LONG-TERM HEARTRATE RESPONSES TO SOCIAL STRESS IN WILD EUROPEAN RABBITS - PREDOMINANT EFFECT OF RANK POSITION

The long-term mean heartrates of wild European rabbits living in a seminatural environment have been studied based on more than 1500 days of radiotelemetrical heartrate recordings. Significant differences between the heartrate levels of dominant and subordinate individuals have been found. Subordinate rabbits show chronically elevated heartrate that cannot be explained by limited access to burrow shelter or by the cumulative effect of heartrate reactions during aggressive encounters. If a subordinate rabbit achieves a dominant position, its heartrate is gradually adjusted to the lower level characteristic of dominant individuals. These results are discussed with respect to the consequences of dominance in species with different social systems.