Temperament assessment of black (Diceros bicornis) and white (Ceratotherium simum) rhinos using keeper temperament surveys and novel object tests.

Abstract

Ex situ conservation of African rhinoceros is essential for their preservation, and characterization of temperament could be useful for managing their wellbeing. Here, the temperaments of 49 black (Diceros bicornis, BR) and 125 white (Ceratotherium simum, WR) rhinos in North American institutions were assessed using keeper temperament surveys. Median keeper ratings on 12 behaviors were clustered by PCAs into temperament profiles related to bold/fearful, active/inactive and anthrophilic/-phobic traits for BR and WR, and reactive/stoic traits for WR. Novel object (rope basket) tests were conducted on 32 BR and 66 WR to measure individual temperaments. Proportion of time active and stimulated, frequency of interactions, and latency to approach the basket were analyzed. Statistical models were used to determine associations of demographic and environmental factors with the expression of temperament. Spearman's correlations were used to assess the relationship and validity between temperament assessments. The survey temperament profiles indicated that males of both species were more active than females, and activity declined with age in WR (p < 0.05). Age, temperature and enclosure size were significantly associated with behaviors in BR and WR during the novel object test, whereas sex, calf presence and social housing additionally had significant associations with WR behaviors. Younger BR and WR and individually-housed WR were more likely to engage in novel situations (p < 0.05). Personality traits of active/inactive, anthrophilic/-phobic, bold/fearful, exploratory/avoidant, and sociable/aggressive with conspecifics were correlated in both assessments (p < 0.05) reinforcing the reliability of temperament surveys and novel object tests for assessing rhino temperament. These assessments measured rhinos' tendency towards fearfulness and exploration. Understanding temperament could aid managers making decisions related to training, housing, or other aspects to minimize aversive experiences. Consideration of a rhino's natural activity and comfort with humans could enable tailoring expectations for daily behaviors, interactions with enrichment, conspecifics, and people to promote positive mental states and wellbeing.