Late-gestation ultrasonography without chemical restraint in a captive white-bellied spider monkey (Ateles belzebuth)

Summary Late-gestation ultrasonography was performed without anesthesia in captive Ateles belzebuth. Positive reinforcement enabled rapid, low-stress fetal assessment (<3 min). Fetal viability and biometric parameters (heart, chest, abdomen and head) were documented. Noninvasive ultrasonography supports conservation breeding of endangered primates.