florida residents, and 58.7% resided close to the incident site. Victims were predominantly male (81.4%), and adults were more frequently victims than were adolescents or children. Most victims (93.9%) were in the water or near the shore when bitten. Victims were more likely to sustain major injuries if the bite occurred in deeper water. Male alligators were more frequently (76.9%) responsible for bites. We found only 1 instance in which a bite was associated with defense of eggs or young by an adult female alligator. Evidence of people feeding alligators before the bite was documented in 34.7% of bite incidents. Twenty-two fatalities were attributed to alligator attacks, but we could not discern a pattern in the ages of victims. Alligators responsible for severe or fatal bites were predominantly in good condition with few deformities or injuries. Most alligator bites in Florida appeared to be attempts at feeding, although 36.8% of incidents entailed a single bite followed by immediate release, suggesting that alligators were unsure about their prey or were biting in defense. The risk of alligator bites can be reduced by educating people likely to interact with alligators and by selectively removing problem alligators in human residential areas and water bodies used regularly by people for swimming, wading, and shoreline activities. © 2019 The Wildlife Society.     

艾虎对不同猎物的选择性

在室内条件下,将高原鼢鼠(Myospalaxbaileyi)、高原鼠兔(Ochotonacurzoniae)和根田鼠(Microtusoeconomus)作为艾虎(Mustelaeversmanni)的猎物选择对象,研究艾虎对猎物的选择性及艾虎捕杀猎物的行为时间分配。实验结果表明:艾虎对三种猎物的搜寻时间和搜寻频次基本一致,在搜寻猎物的过程中并非已知洞道系统中所存在的食物信息,是一种机会主义的捕食者;艾虎除了具有典型鼬科动物捕杀猎物的方法外,能够根据猎物的大小、活动性和反捕食能力采用不同的捕杀方法,在捕杀猎物的过程中首先捕杀高原鼢鼠,其致死部位全部为头部,其次捕杀高原鼠兔,其致死部位除了头部外,明显增加了颈部的比例,最后捕杀根田鼠,其致死部位主要是头部和胸部;艾虎在捕杀猎物的过程中,追击根田鼠的时间最多,追击鼢鼠的时间最少,而用于捕杀根田鼠的时间最少,用于捕杀鼢鼠的时间最多,艾虎捕杀高原鼠兔后单位时间内获得的能量值最大,其次为捕杀高原鼢鼠,而捕杀根田鼠后单位时间内活动的能量值最小。因此,在室内条件下艾虎对猎物的选择性主要依赖于其本身处理猎物的行为时间分配和猎物的反捕食行为,使单位时间内获得的能量值最大.     

Visitor-directed aggression among the Gibraltar macaques

Animal parks and exhibits which offer visitors the option of close interaction with the animals displayed have been very successful with some species, including primates. However, there is always an element of risk to the visitor who enters another species' environment and interacts with its members. This risk factor may cause particular concern when the exhibit animal is a nonhuman primate because of the transmission of various zoonoses. The Barbary macaques (Macaca sylvanus) at Queen's Gate, Gibraltar, attract large numbers of tourists who are permitted to feed them. This animal-human contact sometimes results in monkeys biting visitors. Bite frequency data from hospital records for 1980–1989 and direct observations (July 1990–June 1991) form the basis of this study. Biting is a density-dependent phenomenon since monkey-visitor aggression rates increase with visitor numbers. Time of day affects bite rates, more people being bitten in the afternoon—the main visitation time. Likewise, more bites are recorded during summer months when visitor numbers are higher. A tendency towards acclimatization of the monkeys to the very large number of visitors appears after 1985. Rank correlation coefficients between visitor numbers and bites per month fall from 1985 to 1989, reflecting a drop in visitor density response. Analysis of visitor profiles indicates a negative correlation between visitor age and likelihood of being bitten. However, women are bitten significantly more than men. Average age of people bitten also varies between months. Recorded aggression levels are generally low despite no control over animal-visitor interactions, but are much higher than in similar Barbary macaque enclosures in France and Germany. The Gibraltar troop's small home range and high visitor density may explain recorded bite levels. Effective visitor education can significantly lower biting incidence.     

