Today some 7,000 to 8,000 boars live in Berlin year-round, compared to an estimated 3,000 full-time city swine in 1989. An additional 3,000 to 4,000 of the animals move in during spring to search for food and places to bear their young—up to 12 per litter, which has prompted some scientists to start experimenting with boar contraception. They hope a “pig pill,” delivered through pellets left in food troughs in the forest, will help curb the species’ exploding populations.