Accuracy of body weight prediction in Alpine ibex (Capra ibex, L. 1758) using morphometry

Area of Science:

• Wildlife biology
• Zoology
• Ecology

Background:

• Accurate estimation of body weight is crucial for wildlife population management and health assessments.
• Alpine ibex (Capra ibex) are a key species in Alpine ecosystems, requiring reliable monitoring methods.

Purpose of the Study:

• To analyze the relationship between body weight and various body measurements in Alpine ibex.
• To identify the most accurate predictors of body weight for this species.
• To evaluate the precision of linear measurements for estimating ibex body weight.

Main Methods:

• Linear and multiple regression analyses were applied to data from 227 Alpine ibex (162 males, 65 females) captured over 8 years.
• Predictor variables included age, sex, season, chest girth, and total body length.
• Stepwise multiple regression was used to determine the best predictive models.

Main Results:

• The relationship between weight and body measurements varied significantly by sex and season.
• For males, squared chest girth and age provided the best annual weight estimation.
• For females, age, total body length, and withers height were the best predictors.
• Despite using age and linear measurements, prediction intervals for body weight remained large, indicating low precision.

Conclusions:

• Linear body measurements are not precise or accurate predictors of body weight in Alpine ibex.
• Age is a consistently important predictor variable across models.
• Further research may be needed to develop more reliable methods for estimating ibex body weight in the wild.