Though it is possible for gilts to breed quite young, they will not usually be bred until at least one year of age. Males reach sexual maturity in 15 to 24 months but will not mate until they have reached their full size at five years of age. A sow's estrous cycle is about 21 days, and she will show standing heat for two or three days. The dominant sow of the herd will cycle first, shortly followed by the rest of the group. A sow will average five piglets per litter over the span of her life, although she may have up to ten piglets at one time.
Females have excellent mothering instincts.
In preparation for parturition, sows will build a comfortable nest of grass, moss, leaves, and whatever is available. She will stay in this nest with her litter rarely leaving, and eating only a very small amount of solid food for one or two weeks. After this initial bonding, the piglets will leave the nest with their mother and they will be communaly nursed and cared for by the whole matriarchal group. While the males are usually only aggressive during the rut, the females are territorial and very protective of their young during farrowing and for some time afterward. Wild boar are potentially dangerous because of their size and their tusks, but they don't attack unless provoked.