Observations of the mating behavior and dentition of the round stingray,Urolophus halleri

Synopsis The mating behavior and dentition ofUrolophus halleri, the round stingray was examined. Males frequently bite females during the mating period but most male biting does not result in copulation. In bites that do not lead to copulation, males bite the posterior (or occasionally the medial) portion of the females' disc but females often free themselves from these bites. In bites that precede copulation, males bite the anterior portion of the females' disc and females do not struggle to free themselves. Thus, females may exert some form of choice when they are bitten. Mature males have sexually dimorphic dentition that may aid in holding females. A principal component analysis (PCA) showed that in juvenile males, the relative size of the teeth decrease while the relative thickness of the disc increases as body size enlarges; adult males displayed no clear pattern. In adult females, there is a relative decrease in tooth size and increase in relative disc thickness as body size enlarges. The relative increase in females disc thickness in areas where they are bitten may function to minimize the amount of damage due to non-copulatory biting. There is no indication that biting functions to induce female receptivity but it may allow females and males to acquire information about potential mates. Thus, copulatory biting functions to maintain contact during copulation while the function of non-copulatory biting is less clear.     

The implicit rules of combat reflect the evolved function of combat: An evolutionary-psychological analysis of fairness and honor in human aggression

Aggression was a powerful selection pressure for our human ancestors. Aggressive contests would have selected not only for anatomical features (e.g., superior upper-body strength in adult males), but also for behavior-regulation adaptations for the conditional and cost-effective deployment of aggression. Here, we explore two concepts that appear to be part of the neurocognitive suite that regulates aggression. The first is the concept of a “fair fight”, which tags whether an aggressive bout can provide an unbiased estimate of the relative fighting ability of the combatants. The second concept is the “honorability” of a fighter, which tags whether an individual can be trusted to not inflict aggression in excess of what is needed to establish the relative fighting ability of the combatants. Eight predictions were derived from these hypotheses and tested experimentally with vignettes that varied relevant aspects of a fight. The results support the predictions. Fights are perceived as “fair” to the extent that the fighters avoid biased tactics that improve their probability of winning absent superior fighting ability (e.g., not attacking when the opponent is unprepared). Further, fighters are perceived as “honorable” when they minimize the danger to both combatants (e.g., not attacking after the opponent surrenders). We conclude by listing additional implications of the theory.     

Attack and defensive behaviour in the albino rat

Attack of dominant colony males of an albino rat (Rattus norvegicus) strain, on introduced strangers, produced a non-random distribution of bites, with ventral trunk virtually never bitten. Also, vibrissae-contact of attacker and defender interfered with bites to the defender's head and upper back. The specific agonistic reactions of attacking and defending rats appeared to involve strategies based on these limitation on attack: defenders utilized 'boxing' and lying 'on-the-back' behaviour, which interposed ventral trunk and vibrissae between attacker and defender. In turn, the 'lateral display' permitted attackers to circumvent the defender's behaviour. Limitations on attack therefore appeared to underlie the specific agonistic behaviour of both attacking and defending rats.     

Dramatic increase in sea otter mortality from white sharks in California

Although southern sea otters (Enhydra lutris nereis) are not considered prey for white sharks (Carcharodon carcharias), sharks do nonetheless bite sea otters. We analyzed spatial and temporal trends in shark bites on sea otters in California, assessing the frequency of shark bite wounds in 1,870 carcasses collected since 1985. The proportion of stranded sea otters having shark bites has increased sharply since 2003, and white shark bites now account for >50% of recovered carcasses. The trend was most pronounced in the southern part of the range, from Estero Bay to Point Conception, where shark bite frequency has increased eightfold. Seasonal trends were also evident: most shark‐bitten carcasses are recovered in late summer and fall; however, the period of elevated shark bite frequency has lengthened. The causes of these trends are unclear, but possible contributing factors include increased white shark abundance and/or changes in white shark behavior and distribution. In particular, the spatiotemporal patterns of shark‐bitten sea otters match increases in pinniped populations, and the increased availability of marine mammal prey for white sharks may have led to more sharks spending more time in nearshore waters utilized by both sea otters and pinnipeds.     

