An investigation into social relationships and social structure in UK and Irish zoo elephant herds

Appropriate social groups in zoo-housed animals can enhance welfare, longevity, health status and reproductive success of individuals, and consequently zoo populations. However, inappropriate social groups can be detrimental to individual welfare states. Suboptimal social housing in zoo animals has been linked with increased prevalence of stereotypies, increased aggression and reduced reproductive success. In the wild, elephants predominantly live in herds of related individuals and have a fission-fusion social group structure (i.e. group size and structure fluctuates over time). Concerns have been made over whether elephants in zoos can be kept in appropriate social groups which meet their complex needs. Social interactions have been identified as an indicator of positive welfare in zoo elephants. The aim of this thesis was to ascertain the effect of individual and zoo-level factors including individual personality on herd interactions and social structure, and to gauge the level of change in herd dynamics over a year. Behavioural data were collected over 12 months for each study zoo (January 2016 – February 2017). Subjects were 10 African (1 male: 9 female) and 22 Asian (3 male: 19 female) elephants housed at 7 zoos and safari parks in the UK and Ireland. Methods employed combined extensive behavioural observations (live and video), social network analysis and keeper questionnaires to quantify data on social interactions and personality. Social interactions were considered to be either positive (e.g. touching with the trunk or walking towards another individual) or negative (e.g. hitting with the trunk or displacement) and were further sub-divided into physical and non-physical interactions. Key demographic factors that could affect social interactions and relationships in zoo elephants, and therefore contributing to cohesive, successful social groups were identified. The results provided evidence for complex herd structures which may not be static over time. Personality was reliably rated by elephant keepers. A sociable personality component was identified from the personality assessment. Level of sociability of elephants as rated by keepers was related positively to frequency of positive interactions given and negatively to frequency of negative interactions given. Interactions in the study herds and within dyads were affected by age, relatedness to others, species, the presence of calves in the group and individual personality. Calves were central to social interactions in many of the herds, interacting with all members of the group and engaging in more physical interactions than older elephants. The presence of positive social interactions and absence of extreme aggression in the study herds is indicative of current successful social group management of elephants in UK and Irish zoos. This research has identified factors that may contribute to successful social housing of zoo elephants. Based on the results, recommendations for changes to practice and areas for future research are made that will continue to advance knowledge and enhance long-term zoo elephant welfare. Of utmost importance is developing a means of assessing social compatibility between individuals, to facilitate such a measure in long-term welfare assessment