Evaluation and Ultrasonographic Validation of the Body Condition Score in Giant Anteaters (Myrmecophaga tridactyla Linnaeus, 1758)

Abstract

The giant anteater (Myrmecophaga tridactyla) is a unique species in risk of extinction nationally and internationally due to ongoing environmental and anthropogenic pressures, therefore requiring continuous conservation efforts. Under human care, obesity and nutrition-related diseases are major concerns. Body condition scoring (BCS) is an important tool for assessing animal fitness in natural and ex situ environments. This study aims to evaluate the applicability and reliability of BCS and morphometric measures, associated with ultrasound measurements of subcutaneous fat thickness (SFT), as tools to estimate the body condition of giant anteaters. Twenty free-ranging and twenty-two zoo-kept giant anteaters were assessed. The animals were weighed and classified by BCS, followed by biometric measurements and calculations of two body condition indices-the ratio index (RI) and the condition index 2 (ICC2). Subcutaneous fat measurements were taken by ultrasound in the lumbar, hip and flank of the captive anteaters. Captive animals exhibited higher body mass, BCS, measures of forearm, thorax, abdomen, neck, femur, tibia, humerus, RI and ICC2 compared to their free-ranging counterparts. Body mass correlated positively with all parameters except SFT. BCS showed moderate to strong correlations with body mass, RI, ICC2, thoracic, and abdominal circumferences. SFT correlated with BCS. Free-ranging anteaters consistently showed moderate BCS, while captive ones ranged from lean to obese, with relevant subcutaneous fat accumulation in the flank and hip. The resulting BCS protocol for the species was considered adequate to evaluate nutritional status under both free-range and managed-care conditions.