Human and nonhuman animals show personality: temporal and contextual consistency in behavior patterns that vary among individuals. In contrast to most other species, personality of chimpanzees, Pan troglodytes, has mainly been studied with non-behavioral methods. We examined boldness, exploration tendency, persistence and tool-orientation in 29 captive chimpanzees using repeated experiments conducted in an ecologically valid social setting. High temporal repeatability and contextual consistency in all these traits indicated they reflected personality. In addition, Principal Component Analysis revealed two independent syndromes, labeled exploration-persistence and boldness. We found no sex or rank differences in the trait scores, but the scores declined with age. Nonetheless, there was considerable inter-individual variation within age-classes, suggesting that behavior was not merely determined by age but also by dispositional effects. In conclusion, our study complements earlier rating studies and adds new traits to the chimpanzee personality, thereby supporting the existence of multiple personality traits among chimpanzees. We stress the importance of ecologically valid behavioral research to assess multiple personality traits and their association, as it allows inclusion of ape studies in the comparison of personality structures across species studied behaviorally, and furthers our attempts to unravel the causes and consequences of animal personality.

Behavioural disorders are a major reason for euthanasia and sheltering of pet dogs. The prevention and treatment of behavioural disorders requires a better understanding of the underlying causes. Early life experiences, such as maternal care, attachment and socialisation, have long lasting and serious consequences for the behavioural and physiological development of an individual. The complex interplay between these factors is likely to have consequences for the future dog-owner bond and the vulnerability to develop behavioural disorders. Here, we summarise the current literature on the interactions between maternal care, attachment formation, and the sensitive socialisation period and their potential consequences on adult dog behaviour. Based on the findings we highlight gaps in knowledge and provide suggestions for future research which are necessary to formulate recommendations for pet dog breeding and socialisation.

19Previous research suggested that 16--week old dog pups, but not wolf pups, 20show attachment behaviour to a human caregiver. Attachment to a caregiver in dog 21 pups has been demonstrated by differential responding to a caregiver compared to 22 a stranger in the Ainsworth Strange Situation Test. We show here that 3--7 week old 23 wolf pups also show attachment--like behaviour to a human caregiver as measured 24 by preferential proximity seeking, preferential contact, and preferential greeting to 25 a human caregiver over a human stranger in a modified and counterbalanced 26 version of the Ainsworth Strange Situation Test. In addition, our results show that 27 preferential responding to a caregiver over a stranger is only apparent following 28 brief isolation. In initial episodes, wolf pups show no differentiation between the 29 caregiver and the stranger; however, following a 2--min separation, the pups show 30 proximity seeking, more contact, and more greeting to the caregiver than the 31 stranger. These results suggest intensive human socialization of a wolf can lead to 32 attachment--like responding to a human caregiver during the first two months of a 33 wolf pup's life. 34