Evolutionary Aspects of the Use of Predator Odors in Antipredator Behaviors of Lumholtz’s Tree-Kangaroos (Dendrolagus lumholtzi)

In multi-predator systems with different predator ‘archetypes’, prey have an advantage when applying ‘archetype’-specific responses. However, antipredator responses can be lost or modified during times of ‘relaxed predation selection’. As a consequence, prey may become vulnerable when novel predators are introduced into their environments. This study investigates whether the Lumholtz’s tree-kangaroo (LTK) (Dendrolagus lumholtzi), an arboreal folivore marsupial of rainforests in North Queensland, Australia, (1) recognizes odor cues from arboreal and terrestrial predators, (2) exhibits archetype-specific antipredator responses to them, and (3) is able to transmit archetype-specific antipredator responses to novel predators of similar archetype. Five captive LTKs were exposed to lavender oil as neutral odor, fecal material from an extant arboreal predator, the amethystine python (Morelia amethystine), from two novel terrestrial predators, the domestic dog (Canis lupus familiaris) and the dingo (Canis lupus dingo), and a control odor (water). All subjects showed an increase in durations and frequencies of vigilance, and a decrease in the duration of comfort behaviors when exposed to the fecal material compared to the control odor, but not when the neutral odor was presented. This suggests that the presented fecal material is associated with predatory threats. Subjects increased duration and frequency of their movements in trials with fecal material from a python and a dingo, but not in trials with fecal material from a dog or the neutral odor which indicates that tree-kangaroos do not respond differently to arboreal and terrestrial predators. This conclusion is discussed with respect to the relatively recent descent of tree-kangaroos from rock-wallabies at a time when its ancient terrestrial predators became extinct, and with respect to reported fatalities of tree-kangaroos when encountering domestic dogs or dingoes.