The impact of exhibit type on behaviour of caged and free-ranging tamarins

The lack of appropriate stimuli associated with captive environments has been documented to cause several behavioural and physiological issues in captive species, including loss of natural behaviours, psychopathologies and decreased reproductive success. Providing free-ranging, naturalistic exhibits that replicate elements of a species' natural environment is advocated as a means of promoting and preserving the natural behavioural repertoire in captive species. Exhibition of natural behaviour is considered beneficial to conservation in terms of animal health and welfare, reintroduction success, education and research. This study assessed differences in behaviour of emperor and pied tamarins housed in free-ranging and caged exhibits at Durrell Wildlife Park to determine the impact of exhibit type. Free-ranging tamarins were expected to exhibit a repertoire of behaviours more similar to that of wild tamarins based on their access to a more naturalistic and complex environment. Data was collected on a variety of behaviours, including activity, substrate use and communication, using instantaneous and one-zero sampling at 30 s intervals. Findings indicated that both free-ranging and caged tamarins exhibited natural behaviours; however, there were significant differences in mean rates of behaviours between conditions. Free-ranging tamarins exhibited significantly higher rates of locomotion (emperors: P < 0.001; pieds: P < 0.001), long calls (pieds: P = 0.019) and alarm calls (emperors: P = 0.012), and displayed competent use of the environment in terms of natural substrate use (emperors: P < 0.001; pieds: P = 0.007) and interspecific interactions. Caged tamarins exhibited significantly higher rates of affiliative (emperors: P = 0.001; pieds: P = 0.026) and agonistic (emperors: P = 0.003) intraspecific interactions and time spent in contact (emperors: P = 0.048; pieds: P = 0.043), which was largely attributed to spatial restrictions imposed by caged exhibits. This study, consistent with existing literature, indicated that the free-ranging exhibit was conducive to the expression of a behavioural repertoire more similar to that of wild tamarins. This was probably a result of the increased behavioural opportunities available in the free-ranging exhibit, highlighting their importance in promoting wild-type behaviours. However, some mean rates of behaviour were still noticeably less than those documented in wild counterparts. Methods to further promote natural behaviours in both exhibits are recommended to facilitate ex situ and in situ conservation efforts.