A boar bristle brush is one in which the filament or bristle comes from the wild boar. Boar bristles usually come from India or China where the animals are raised for their hair.Because boar bristles are soft and flexible, pure boar bristle brushes are excellent for fine, thin or baby-soft hair.Reinforced boar bristles add shine to medium/thick hair types.oar bristles usually come from India or China where the animals are raised for their hair. Because boar bristles are soft and flexible, pure boar bristle brushes are excellent for fine, thin or baby-soft hair. Reinforced boar bristles add shine to medium/thick hair types.