Defensive responses of Wistar and Sprague-Dawley rats to cat odour and TMT.

Cat odour and trimethylthiazoline (TMT) are two predator odours commonly used to study defensive behaviour in rats. However their reported efficacy varies markedly across laboratories. We assessed whether rat strain differences might explain such variation. Wistar and Sprague-Dawley rats were tested for unconditioned and conditioned responses to both odours. Cat odour produced robust unconditioned and conditioned defensive behaviour, with notably stronger effects in Wistar rats. TMT produced limited unconditioned avoidance, but failed to elicit conditioned responses in either strain. Results support suggestions that faeces-derived odours such as TMT are less predictive of a predator threat than those derived from fur or skin, and identify the possibility that strain differences affect the defensive response seen to predator odours.