Overview
- A Biology Letters study detected the ethanol metabolite ethyl glucuronide in most samples from Ngogo chimpanzees, providing direct physiological evidence of alcohol ingestion.
- Of 20 urine samples, 17 were positive at a 300 ng/ml threshold, and 10 of 11 tested exceeded 500 ng/ml, levels used in some human screening but not proof of intoxication.
- Based on prior fruit measurements and feeding rates, the team estimates roughly 14 grams of ethanol per day, about one to two standard drinks adjusted for humans.
- Researchers collected urine non‑invasively during an August 2025 fruit glut at Kibale National Park using improvised plastic‑bag collectors, leaves, and puddles beneath feeding chimps.
- Findings strengthen the drunken monkey hypothesis, though selective preference for higher‑ethanol fruit and behavioral impacts remain unproven, with negative tests skewing toward females and juveniles.