Ecology and life history of the porcupine (Erethizon dorsatum dorsatum) in Nova Scotia

A. study of the biology of the porcupine in eastern Nova Scotia was conducted from April, 1969 to February, 1971. Weight and size of porcupines increased with age up to at least 43 months. Males were consistently heavier and larger than females in each age class. On a seasonal basis, the weights of adult porcupines varied from a mean of 8.1 kg in the fall (September to November) to a: mean of 7 kg in the late winter and spring (March to May). Porcupines were aged up to 43 months on the basis of tooth eruption and replacement. Annuli counts of the first molar were good indicators of age; however, dis= continuous annuli made it impossible to accurately age specimens older than 43 months. The litter size was one young per females Both sexes were sexually mature in their second fall (16 months), however complete physical maturity was not attained until approximately 43 months of age. Summer movements of porcupines ranged up to two kilometers with an average of 228 meters. Winter movement from dens varied according to the proximity of winter foods and the number of dens an animal was using during a winter season; however, the winter feeding area was approximately 10 hectares. The range of interseasonal movements varied according to the interspersion of summer and winter foods. The data from collected and tagged porcupines showed a male:female ratio of 100:96 in a sample of 370 animals. There were marked variations in the observed seasonal sex ratios, especially in the months of May (100 males:38 females) and June (100 males:210 females). The winter population densities as determined from surveys of two study areas were one porcupine per 7.8 hectares, and one porcupine per 6.8 hectares.