Generalization of fear in farm mink, Mustela vison, genetically selected for behaviour towards humans

Mink offspring from two genetic lines, selected over 10 generations for confident (C) or fearful (F) reaction towards humans, were exposed to six different tests. The aim was to investigate whether this behavioural selection in mink has affected their reaction in other potentially fear-eliciting situations. A total of 192 naive mink, males and females, were tested over 6 weeks. C-mink had a shorter latency to get near and establish exploratory contact with a human than F-mink. F-mink maintained 6-10 times the distance to a human than C-mink. Similarly, C-mink had a markedly shorter latency than F-mink to approach and make contact with a novel object. C-mink also manipulated the object sooner and more often. In encounters with unfamiliar mink, C-mink were quicker to approach and establish nonaggressive contact than F-mink. C-mink had a shorter latency than F-mink to enter tubes within an X maze, and were more likely to visit these tubes. In contrast, F-mink made the most visits to other parts of the maze; number of visits may not, however, reflect just exploration. When presented with novel food, F-mink changed their behaviour more often than C-mink, indicating a higher degree of behavioural conflict. C-mink were also less hesitant than F-mink to approach and eat the novel food. In conclusion, offspring from a confident breeding line reacted with more exploratory behaviour than offspring from a fearful breeding line. Mink lines selected for behaviour towards humans thus generalized their fear responses across several social and nonsocial situations. (C) 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.