Multiplying pigs

Pigs are the most prolific large mammal in North America. In some ways, they're like a big, ugly rabbit, capable of having two litters a year. Research indicates that we need to remove about helf of the wild hogs every year to keep the population levels under control. If not, their numbers grow in a hurry. 

Kim DeLozier & Carolyn Jourdan, Bear in the Back Seat II: Adventures of a Wildlife Ranger in the Great Smoky Mountains National Park (2014)