Breed differences in behavioural response to challenging situations in kittens.

In a previous experiment, the behaviour of Oriental/Siamese/Abyssinian (OSA) kittens was compared with that of Norwegian Forest kittens (NFO) in a repeated Open Field Test (OFT), and significant differences emerged. To further investigate such variations, we analyzed kittens' responses to a potentially threatening object (TO) during the OFT. It was a metal spring enveloped in a cotton case suddenly bouncing out of the cylinder after the first 6 min of OFT exposure, and the test lasted 6 more minutes. From the 4th to the 10th week of age, during each test, the response of 43 OSA kittens and 39 NFO kittens to the TO was analyzed. Heart rate (HR) before and after the test was recorded. Behaviours were recorded and analyzed by focal animal sampling. Behavioural modifications recorded after TO exposure confirmed our suggestions on slow limbic system development in NFO kittens, as previously suggested by poor habituation and poor memory retention of repeated OFT exposure. The evident avoiding response to the TO confirmed the adoption in NFO kittens of an active-coping strategy towards challenge, as indicated also by their high scores for exploration and escape attempts. Otherwise, poor TO influence on exploration observed in OSA kittens suggested the adoption of a passive coping strategy, as previously shown by low levels of exploration and intra-session reduction in the number of vocalizations. Nevertheless, some of the behaviours observed, and the evidence of emotional tachycardia in OSA kittens, suggested also that the low level of activity recorded could have been due to a low arousability predisposition in this breed. The perception of a poorly arousing potential in the experimental setting might have influenced the perception of danger and the behaviour adopted in OSA kittens. (C) 2010 Elsevier Inc. All rights reserved.