SURVIVAL OF WILD BOARS IN A VARIABLE ENVIRONMENT: UNEXPECTED LIFE-HISTORY VARIATION IN AN UNUSUAL UNGULATE

The wild boar (Sus scrofa) is a large, sexually dimorphic ungulate that exhibits a life-history tactic different from what would be predicted for a mammal of its size. In particular, litter size is larger and adult survival usually lower in wild boars than in other species of comparable size. We used capture-mark-recapture methods to model survival in a Mediterranean population (S. s. majori) of wild boars during an 8-year period, using a large sample of individually tagged animals of known age, to investigate demographic patterns and the effects of variable environmental conditions (e.g., summer droughts), which are believed to have a strong impact on the demography of this species. Contrary to the predictions based on our current knowledge of life-history theory, survival of wild boars differed less among age classes and between sexes than has been reported in other large mammals. As predicted from current theories on sexual selection, the impact of environmental factors was stronger on males than on females. This study documents for wild boars a life-history tactic different from the accepted model for large ungulates but similar to the tactic observed in small terrestrial mammals.