Does Lateral Presentation of the Palmate Antlers During Fights by Fallow Deer (Dama dama L.) Signify Dominance or Submission?

A central aim of the study of animal communication is to identify the mode and content of information transferred between individuals. The lateral presentation of the antler palm between male fallow deer has been described as either a signal of individual quality or an attempt to avoid fighting. In the first case two phenotypic features have been proposed by which transmission of individual quality may be facilitated. These are antler size and antler symmetry. The alternative hypothesis proposes that the lateral presentation of antlers occurs as a consequence of averting a threatening posture and may signify a reluctance to fight. We examined whether mature fallow deer use lateral palm presentation as a display during fights to indicate antler size and symmetry. We found no relationship between presentation rate of the antler and antler size and symmetry. Furthermore, males did not preferentially present their larger antler to their opponent. We also investigated whether the rate at which males presented antlers laterally during a fight was related to their ability to win the fight. Our results show that the male who performed more presentations during a fight was more likely to lose it. There were behavioural differences in the way in which a bout of presentation ended; subsequent losers tended to turn their body away from their opponent and subsequent winners tended to lower their antlers to an opponent which we interpret as an invitation to continue fighting. We conclude that the lateral palm presentation serves to de-escalate fighting between mature fallow deer. It is not a mechanism by which to communicate individual quality but rather an indication that a male is less committed to continuing investment in the current contest.     

Indirect genetic effects contribute substantially to heritable variation in aggression-related traits in group-housed mink (Neovison vison)

Background

Since the recommendations on group housing of mink (Neovison vison) were adopted by the Council of Europe in 1999, it has become common in mink production in Europe. Group housing is advantageous from a production perspective, but can lead to aggression between animals and thus raises a welfare issue. Bite marks on the animals are an indicator of this aggressive behaviour and thus selection against frequency of bite marks should reduce aggression and improve animal welfare. Bite marks on one individual reflect the aggression of its group members, which means that the number of bite marks carried by one individual depends on the behaviour of other individuals and that it may have a genetic basis. Thus, for a successful breeding strategy it could be crucial to consider both direct (DGE) and indirect (IGE) genetic effects on this trait. However, to date no study has investigated the genetic basis of bite marks in mink.

Result and discussion

A model that included DGE and IGE fitted the data significantly better than a model with DGE only, and IGE contributed a substantial proportion of the heritable variation available for response to selection. In the model with IGE, the total heritable variation expressed as the proportion of phenotypic variance (T²) was six times greater than classical heritability (h²). For instance, for total bite marks, T² was equal to 0.61, while h² was equal to 0.10. The genetic correlation between direct and indirect effects ranged from 0.55 for neck bite marks to 0.99 for tail bite marks. This positive correlation suggests that mink have a tendency to fight in a reciprocal way (giving and receiving bites) and thus, a genotype that confers a tendency to bite other individuals can also cause its bearer to receive more bites.

Conclusion

Both direct and indirect genetic effects contribute to variation in number of bite marks in group-housed mink. Thus, a genetic selection design that includes both direct genetic and indirect genetic effects could reduce the frequency of bite marks and probably aggression behaviour in group-housed mink.     

