Determining Body Mass of Wild Pigs from Body Measurements

Abstract

Animal body mass can be used to estimate age, determine health status, or guide dosage when administering sedatives. Because it can be difficult to weigh live large animals, using morphometric measurements to estimate body mass is sometimes used in field studies. Several statistical models exist for estimating domestic pig mass from morphometric measurements, but models based on domestic animals are likely unreliable estimators of wild pig (Sus scrofa) body mass due to known hybridization between domestic and wild pigs, and variable environmental conditions. The goal of this project was to evaluate several easily obtainable morphometric measurements as predictors of wild pig body mass and compare our estimates with those of models developed from both wild and domestic pigs. We measured neck girth, heart girth, body length, and body mass from 127 wild pigs in Florida and Georgia, and 450 wild pigs in South Carolina. Our best-supported linear model included body length as the best predictor of wild pig body mass. Our body length and heart girth univariate models produced similar estimates to those of other published models using these attributes, providing evidence that these models may be broadly generalizable. We also compared estimates from our model to estimates from models derived from domestic pigs and found significant differences between our model and two of the models developed from domestic pigs. Thus, while body mass may be reliably estimated from simple morphometric measurements from wild pigs, our results suggest morphometric models produced for domestic pigs are not reliable predictors of wild pig body mass.