Risk sensitivity in female beluga whales (Delphinapterus leucas).

Abstract

The world is full of uncertainty, often requiring decisions that involve unknown outcomes. Responses to uncertainty, or risk, have been widely studied, revealing both species-level and individual differences. Risk studies have focused on a few key species, so to increase taxon diversity, we investigated the risk sensitivity of four female beluga whales (Delphinapterus leucas) living under human care. We presented them with two options that had identical mean value but differed in their respective variability. The safe option provided four fish every time it was selected, and the risky option provided either zero or eight fish with equal probability. Belugas' preferences varied, with two whales preferring the safe option and two whales preferring the risky option. Testing across morning and afternoon sessions revealed that satiation, assumed to be higher in the afternoon due to feeding schedules, exacerbated existing tendencies toward the safe option in two whales, but did not change any of the belugas' overall preferences. In addition, whales maintained their preferences irrespective of what they had received on the previous trial. Therefore, within individuals, neither short (previous trial) nor longer (time of day) term contexts influenced individuals' preferences, suggesting that these differences were stable. Our results emphasize the importance of considering individual differences in animal decision-making. (PsycInfo Database Record (c) 2026 APA, all rights reserved).