The effect of differences in herbage height on the grazing behaviour of lactating Bennett's wallabies (Macropus rufogriseus rufogriseus)

The grazing behaviour of lactating Bennett's wallabies was studied on a number of different pasture types. Increases in mean sward height resulted in a greatly reduced bite rate and an increase in the search time per bite. All wallabies showed a diurnal rhythm in grazing activity irrespective of habitat type, with least grazing activity at midday and most at night. Animals maintained on very short grass swards compensated for the reduced herbage mass by extending their grazing activity into the midday period. Lactating animals grazed for longer, had higher biting rates and a greater number of estimated bites per day than non-lactating wallabies (17,700 vs. 7600 bites per day, respectively). In general, the response of wallabies to changes in herbage availability is similar to domestic ruminants, although wallabies may be able to graze for longer each day than ruminants.     

An Analysis of Some Predatory Behaviour Patterns in Four Species of Carnivorous Marsupials (Dasyuridae), with Comparative Notes on the Eutherian Cat Felis catus

Two aspects of predatory behaviour in five species of carnivorous mammals were studied: four species (Dasyurus viverrinus, Dasyurus hallucatus, Dasyuroides byrnei and Phascogale tapoatafa) of a group of Australian marsupials, Dasyuridae, and an eutherian, the domestic cat, Felis catus. All data were collected from captive animals in laboratory conditions. Using sequences of predatory behaviour recorded on movie film, two aspects of predation were compared: (a) attack strategy, that is, the behavioural patterns leading up to biting the prey, and (2) head shaking movements used during killing. All individual predators of all species but Dasyuroides byrnei exhibited avoidance of attacking prey from the front. Indeed, two of the four individual Dasyuroides used not only did not avoid frontal attack but selected to do so even when attacks from the rear or side were possible (e.g., the prey sat unmoving in the centre of the enclosure). Frontal attacks by Dasyuroides involved the use of the forepaws to grasp and pin prey, and the directing of killing bites to the head. These two behaviour patterns are also present in the other three species of dasyurids. Therefore, the frontal attack employed by this species does not involve the use of novel behaviour patterns. Analysis of head shakes revealed two basic forms. From a downward pointing position the head was rotated in one of two ways: the snout traversed an arc in space, as seen in Felis catus and Dasyurus hallucatus, or the sagittal crest traversed an arc in space, as seen in the other three species of dasyurids. When the prey is held down by the forepaws, either form of head shake enhances penetration of the canines into the prey, whereas, when not held down by the forepaws, both forms of head shake can disorient prey, enabling subsequent killing bites to be applied.     

Foraging ecology of Cookiecutter Sharks (<Emphasis Type="Italic">Isistius brasiliensis</Emphasis>) on pelagic fishes in Hawaii,inferred from prey bite wounds

The Cookiecutter Shark (Isistius brasiliensis) is an ecto-parasitic predator of numerous large pelagic fish and mammals. However, little is known of its foraging ecology due to its elusive foraging tactics in the pelagic environment. We used bite scar patterns on pelagic fishes landed at the Honolulu Fish Auction to assess some of the Cookiecutter Shark foraging habits. Swordfish (Xiphias gladius) had the greatest percentage of bites (87.9 ± 25.0% of individuals had healed scars) followed by Opah (Lampris guttatus, 33.0 ± 8.3% of individuals). Most fish with scars only had one Cookiecutter Shark bite per individual with the exception of Swordfish, which often had >5 bites per individual. Furthermore, Swordfish had a higher proportion of healed bite scars meaning they had been attacked while free-swimming. Seasonal changes in the probability of hooked fish being bitten by sharks were apparent for Swordfish, Bigeye Tuna and Opah. Based on bite scar diameter, larger Cookiecutter Sharks may preferentially attack Swordfish rather than the other species of pelagic fish. When taken in conjunction with diving behavior of pelagic fish, and fishing depths, the results add further support to the hypothesis that Cookiecutter Sharks perform diel vertical migrations.     

