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Many test series have been developed to assess dog temperament and aggressive behavior, but most of them have been criticized for their relatively low predictive validity or being too long, stressful, and/or problematic to carry out. We aimed to develop a short and effective series of tests that corresponds with (a) the dog's bite history, and (b) owner evaluation of the dog's aggressive tendencies. Seventy-three pet dogs were divided into three groups by their biting history; non-biter, bit once, and multiple biter. All dogs were exposed to a short test series modeling five real-life situations: friendly greeting, take away bone, threatening approach, tug-of-war, and roll over. We found strong correlations between the in-test behavior and owner reports of dogs' aggressive tendencies towards strangers; however, the test results did not mirror the reported owner-directed aggressive tendencies. Three test situations (friendly greeting, take-away bone, threatening approach) proved to be effective in evoking specific behavioral differences according to dog biting history. Non-biters differed from biters, and there were also specific differences related to aggression and fear between the two biter groups. When a subsample of dogs was retested, the test revealed consistent results over time. We suggest that our test is adequate for a quick, general assessment of human-directed aggression in dogs, particularly to evaluate their tendency for aggressive behaviors towards strangers. Identifying important behavioral indicators of aggressive tendencies, this test can serve as a useful tool to study the genetic or neural correlates of human-directed aggression in dogs.

Both animal and human studies suggest that in adulthood, plasma vasopressin level correlates well with anxiety. Little is known about the mood regulation during the perinatal period. Here, we aim to investigate the influence of vasopressin on anxiety during the early postnatal age. As a sign of distress, rat pups emit ultrasonic vocalizations (USVs) when they are separated from their mother. This USV was detected in 7- to 8-day-old vasopressin-deficient Brattleboro pups, and they were compared to their heterozygote littermates and wild-type pups. The results were confirmed by V1b antagonist treatment (SSR149415 10 mg/kg ip 30 min before test) in wild-types. Chlordiazepoxide (3 mg/kg ip 30 min before test)-an anxiolytic-was used to test the interaction with the GABAergic system. At the end of the test, stress-hormone levels were measured by radioimmunoassay. Vasopressin-deficient pups vocalized substantially less than non-deficient counterparts. Treatment with V1b antagonist resulted in similar effect. Chlordiazepoxide reduced the frequency and duration of the vocalization only in wild-types. Reduced vocalization was accompanied by smaller adrenocorticotropin levels but the level of corticosterone was variable. Our results indicate that the anxiolytic effect of vasopressin deficiency (both genetic and pharmacological) exists already during the early postnatal age. Vasopressin interacts with the GABAergic system. As mood regulation does not go parallel with glucocorticoid levels, we suggest that vasopressin might have a direct effect on special brain areas.