AGE-DETERMINATION OF THE RACCOON DOG IN FINLAND

We compared the age determination using the relative width of the pulp cavity in the lower canines and the one using the ossification stage of the epiphyseal cartilage of the radius and ulna with the most reliable method, namely, that based on the incremental lines in the tooth cementum in order to find a quick and reliable method for identifying young raccoon dogs Nyctereutes procyonoides (Gray, 1834), in Finland. Most juveniles could be identified by means of the pulp cavity/tooth diameter ratio in early autumn, and a remarkable proportion of them could still be separated from adults in late autumn and early winter. When using a separation point of 50%, only 2% of adults were determined as young. In spring, by contrast, the method is of no use, because the pulp cavity/tooth diameter ratio rearly exceeds 50% even in the young. All individuals killed before December were correctly aged from the ossification stage of the long bones. In December-January the proportion of incorrect determinations was 2-3%, but in spring it rose rapidly, being 17% in April-May. Until the end of February this method is very safe; no adults are determined as young. In conclusion, the best method for identifying juveniles in the present study is that using the ossification stage of the long bones until the end of February. The method using the relative width of the pulp cavity is less practicable especially in late autumn. Neither of these methods works well in spring, so, at that time all animals should be aged from the incremental lines.