DELAYED IMPLANTATION IN THE MARBLED POLECAT, VORMELA-PEREGUSNA-SYRIACA (CARNIVORA, MUSTELIDAE) - EVIDENCE FROM MATING, PARTURITION, AND POSTNATAL-GROWTH

In many species of carnivores, pregnancy is longer than expected based on maternal body size, as a result of delay in implantation. In this study on the marbled polecat (Vormela peregusna syriaca), pregnancy le ngth, and associated environmental factors were investigated from 1985 to 1989, in Israel. Data on mating dates, parturition dates, and post -natal development from captive and wild polecats revealed the existen ce of a long and variable pregnancy length (243-327 days) characterist ic of delayed implantation. Post-natal development of the captive born cubs resembled that described for other small mustelids. Results from a multiple linear regression model suggested that parturition date wa s related to average minimum temperature during the period preceding i mplantation (r(2) = 0.37). This result suggests that delayed implantat ion offers the female the ability to track environmental conditions an d allows greater flexibility in the timing of parturition.