LATE WINTER SOCIAL ACTIVITY IN PINE MARTEN (MARTES MARTES) - FALSE HEAT OR DISPERSAL

In late winter (February-March) the social behaviour of the pine marte n (Martes martes) is intensified (increased scent marking frequency, i ntersexual tolerance and intrasexual aggression) and the levels of sex hormones are increased, i. e. the same characteristics as for the mat ing period in July-August (pine marten exhibits delayed implantation). However, in late winter no fertilizations are possible, since males h ave no spermatogenesis at this time. Here, we review data on this ''fa lse heat'', including some of our own observations. We suggest that la te winter is the start of a dispersal period for pine marten, and that the main function of the social activity is territorial defence. The period coincides with the implantation and the beginning of the active pregnancy. This change in the female's reproductive cycle may start t he behaviour of driving out her young from the territory, and by that, the whole dispersal mechanism.