A multivariate analysis of phenotype and paternity in male harbor seals, Phoca vitulina, at Sable Island, Nova Scotia

Understanding the links between phenotype and reproductive successiscritical to the study of the evolution of mating systemsand life-historypatterns. We examined the relationship betweenphenotype and mating success ofmale harbor seals (Phoca vitulinaconcolour) at Sable Island, Canada.Cluster analyses of eighttraits including mating success determined bygenetic paternityanalysis, haul-out behavior, body mass, and mass changeidentifiedfour groups of males with distinct characteristics. The mostsuccessfulmales were of moderate body size, were rarely sighted alone,wereassociated with many different groups on shore, and weresighted on thehaul-out relatively infrequently. Large malesthat hauled out frequentlyalone, previously thought to be sociallydominant, were less likely to besuccessful. Also less successfulwere smaller, younger males. Contrary to ourhypotheses, andunlike most terrestrially breeding pinnipeds, body size andreproductiveeffort were not positively associated with mating success, andsomesuccessful males appeared to spend considerable time foragingin deepwater.