Observations on Feral Hog Ecology in South and Southeast Brazil (Abstract)

Abstract

Author(s): Wallau, Marcelo Osorio; da Rosa, Clarissa Alves; dos Reis, Tiago Xavier; Molinos, Nilson; Wallau, Carlos Augusto; Filho, La Hire Mendina | Abstract: Feral hog population has been increasing significantly in the past few years in Brazil. Rio Grande do Sul state has the largest sheep herd in Brazil and predation reports had grown exponentially lately. In Santana do Livramento County, 20,000 lambs were reported predated by feral hogs in 2013, resulting on approximately US$700,000 direct losses. Rising domestic pigs free-ranging is still a common practice, which increases the opportunity for breeding and hybridizing with the feral population, resulting in better environmental adaptation and reproductive ability of the offspring. American literature suggests that females can produce 1.6 litters per year with an average of 5.7 piglets per litter. However, reports from feral hog controllers in Santana do Livramento, in the Campos grasslands with short riparian forest, suggest a higher reproduction rate, where pregnant females carry from 3 to 14 fetus, averaging 7.5 piglets per litter (n = 61). According to simulation from data collected in Southern Brazil, feral hog populations could be increasing at a rate of 36% higher than what thought before. Survival rates also seem to be high, with repots of up to 12 piglets per litter at weaning age. This could be attributed to favorable climatic conditions and resources abundance (i.e. water and feed). Data from camera-traps in Itamonte County, Minas Gerais State, identified females farrowing once per year with an average of 2.3±1.6 piglets (n = 55) in continuous fragments of Brazilian Atlantic Forest. The Araucaria angustifolia seeds and local small crops are known to be important resources for feral hog population. Those are preliminary data of investigation being done in Brazil, and several more questions need to be assessed. An estimation of economic losses and potential of population expansion need to be done in both south and southeast of Brazil, where the feral hog invasion are concentrated. Those are key information for warning competent attorneys to the problem and to start a broader and more effective control planning.