To eat, or not to eat: A phantom decoy affects information-gathering behavior by a free-ranging mammalian herbivore

When foraging, making appropriate food choices is crucial to an animal's fitness. Classic foraging ecology theories assume animals choose food of greatest benefit based on their absolute value across multiple dimensions. Consequently, poorer options are considered irrelevant alternatives that should not influence decision-making among better options. But heuristic studies demonstrate that irrelevant alternatives (termed decoys) can influence decisions of some animals, indicating they use a relative rather than absolute evaluation system. Our aim was to test whether a decoy influenced the decision-making process – i.e. information-gathering and food choice – of a free-ranging mammalian herbivore. We tested swamp wallabies, Wallabia bicolor, comparing their behavior towards, and choice of, two available food options over time in the absence or presence of the decoy. We used a phantom decoy—unavailable option—and ran two trials in different locations and seasons. Binary preferences (decoy ..., ,