Prediction of water, fat, and protein content of fisher carcasses

Recent findings suggest that measuring body protein and fat is necessary to evaluate the physical condition of carnivores inhabiting temperate and col d regions. We studied the body composition of fishers (Martes pennanti) to determine reliable predictors of body water, fat, and protein. We took morp hological measurements on 36 female and 34 male carcasses before grinding, homogenizing, and chemically analyzing them. We computed simple and multipl e regression equations relating body measurements and absolute mass of wate r, fat, and protein. Mesenteric-kidney-fat mass in males, and kidney-fat ma ss in females best predicted total body fat. Ingesta-free body mass and kid ney-fat mass best predicted protein content in females; neck circumference, mesenteric-fat mass and ingesta-free body mass best predicted protein cont ent in males. Body mass and a measure of abdominal fat served to estimate b ody water of males and females. All 6 regression models predicting absolute mass of body components covered a wide range of conditions (2-32% body fat ) and exhibited good fits, adjusted R-2 varying between 0.81 and 0.96. We a lso computed 2 regressions predicting percentage fat content, with R-2 of 0 .77 and 0.75 for males and females, respectively.