A 400lb gorilla lies unconscious during a health checkup by vets at The Buffalo Zoo in New York.
Koga, the western lowland, undergoes a 'health MOT' every other year, checking for heart disease as well as the condition of his teeth, eyes, joints and muscles.
Incredible images from the procedure show the 34-year-old silverback clutching a veterinary nurse's hand while hooked up to heart-monitoring equipment.