Saliva collection using a swab has recently been used to check the stress levels of dogs and can be used in the near future for diagnosing stress in dogs at animal hospitals. However, a suitable technique for collecting saliva from small dogs has not yet been established, despite these being the most popular pets in Japan. Therefore, the objective of this study was to investigate whether the swab technique can be used to collect the required amount of saliva for analysis from small dogs without causing excessive stress. Saliva was collected three times from five small and two medium-sized dogs using a swab, and the salivary cortisol concentration, behavioral response of the dog during saliva collection, and subjective evaluation of the dog’s stress level by the saliva collector and the restrainer of the dog were used as stress indicators. We found that the required amount of saliva (median = 0.35ml) for analysis was collected from all seven dogs. Furthermore, the average salivary cortisol concentration was 0.14μg/dl, and the average frequencies with which each dog licked itself and lifted its paw during the collection were 7.0 and 2.8 times, respectively, indicating that the dogs were not experiencing any severe stress. This was further supported by the subjective evaluation of the dogs’ stress levels by the saliva collector and the restrainer of dogs. Thus, our results suggest that the collection of saliva using a swab is also suitable in small dogs.

The objective of the present study was to obtain basic information on the potential of geese as biological control agents for weeds in agricultural fields. Taste responses of geese to sweet (sucrose), salty (sodium chloride), sour (citric acid monohydrate), bitter (quinine hydrochloride), and umami (monosodium glutamate) taste solutions were studied during the two-choice preference tests. The aforesaid substances were dissolved in tap water to create 11 stepwise test solutions by doubling the concentrations. Percentage of intake of the test solutions to total fluid at each concentration was defined as the preference index. A preference index above 60.3% was defined as the preference zone, below 39.7% was the rejection zone, and between 39.7% and 60.3% was the nondiscrimination zone using the χ²-test (P < 0.05). Geese showed no　preference and rejection to the sucrose solution between 0 and 20% concentration. In contrast, they rejected concentrations above 2.5, 0.32, 0.04, and 5% of sodium chloride, citric acid monohydrate, quinine hydrochloride, and monosodium glutamate solutions, respectively. In conclusion, geese showed no preference to any taste of sweet, salty, sour, bitter, and umami; however, they did aversively respond to the bitter solution at lower concentration levels compared to the sweet, salty, sour, and umami solutions. Therefore, geese are more sensitive to bitter than to sweet, salty, sour, and umami, indicating that they are selective about their grazing diet which is based on the taste.

We investigated whether jungle crows can discriminate facial expressions using photographs of human faces in a two-alternative discrimination task. Crows were first trained to discriminate between two sets of photographs of different individuals, one smiling and the other with neutral expression. Then, crows were tested with two sets of novel photographs one smiling and the other with neutral expression. Our result showed that four out of the six crows selected the novel smiling faces significantly more often than expected by chance. In the subsequent tests, where training stimuli were presented to the crows showing same facial expression, both smiling and both neutral, all crows significantly discriminated the previously rewarded identity. However, all crows failed to discriminate the smiling face when an individual face used in training varied only in its emotional expression. These results suggest that crows can be trained to discriminate different individuals smiling faces from neutral expressions and transfer smiling expression to novel identities. In addition, although discrimination of identity was not affected by variation in emotional expression, discrimination of emotional expression was poor when using same identity; supporting the shared ability of asymmetrical pattern of identity and emotion processing in human and non-human animals.