3 Fertility Facts About Feral Pigs

By Aaron Sumrall, PhD.

If there’s a problem with feral pigs, it’s that they keep making more feral pigs. And when it comes to wild pigs and reproduction, there’s a lot of misinformation out there. It’s time to set the record straight. Here's the three most pervasive myths and fertility facts about feral pigs.

Myth: Wild pigs start breeding at or before they reach six months of age.

Fact: Wild pigs have the potential to be physically and reproductively sound enough to breed at six months, but that’s not the norm. It’s more likely that a wild sow will wean her first litter before her first birthdate.

Myth: Wild sows have about three litters per year.

Fact: Swine gestation is 115 days (we tell our 4-H and FFA kids it’s three months, three weeks, and three days). So, three litters would take 345 days in gestation time alone – not even considering the time for the sow to regain the physical and reproductive health necessary for carrying another litter. Litter frequency is also tied directly to nutrition, and the lulls in available and sufficient nutrition can render wild pigs unfit to breed and/or rebreed. With adequate nutrition, it’s safe to predict that if a wild sow produces two litters in a year, the next year she’ll likely only produce one. Physiologically, her body can’t withhold much more and remain productive over time.

Myth: Litters can be as large as 10-12 pigs. 

Fact: The number of pigs in a litter can range from 1-12, depending on the sow’s age and body condition. Younger sows are physically smaller, so tend to have smaller litters with a higher fetal and/or piglet mortality rate. Body stress combined with no birth/mothering experience means higher mortality rates when compared to mature sows. With enough sustainable food resources, mature sows have the potential to produce larger, healthier litters. Bottom line: considering other variables, including disease and stress, the average litter size is 5, plus or minus 2 pigs. 

Regardless of the litter size and how many pigs are popping, the Pig Brig Trap System is effective for catching entire sounders, including sows and their piglets. 

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About the Author: Aaron Sumrall holds a Ph.D. in Wildlife Ecology from Texas A&M University. He runs a consultancy called Four Seasons Land and Wildlife LLC and has 20+ years of experience in wildlife and animal science management.

Photo: Layo Animals on Unsplash

References:

Mellish, J., Sumrall, A., Campbell, T., Collier, B., Neill, B., Higginbotham, B., and Lopez, R. 2014. Simulating Potential Population Growth of Wild Pig, Sus scrofa, in Texas. Southern Naturalist 13(2): 367-376.

Snow, N., Miller, R., Beasley, J., and Pepin, K. 2020. Wild Pig Population Dynamics. Book- Invasive Wild Pigs in North America, 1^st Edition.

Taylor, R.B., E.C. Hellgren, T.M. Gabor, and L.M. Ilse. 1998. Reproduction of Feral Pigs in southern Texas. Journal of Mammalogy 79:1325–1331.

West, B.C., A.L. Cooper, and J.B. Armstrong. 2009. Managing Wild Pigs: A technical guide. Human Wildlife Interactions Monograph 1:1–55.