Animal personality drives individual dietary specialisation across multiple dimensions in a mammalian herbivore

Animal personality influences how individuals perceive and react to different stimuli, such as food quality and predation risk, thereby shaping foraging behaviour. As a consequence, animal personality is predicted to influence the diet and dietary specialisation of individuals within a population, but animal personality and dietary specialisation have yet to be linked. Here, we tested whether individual diet and dietary specialisation are a function of animal personality, using an arboreal herbivore, the common brushtail possum, as a model species. We hypothesised that proactive individuals have more diverse foraging opportunities than reactive individuals. We therefore predicted that proactive animals (more exploratory, bold and more active) would be less specialised, with a broader and higher quality diet than their reactive counterparts. We quantified the personality traits and dietary niche using proportional similarity index and specialisation categories of possums (n = 30) in a population flanking native eucalypt woodland and residential gardens in suburban Sydney, Australia. We found that personality traits were related to the breadth and quality of the realised diets of individual possums. As predicted, proactive individuals had a broad, high‐quality diet with less individual dietary specialisation than reactive individuals. Highly exploratory individuals had a more diverse diet than less exploratory individuals, and bold individuals were more likely than shy individuals to consume plants on the ground. Our study demonstrates an important link between animal personality and individual dietary specialisation. The finding that the personality of individuals is associated with different diet choices within the same landscape is fundamentally significant. First, personality as a driver of niche partitioning likely reduces within‐species competition and hence could contribute to adaptive capacity. Second, the strength of ecological processes arising from interactions (e.g. predator–prey and plant–herbivore interactions) could differ among individuals according to their personality traits. Our findings are also relevant for effectively managing both threatened native and invasive species. Management strategies will be improved by incorporating knowledge of individual traits and their ecological consequences, plus the ecological context of food‐ and fear‐scapes. A free Plain Language Summary can be found within the Supporting Information of this article.