Condition-dependent responses to risk in a small mammal

Animal responses to risky situations are shaped by both environmental (external) cues and internal states such as body condition. Recent meta-analyses indicate that individuals in better condition take fewer risks, consistent with the idea that they protect their assets. However, these results rely mostly on short-term, standard laboratory assessments of threat response. Consequently, it remains unclear whether variation in condition influences risk-taking consistently across different ecological contexts. Here, we address this by testing whether house mice from high- or standard-quality food environments, and mice of different weights (used as a proxy for condition), vary in their risk-taking behaviour across two scenarios. First, we quantified foraging behaviour in low- and high-risk areas in the absence of predation cues. We then introduced predator stimuli to assess how foraging changed under increased perceived threat. Overall, we aimed to determine whether the effect of risk on foraging depended on diet quality and body mass. Mice originating from the high-quality food environment reduced foraging in the high-risk area under predation cues significantly more than those from standard-quality environments. In contrast, heavier individuals, irrespective of food quality, foraged less and for shorter periods in the high-risk area. Last, when predation cues were introduced, these heavier mice increased their foraging effort in the high-risk area but did not spend more time there. These findings indicate condition-dependent responses to risk and support core predictions of the asset-protection hypothesis. Importantly, they highlight that different traits related to individual state or condition may shape different responses to ecological unpredictability, such as predation risk. This variation as a function of different variables related to the state warrants further investigation.