Javelinas can breed any month of the year, but most births occur in May, June, or July, after a five-month gestation period. This may be to correspond with the summer rainy season. They first breed at about one year of age and continue to breed throughout their lifetime. Females give birth standing up and nurse the young for two months. The average litter size is two, but occasionally is as high as five. By six weeks of age the young are capable of eating solid food. By forty weeks, the young are full-grown. There is typically a 50% or higher mortality rate for the young. Coyotes, bobcats, black bears, and mountain lions prey on javelinas.
On average, javelinas live 7.5 years in the wild. Javelinas live in groups (or bands), but do not form long-term pair bonds. Band size ranges from five to twenty seven animals, with an average of fourteen per band in Big Bend National Park. From nps.gov