Quantifying the influence of cut tree branches on zoo giraffe behavior during and post browsing: A case study on five animals and four tree species

The nutrition of captive species profoundly affects their physical, behavioral, and psychological wellbeing. Determining a species’ ideal zoo diet remains challenging, necessitating assessment of an animal’s responses to their diet to establish best practices, including any effects on behaviors. This study investigates the behavioral responses of five female giraffes ( Giraffe camelopardalis ) to browse from four tree species (willow, Salix caprea ; hawthorn, Crataegus monogyna ; hazel, Corylus avellana ; oak, Quercus robur ). This study aimed to assess the effect of browse species on giraffe activity and to identify which of these species was most associated with performance of key welfare indicators. Given this species’ adaptations to foraging on spinose (i.e., thorny) trees, we predicted that hawthorn would have the largest effect on giraffe behavior. Focal sampling of individual giraffes was conducted, with equal repetitions for each browse species, across spring and summer 2021 and 2022 at Marwell Zoo. Giraffes were observed for an hour with browse, followed by an additional hour after a 30-minute pause to quantify post-browsing behaviors. Results suggest that willow increased overall browsing time, while oak elicited prolonged interaction with initial browse branches. Willow promoted the highest bark stripping and bite counts, while oak and willow increased time ruminating. Contrary to expectation, hawthorn, with its thorny defences, did not significantly extend browsing or rumination. Social context also influenced browsing behavior with heightened browsing activity occurring when giraffe browsed with other species present. While a case study of four tree species at one zoo, our results show the importance of measuring and assessing animal choice and preferences (regarding their engagement with husbandry) to underpin best practice approaches to care and welfare. • Captive giraffes differ in the amount of time spent browsing different species of tree • Time on ruminating, foraging and further browsing was promoted by oak (Quercus rober) • Bites and chews when browsing were influenced by environmental and social factors • Regular monitoring of behavior and browse intake would support better practice husbandry