Cave-dwelling bats do not avoid TMT and 2-PT - components of predator odour that induce fear in other small mammals.
Recognition and avoidance of predators is fundamental for the survival of prey animals. Here we conducted the first study assessing chemosensory predator recognition in cave-dwelling bats. We used a Y-maze approach to test the reaction of greater mouse-eared bats (Myotis myotis) to two synthetically derived components of predator odour (2,4,5-trimethyl-3-thiazoline, TMT, a component of fox faeces scent; and 2-propylthietane, 2-PT, a component of mustelid scent) and to the natural scent of the least weasel (Mustela nivalis). It is well documented that rodents and several other small mammals show strong and at least partly innate fear reactions when confronted with these odorants. By contrast, the bats did not show any avoidance or fear reaction, despite the fact that relatively high odorant concentrations were presented. Furthermore, they did not react differently towards predator scent and towards acrid but otherwise neutral odours (basil or goat). The number of entries into in the Y-maze arm with the odour source and the time spent in this arm as well as the bats' overall exploratory activity and several other behavioural variables were not affected by the odour treatments. Generally, the sense of smell is well developed in bats and plays an important role in bat behavioural ecology. It is thus somewhat surprising that the bats did not show any avoidance reaction to predator scent, even though direct contact with a mustelid or fox would result in death. We discuss ecological explanations that might have prevented bats from evolving olfactory predatory recognition and avoidance.
Driessens
Tess
T
Max-Planck Institute for Ornithology, Sensory Ecology Group, 82319 Seewiesen, Germany.
Siemers
Björn M
BM
D000818:Animals; D001362:Avoidance Learning / Q000502:physiology; D001522:Behavior, Animal / Q000502:physiology*; D002685:Chiroptera; D004777:Environment; D005239:Fear; D005260:Female; D018782:Maze Learning; D009812:Odorants; D011235:Predatory Behavior / Q000502:physiology*; D013844:Thiazoles / Q000737:chemistry / Q000378:metabolism
C451263:2,4,5 trimethylthiazoline; D013844:Thiazoles