Startle durations reveal visual assessment abilities during contests between convict cichlids

In animal contests, the widespread ability of contestants to assess their opponents’ resource holding potential (RHP) relative to their own, termed mutual assessment, has recently been questioned. It is possible that each contestant may only have information about its own abilities or state, incurring costs up to a particular threshold then giving up, termed self-assessment. We used a technique that provides a measure of fight motivation to discriminate between different assessment models during aggressive encounters between male convict cichlids, Amatitlania nigrofasciata. A novel stimulus was applied to cause a startle response in one contestant of an aggressively interacting, size mis-matched pair, whereby the animal temporarily stops fighting. The time taken to resume the contest has been verified to provide a measure of the motivation to fight, from which it is possible to infer if any visual information concerning opponent asymmetries has been gathered. The data showed support for two differing types of assessment. There was some support for self-assessment, with startle duration being negatively related to own size, and, in a later trial series some support for an opponent only assessment strategy, with startle duration being positively related to opponent size. These results are consistent with individuals learning to use visual information about opponents when deprived of other sensory cues. Evidence within a trial supporting visual mutual assessment was lacking and possible reasons for this are discussed.     

Connecting behaviour and performance: the evolution of biting behaviour and bite performance in bats

Variation in behaviour, performance and ecology are traditionally associated with variation in morphology. A neglected part of this ecomorphological paradigm is the interaction between behaviour and performance, the ability to carry out tasks that impact fitness. Here we investigate the relationship between biting behaviour and performance (bite force) among 20 species of ecologically diverse bats. We studied the patterns of evolution of plasticity in biting behaviour and bite force, and reconstructed ancestral states for behaviour and its plasticity. Both behavioural and performance plasticity exhibited accelerating evolution over time, and periods of rapid evolution coincided with major dietary shifts from insect‐feeding to plant‐feeding. We found a significant, positive correlation between behavioural plasticity and bite force. Bats modulated their performance by changing their biting behaviour to maximize bite force when feeding on hard foods. The ancestor of phyllostomids was likely a generalist characterized by high behavioural plasticity, a condition that also evolved in specialized frugivores and potentially contributed to their diversification.     

Dog bites in humans and estimating human rabies mortality in rabies endemic areas of Bhutan

Background

Dog bites in humans are a public health problem worldwide. The issues of increasing stray dog populations, rabies outbreaks, and the risk of dogs biting humans have been frequently reported by the media in Bhutan. This study aimed to estimate the bite incidence and identify the risk factors for dog bites in humans, and to estimate human deaths from rabies in rabies endemic south Bhutan.

Methods

A hospital-based questionnaire survey was conducted during 2009–2010 among dog bites victims who visited three hospitals in Bhutan for anti-rabies vaccine injection. Decision tree modeling was used to estimate human deaths from rabies following dog bite injuries in two rabies endemic areas of south Bhutan.

Results

Three hundred and twenty four dog bite victims were interviewed. The annual incidence of dog bites differed between the hospital catchment areas: 869.8 (95% CI: 722.8–1022.5), 293.8 (240–358.2) and 284.8 (251.2–323) per 100,000 people in Gelephu, Phuentsholing and Thimphu, respectively. Males (62%) were more at risk than females (P<0.001). Children aged 5–9 years were bitten more than other age groups. The majority of victims (71%) were bitten by stray dogs. No direct fatal injury was reported. In two hospital areas (Gelephu and Phuentsholing) in south Bhutan the annual incidence of death from rabies was 3.14 (95% CI: 1.57–6.29) per 100,000 population. The decision tree model predicted an equivalent annual incidence of 4.67 (95% CI: 2.53–7.53) deaths/100,000 population at risk. In the absence of post exposure prophylaxis, the model predicted 19.24 (95% CI: 13.69–25.14) deaths/year in these two areas.

Conclusions

Increased educational awareness of people about the risk of dog bites and rabies is necessary, particularly for children in rabies endemic areas of Bhutan.     

