Age Structure, Mortality, and Sex Ratio of the Raccoon Dog in Finland

We studied the age, sex structure, and mortality of a population of the raccoon dog (Nyctereutes procyonoides) in southern Finland from 1986 to 1990. The sex ratio was 1:1. There were no sexual differences in age structure. In the course of the study, the population declined slightly, which was taken into account when life tables were calculated. The age structure of the captures in autumn were rather stable in successive years. Life tables were calculated by two methods; by treating the captures from the breeding season (March–April) as a random sample of the population, and by treating the year-round captures (from August to May) as a sample of the animals that die in the course of 1 year. The two life tables did not differ statistically; the annual mortality rate of the population in southern Finland was 80.5% (54 and 51% for adults, and 88 and 89% for juveniles, respectively). According to the life table based on the random sample of the population, the mortality rate was lowest among 2–4-year-old raccoon dogs and increased after 5 years of age; maximum life span was 7–8 years. Because of heavy pressure from hunting, mortality among juveniles was high, which may have resulted in a high rate of reproduction.