Prey naïveté and the anti-predator responses of a vulnerable marsupial prey to known and novel predators

Abstract

Prey may recognize and respond to predatory cues based on a period of co-evolution or life experience with a predator. When faced with a novel predator, prey may be naïve to the threat posed and/or unable to respond effectively, making them highly susceptible to predation. Burrowing bettongs (Bettongia lesueur) are one such species whose naïveté towards introduced predators has contributed to their extinction from mainland Australia. Here, we asked whether bettongs that were predator-naïve and bettongs which had been exposed to feral cats (Felis catus) for up to 2 years could discriminate between odors of a predator with which they shared no evolutionary history (feral cats), a predator with which they share a deep evolutionary history (Tasmanian devil—Sarcophilus harrisii), a novel herbivore (guinea pig—Cavia porcellus), and procedural control (a towel moistened with deionized water). We deployed scents at foraging trays and filmed bettongs’ behavior at the trays. Predator-naïve bettongs’ latency to approach foraging trays and behavior did not differ between scents. Cat-exposed bettongs increased their latency to approach in the presence of animal scents compared with control, and approached predatory scents slowly and cautiously more often than herbivore and procedural control scents. Taken together, these results suggest that bettongs have not retained anti-predator responses to Tasmanian devils after 8000 years of isolation from mammalian predators but nevertheless show that bettongs exposed to predators are more wary and may be able to generalize predator response using olfactory cues.