Seasonal,demographic and density‐related patterns of contact between Tasmanian devils (Sarcophilus harrisii): Implications for transmission of devil facial tumour disease

Abstract Devil facial tumour disease (DFTD), is an emerging infectious cancer thought to be spread by biting. It is causing ongoing, severe population decline of the Tasmanian devil (Sarcophilus harrisii), the largest surviving marsupial carnivore and there are concerns that DFTD may lead to extinction of the devil. Whether extinction is likely depends on contact rates and their relationship to host density. We investigated contact rates using two different datasets. The first consisted of field observations of contact and biting behaviour around prey carcasses and, the second was a 3‐year longitudinal series of injuries in a marked devil population. During feeding interactions at carcasses, contact rates were significantly positively associated with population density and subadults delivered more bites than adult males and females. Injuries from the marked devil population did not differ between adult males and females. In two of the three years, penetrating biting (resulting in injury) increased markedly during the mating season and was more frequent in adults than in subadults. Among injured devils with wounds penetrating the dermal layer, adults were more frequently bitten in the head (the location of primary tumours) in the mating season than in other seasons, and had more head bites than subadults. Our results suggest that the mating season may be the key period for disease transmission. If most penetrating bites occur during mating interactions, DFTD transmission is likely to be frequency dependent, which means that there would be no threshold host density for disease persistence, and disease‐induced extinction is possible.     

Men’s Interest in Allying with a Previous Combatant for Future Group Combat

Intra- and intergroup conflict are likely to have been recurrent features of human evolutionary history; however, little research has investigated the factors that affect men’s combat alliance decisions. The current study investigated whether features of previous one-on-one combat with an opponent affect men’s interest in allying with that opponent for future group combat. Fifty-eight undergraduate men recruited from a psychology department subject pool participated in a one-on-one laboratory fight simulation. We manipulated fight outcome (between-subjects), perceived fighter health asymmetry (within-subjects), and the presence of a witness (within-subjects) over six sets of five rounds of fighting. Following each set, we asked men how interested they would be in allying with their opponent for future group combat. We found that men were more interested in allying with their opponent for future group combat if their opponent won the fight or if a witness was present, but perceived fighter-health asymmetry did not affect men’s decision to ally with their opponent. Exploratory analyses revealed a two-way interaction between fight outcome and the presence of a witness, such that winners without a witness present expressed less interest in allying with their opponent for future group combat. Our findings suggest that men attend to the benefits of allying with a man who has demonstrated relatively superior fighting ability. Alliance with a previous opponent for group combat may vary with the relationship value of the opponent and the utility of demonstrating cooperativeness to third-party observers. These findings inform our understanding of coalition formation.     

Exploration of Perceptions of Dog Bites among YouTube™ Viewers and Attributions of Blame

Dog bites are a human public health and dog welfare problem. This qualitative study is the first to use YouTube^? to examine how viewers perceive risk of, and attribute blame for, dog bites. Comments underneath 10 videos, chosen to represent a diversity of dog-bite scenarios, were analyzed inductively using thematic analysis. Six themes emerged: 1) Commentators thought that dogs are inherently good-natured but wild animals and emphasized how dogs try to avoid biting people; 2) all recognized breeds of dogs were stereotyped and breed stereotypes were used to shift the blame away from the dog and onto a bite victim, unless the dog identified in a video was a pit bull type. The dog was often blamed in such case; 3) It was argued that a breed limits the extent to which a dog can be trained and controlled; 4) Owners/handlers were often blamed for bites due to their inability to control the dog, and commentators identified the need for appropriate training and socialization in order to control dogs and reduce bite risk; 5) Bite victims were also blamed for the bites when their behavior was perceived as provoking a dog. Although children's behavior was identified as causing a risk, parents of children bitten in the videos were blamed for bites instead due to their approach to child supervision; 6) Bites in a range of contexts, such as play or when viewers thought that the victim's behavior provoked a dog, were seen as well-de-served and normal. It was concluded that although comments on publicly available videos need to be interpreted with caution due to a self-selection bias, their analysis can help to identify attitudes and perceptions towards risk around dogs that could aid bite prevention interventions and policies.